Artificial limb development: A history of the Northrop Artificial Limb Research Department 96, project 17, founded on prosthesis development

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ARTIFICIAL LIMB DEVELOPMENT A HISTORY OF THE NORTHROP ARTIFICIAL LIMB RESEARCH DEPARTMENT 96, PROJECT 17, FOUNDED ON PROSTHESIS DEVELOPMENT

A Thesis Presented to the Faculty of the Department of History The University of Southern California

In Partial Fulfillment of the Requirements for the Degree Master of Arts

by Gordon Warner Lieutenant Colonel, United States Marine Corps, Retired June 1950

UMI Number: EP59620

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T h is thesis, w ritte n by

GORDON WARNER 4g under the guidance of h

F a c u lty C o m m itte e ,

and a p p ro ved hy a l l its members} has been presented to and accepted by the C o u n c il on G ra d u a te S tu d y and Research in p a r t ia l f u l f i l l ­ ment o f the requirements f o r the degree of

MASTER OF ARTS ..... _ ...HISTORY

n„„

March 10, 1950

Faculty Committee

ACKNOWLEDGMENT I wish to express my sincere thanks and appreciation to the Medical Department of the United States Navy, for without its benevolent care I could never have lived to write this study. My humble thanks are extended to Mr. John K. Northrop for his vision beyond machines, to Mr. Mike Fishbein for requesting me to be the first suction socket test pilot, to Dr. Henry H. Kessler and Dr. Douglas D. Toffelmier formerly of the United States Navy Medical Department at the Amputation Center, Naval Hospital, Mare Island, to Dr. Leonard T. Peterson and Lieutenant Colonel M. J. Fletcher for their encouragement from the Medical Department of the United States Army, to Admiral J. P. Owen (MC), United States Navy for his assistance in our Rehabilitation at the United States Naval Hospital, Mare Island, California, to Colonel Robert S. Allen, United States Army, Retired, for his dogmatic stand in obtaining better prosthesis for disabled veterans. My gratitude to a gracious lady, The Honorable Edith Nourse Rogers, Massachusetts, for she has carried the problems of the seriously disabled veterans before the lawmakers. To Dr. Francis Bowman for his interest and guidance, I pay tribute.

To Dr. Irving Rehman the author is indebted

for a critical review of the anatomical and physiological content of this thesis.

To Mrs. Eleanor Pooley Mealy for

her able assistance in editing this work.

PREFACE This thesis is presented with a two-fold purpose: to enlighten the layman concerning the fitting of artificial limbs that are now based on well-established scientific theories and to point out the historic value of the search for better prosthetic devices. The construction of an artificial limb should be based on a thorough knowledge of the natural limb.

This

statement, which might appear self-evident, was overlooked until recent times.

Even now in many countries of the world

the manufacture of artificial limbs is still in the hands of persons who have little scientific knowledge and lack advanced training in educational institutions.

Since there

is no control of the manufacture or sale of artificial limbs in any country, anyone who chooses to do so may make and sell these prosthesis. Volumes have been written on the medical research and technical developments of the suction socket phase and on the very controversial questions concerning cineplastics. This study, however, deals with the historical data of a great humanitarian research problem.

Improvements of arti­

ficial limbs that will assist disabled men to develop their remaining capacities is the foremost problem of today. Solutions to the circumstances preventing disabled persons from becoming fully employed in a gainful and

substantial occupation is increasingly necessary*

Results

of this research will assist competent national and world organizations to make an attempt to carry on the permanent international spread of information concerning the best types of artificial limbs, especially those required for essential rehabilitation*

GORDON WARNER

TABLE OF CONTENTS CHAPTER I.

PAGE

THE PROBLEMS AND DEFINITIONS OF

THETERMS USED .

1

The p r o b l e m ...................................

1

Definitions of terms u s e d ...................

1

I I • HISTORICAL BACKGROUND

..........................

4

Ancient period ................................

4

..............................

5

................................

6

Medieval period Modern period

Present d a y ................................... Medical advancement

..........................

10

European prosthesis

..........................

17

American prosthesis

..........................

19

Constructional materials ..................... III.

9

21

THE DEVELOPMENT OF THE RESEARCH PROGRAM ON ARTIFICIAL LIMBS IN THE UNITED STATES OF A M E R I C A .......................................

IV.

24

THE NORTHROP AIRCRAFT, INCORPORATED,ARTIFICIAL LIMB RESEARCH DEPARTMENT 96, PROJECT 17

. . .

Artificial a r m s ..............................

37 44

Artificial hands project developed by the Sierra Engineering Company under Northrop Aircraft Incorporated

......................

Basic design requirements - h a n d ...........

49 54

vii CHAPTER

PAGE A r m ..............................................58 Muscles available for use as motors

• .

•

•

60

Hand d e s i g n ................................

61

Hand design

3 A .............................

65

Hand design

3 B .............................

64

Hand design

4 A .............................

64

Force m u l t i p l i e r s ..........................

67

C h a i n ......................................

69

Sense of touch m e c h a n i s m ...................

71

Cosmetic g l o v e s ............................

72

The arm by Sierra Engineering Company

73

•

• •

T e s t i n g ....................................

76

C o n c l u s i o n s ................................

78

Artificial hands project developed by Vard, Incorporated ................................

79

Otto B e r g b a u e r ..............................

89

Leo Qualiotto and Walter S u l l i v a n .........

91

Development of the a r m ........................

96

Below-elbow arm with wrist rotation

• •

•

•

Development of the w r i s t ................. *

96 97

Results of new development

106

Below-elbow, wrist-rotation arm with cineplastic control of h a n d s ............ ..

•

107

Results of the p r o g r a m ......................

110

viii CHAPTER

pAGE Above-elbow arm with e l b o w - l o c k ...........

Ill

Development of above-elbow a r m .......... •

112

Results of the s t u d y ........................

119

Above-elbow arm with coupled forearm lift rotation, and wrist flexion.................

120

Development of r e s e a r c h ...................

122

Above-elbow, 3-rod type arm with wrist flexion and forearm rotation

V.

*

123

Results of s t u d y ............................

126

ARM AND HAND C O N C L U S I O N S ........................

127

Conclusion of artificial hand and arm study D e s c r i p t i o n ................................

127 128

Mechanical hand No. 3 with leaf-spring f i n g e r s .................................. Prehensible palm hand, model No. 4 .......... Review of hooks studied on the project VI.

ARTIFICIAL L E G S ................................ Northrop experimentation on artificial Suction sockets

legs •

137 140 148 153

............................

153

Comparison of socket types ...................

156

...................

162

Making the suction socket Suction socket valves

VII.

• •• •

133

........................

168

Summary of r e s u l t s ............................

175

PLASTICS, PLASTER, AND COSMETIC COVERING . . . .

177

ix CHAPTER

VIII.

PAGE Cosmetic c o v e r i n g s ..............................

178

Summary of r e s u l t s ..............................

181

LIMB FITTING T E C H N I Q U E .......................... Upper extremity

.........................

Lower e x t r e m i t y ............................ Procedure for types I

andII sockets • • • • •

183 183 185 186

M e a s u r e m e n t ............ .. ...............•

186

Plaster w r a p ................................

186

Male r e p l i c a ..................................

188

Male m a s t e r ................................

191

Preliminary socket ..........................

195

Fitting preliminary socket ....................

198

Final alignment

201

.........................

Final fitting and a d j u s t m e n t ...............

202

Procedure for type IIIs o c k e t ................

205

Fitting and alignment fixture

206

Discussion of results

................

.......................

216

C O N C L U S I O N .......................................

217

B I B L I O G R A P H Y .................... .......................

226

APPENDIX A .............................................

233

IX.

APPENDIX B ...............................................

236

APPENDIX C ...............................................

238

APPENDIX D ...............................................

244

APPENDIX E ...............................................

246

LIST OP FIGURES FIGURE

PAGE

1.

Gordon Warner, Left AK, Northrop Limb Tester • Frontispiece

2.

Below Elbow A r m .............................. • •

40

3.

Below Elbow Amputation Prosthesis

47

4*

Lonnie Carberry, Double Arm AE, Northrop Limb

. . . . . . . .

T e s t e r ...................................

50

5.

Bowling, Charles McGonegal, Bi-lateral, BE, Arm

•

6.

Above Elbow Amputation Prosthesis

7.

Above Elbow Arm, Automatic Rotation and Flexion

8.

Mechanical Hand, Model 2 .........................

65

9.

Utilization of Standard Hook for Manual Operations

74

10.

Wrist Disarticulation

...........................

81

11.

Lonnie Carberry Utilization of Standard Hook . . .

83

• • • • • • • • •

Hand...............

53 55 57

12.

Below Elbow, Cineplastic, Right

13.

Otto Bergbauer, BE,

Cineplastic Arm, Front View

•

88

14.

Otto Bergbauer, BE,

Cineplastic Arm, Back View . .

90

15.

Otto Bergbauer, BE,

Cineplastic Arm, Side View . .

93

16.

Cineplastic, Wrist Disarticulation ...............

95

17.

Below Elbow Prosthesis ...........................

99

18.

Above Elbow Prosthesis ...........................

101

19.

Prosthesis Elbow U n i t ..................... 104

20.

Jerry Leavy, Double Arm Amputee, AE and BE . . .

21.

Elbow Locking S y s t e m ........................ .....

22.

Hook with Chain C o n t r o l ...................121

.

85

113 117

xi FIGURE

PAGE

23.

Rod Type Prosthesis

. . . • • • ...........

24.

Experimental Mechanical Finger .........

25*

Mechanical Hand, Model 5 . . . * . . . . . * » *

132

26.

Experimental Hydraulic Finger

134

27.

Link Type, Center Pull Hook, Open

• • • • • • •

139

28.

Above Elbow Prosthesis

.............

143

29.

A K Leg with Mechanical Knee.First Northrop Conventional Type Leg

124

• • • •

• • • • » • • • •

• • • • * • • • • • • •

30.

Temporary Plastic Socket . . .

31.

Exploded View - Meohanical Type Leg

32.

Above Knee Suction Socket Pylon

129

152

• • • • • • • • .

154

• • • • . •

157

. . . • * • • •

161

33.

Flapper Type Valve • • • • • • • • . . . • • • «

171

34.

Flapper Valve Seated in Plastic Socket • • • • •

173

35.

Prosthesis Leg Fitting and Alignment Fixture • •

184

36.

Thigh Stump, Male Replica from Plaster • • • • •

189

37.

Measuring Air Pressure • • • • • •

192

38.

Pylon Fitted to Amputee

• • • • • • • • • • • •

197

39.

Inserting Stump into Pylon . • • • • • • • « • •

199

40.

Knee Lock

203

41.

Fitting Fixture Hip Alignment

42.

Fitting Fixture Hip Axiri.................

43.

Fitting Fixture Knee Axis

44.

Checking Stump Deformation • • • • •

45.

Stump to Floor A l i g n m e n t ........................

•

• • • • • • • • • • • • • • • • • • » • • • • • • • • •

207

. . .

• . . . • • • • • • • .........

208 209

•

210 212

xii PAGE

FIGURE 46*

Measuring Ischeal Tubersity Height

. . * * * • •

814

47.

Anatomical Knee Construction AK Leg

• * * • • •

218

48*

Bi-lateral Arm Amputees Bowling

• « * • • * • •

225

49.

Anatomical, Knee, AK

...........

Appendix*

CHAPTER I THE PROBLEMS AND DEFINITIONS OF THE TERMS USED I.

THE PROBLEM

In the development of the artificial limb research 'program, two problems confronted the engineers#

They had to

design a scientific prosthesis which would be anatomically and physiologically as perfect as possible; and they had to construct this artificial limb to function as normally as the human limb.

An effort was also made to shorten the

rehabilitation time for the amputee who had to learn to use an artificial device*

To achieve these two aims the engineers

had to create a limb that would be comfortable and hygienic. The functional value of a stump is determined by its efficiency when fitted with a prosthesis#

Its effective

functional value is therefore dependent on various factors which are themselves determined by the condition of the stump, the nature of the orthopedic appliance, and the physical and mental condition of the patient.

Time has

proven that the condition of the stump and the psychological factor are important in rehabilitating the amputee# Some amputees provided with quite ordinary prosthesis succeed in obtaining surprising results, while others with highly perfected modern appliances often are unable to derive

2 any benefit or use.

Orthopedic specialists the world over

have observed these facts and they focus the necessity of training the amputee in the use of his appliance as well as conditioning him to the problem of utilizing his limb to the 1 utmost. The nature of the orthopedic appliance obviously affects the efficiency of the amputee who wears it, and the importance of this factor can not be exaggerated* Beside the attainment of the proper power of standing and locomotion, the development of simplified parts and dependable mechanical functions has now presented a new research problem. II.

DEFINITIONS OF TERMS USED

The Identification of the word 11pros the sis” should be the first term discussed in this paper on the development of artificial limbs* The word ffprostheses” originally was a Greek word that meant "an additional;

something added or put to.”

From the

Greek word, the English noun prosthesis was derived and has two meanings:

(1) the replacement of an absent part of the

body by an artificial part, as a leg, an arm, an eye, a set of teeth, hair, and such; and (2) the artificial part itself.

1 Atha Thomas and Chester C. Hadden, Amputation Prosthesis (Philadelphia: J. B. Lippincott Company, 1945), p. vii.

The adjective is prosthetic, such as a prosthetic appliance or invention*

From this adjective is derived an

additional noun, "prosthetics,” meaning "that branch of surgery or dentistry which specializes in artificial parts or organs•" The word prosthesis was not listed in all of the editions of the standard dictionaries in the libraries at the University of Southern California and University of California at Los Angeles, Columbia University or the Library of Congress.

CHAPTER II HISTORICAL BACKGROUND I.

ANCIENT PERIOD

This story, leading from the first crude prosthesis used to replace the amputated member lost as a result of battle wounds from sword, ax, or arrow, is one of great suffering.

The torture chambers and conflicts with wild

animals also resulted in amputations. In 438 B.C., Herodotus records that Hegestistratus, after being taken prisoner was chained up to die, but escaped by freeing himself through amputating his chained foot.

When

the wound healed, he provided himself with an artificial limb. It is believed that the amputation was just over the ankle.^ Aristophanes (circa 400 B.C.) writes of a leg support 2 worn by an actor in one of his plays. It is recorded that the Roman, General Marcus Sergius, lost his right hand during the Second Punic War (218-201 B.C.) after which he had an iron hand constructed which he used with great destructive dexterity in combat.

3

1 Atha Thomas and Chester C. Hadden, Amputation Pros­ thesis (Philadelphia: J. B. Lippincott Company, 1945), "p~. T7 2 Ibid., p. 2. ^ A. A. Marks, Manual of Artificial Limbs (New York: Marks Company, 1920), p. 3.

5 Along an old Roman highway an antique artificial limb was unearthed during a recent archaeological excavation.

The

craftsmanship indicated that the theory of the basic knee joint was that of the pendulum--the shin and foot swinging forward from the axis of the knee joint*

This idea of the

basic knee joint has been standard throughout the entire commercial limb industry* II.

MEDIEVAL PERIOD

Probably the most historical of all medieval prosthesis is the artificial hand worn by Goetz von Berlichingen (1480 1562) who lost his right hand in the Siege of Landshut in Bavaria (1504) and who had a most ingenious artificial hand 4 constructed by metal craftsmen. Von Berlichengen was surnamed ,fGotz with the Iron Hand; " models of the metal hand worn by von Berlichingen are still in existence in Europe and present an amazing example of the skilled craftsmanship of that period.

5

Many of the artificial hands made during the early period show an amazing likeness to some of the more popular models in use today*

Although many of the early appliances

were never used, the artisan who constructed the artificial 4 Webster♦s Biographical Dictionary (first edition; Springfield: The G. and C. Merriam Company, 1943), p. 141. 5 Henry H* Kessler, Cineplasty (Springfield: Charles C. Thomas and Company, 1945), p. 28*

devices had a very definite objective, either functional or aesthetic*

Some of the hands were fashioned to enable the

wearer to exert pressure and grasp objects; others were ornaments designed only to cover up the artificial hand or leg*

Since the artificial limb makers of the early centuries

were makers of armor, cuirasses, and swords, they designed the artificial limbs to conceal the soldier's loss, their products reflected the influence of the art of armor making which had reached a great degree of perfection, particularly in Italy and Germany* Ambroise Pare (1509-1590) was probably the first to recognize prosthesis as natural supplements to surgical amputations*

Many of his designs for artificial legs and

arms contained some of the essential principles of present day prosthesis.

6

III.

MODERN PERIOD

During the eighteenth and nineteenth centuries the surgeons were making great progress in improving the surgical techniques of amputations to give a better stump, the limb makers also were improving methods and developing prosthesis to fit the stump thus created by the skilled surgeons•

® Thomas and Hadden, o£. £ i t ., p. 5*

In England, the "Anglesey leg,” was so named because it was first created for Sir Henry William Paget (1768-1854) the Marquis of Anglesey, who lost his leg in the battle of Waterloo 1815.

The Anglesey leg was created for him by an

English craftsman by the name of Potts.

The kneepiece and

top of the shin, also the lower end of the shin and foot were manipulated by means of tenon and mortise joints.

The knee

was connected to the foot by catgut tendons in such a manner that flexion of the knee caused dorsiflection of the foot, while extension at the knee produced extension at the ankle. This type of prosthesis is still used to some extent in Great Britain. In the nineteenth century the "Palmer leg” (1846) was invented in Philadelphia and held claim to being an improve­ ment over the "Anglesey leg.”

The "Palmer leg” had a foot

made somewhat on the m o d e m American pattern, but with catgut cord and an anterior spring instead of the rubber bumpers in the foot.

This leg was awarded first prize at the W o r l d fs 7 Fair in London in 1851. The "Bly leg” invented and patented in 1868 by Douglas Bly, M.D. of Rochester, New York, was popularly known as "Doctor B l y rs Anatomical Leg.”

This leg, through the use of

a polished ivory ball, functioned in a socket of vulcanized

7 Ibid., p. 5.

8 rubber and controlled by cords and rubber washers, was intended to duplicate all the natural motions of the ankle. Doctor Bly is also said to have been the first to introduce the curved knee joint, which is now generally used on all below-knee limbs. The heavy casualties of the Civil War drew new attention in the United States to the development of arti­ ficial limbs. The firms of A. A. Marks8 (1853) and J. E. Q Hanger (1861) prominent during that period, are still well known throughout the world for their contributions to the development of modern prosthesis. The "Marks Leg" was the first to introduce the use of a rubber foot, and the "Hanger" was the first to perfect the cordless ankle and the wood socket.

Heretofore, the sockets

of artificial limbs were made of leather. A review of literature describing the prosthesis made during the later half of the nineteenth century indicated that many of the limbmakers themselves wore artificial limbs.

® A. A* Marks of New York presented drawings in his book on fitting the amputee with a prosthesis. These drawings are still utilized in most commercial limb fitting shops. The book contains an adequate collection of drawings and personal statements for a clear understanding of the problems of the amputee during the turn of the century in employment and social activities. ® See Appendix B.

9 IV.

PRESENT DAY

The beginning of the twentieth century saw many new names added to the list of those who were contributing to the development of artificial limbs:

the Rowley Brothers of

Chicago, Detroit, and Pittsburgh; Frees and Pomoroy of New York; Milligan of Los Angeles; Gaines Erb of Denver; Hittenburger of San Francisco; and Winkley and Buchstein of Minneapolis* At the time the United States entered World War I there were approximately two hundred established artificial limb manufacturers in the United States, employing around two thousand skilled workers*

10

Marcel Desoutter of England, who in 1912 had lost a leg above the knee in an airplane accident, recognized the need of a lighter material for the construction of above-knee prosthesis*

Marcel Desoutterfs brother, Charles, an aero­

nautical engineer, finally developed the first successful light-metal limb*

This limb was made of aluminum*

The

aluminum limb is very popular in England where it is used almost exclusively.

Desoutter and the Hanger Company devel­

oped forms of pelvic suspension which provided more positive and efficient control of the prosthesis and led the develop­ ment of modern knee-control mechanisms*

This idea led to the

10 See Appendix E for a list of established artificial limb manufacturers.

10 knee brake, which has contributed to improving efficiency and acts as a safety factor in walking with an above-knee prosthesis. Notable personages who had to make a return to produc­ tivity in society demanded that advancements in artificial aids be made*

11

They rebelled against the possibilities of

facing society in a mutilated condition, and set about demanding functional prosthesis to take the place of the amputated member* V.

MEDICAL ADVANCEMENT

Mr* Vanghetti of Italy Is given the credit for first conceiving the idea of cineplasty in 1898*

Mr. Vanghetti

was not a surgeon, but an inventor and experimentor.

His

first subjects were chickens.

By 1907, two amputees had 12 been operated upon with successful results. Many different types of cineplasty were suggested or tried, but they can be divided roughly into two groups:

the loop and the club.

loop included muscle and tendon tunnels, a skin covered tendon loop extending past the end of the stump, and a jug handle type of loop on the side of the arm stump which was created by isolating a part of a muscle in the forearm, elevating it and covering it with skin. 11 Marks, op. cit* * p. 184. 12 Kessler, o£. cit*s p. 52*

The

11 The club motors were constructed by isolating the distal end of a tendon leaving it attached to a piece of bone and covering the tendon with a skin graft.

13

All forms of cineplastic methods were finally abandoned in Italy after the leading surgeons there had tried them without success*

Cineplastic methods had been tried and

given up in Argentina, Great Britain, Sweden, and other countries* It remained for Doctor Sauerbruch, in Germany, to concentrate upon the muscle tunnel type of cineplastic motor during and after World War I*

14

Doctor Sauerbruch and some

of his followers are still using this method to some extent in Germany, although the Krukenberg operation has supplanted cineplasty to a large extent for amputations below the elbow, particularly for blind amputees.

15

The Krukenberg operation

consists of a division of the muscles and two bones of the forearm, making two flfingers,! of bone and muscle about six

13 Ibid., p* 54. 14 Lieutenant Colonel Rufus Alldredge, MC, Chief of Amputation Section, England General Hospital, Atlantic City, New Jersey 1946 states that the only cineplastic method still In use in Germany is that of Sauerbruch, developed in Germany during and after World War I. The cineplastic method was in active use chiefly in two European centers, Munich and Berlin. 13 Colonel Leonard T. Peterson, MC, Chief of Amputation and Prostheses Unit, Surgeon General*s Office, Report of European Observations§ by Commission on Amputations and Pros­ theses, 1946, p. 46.

12 or eight inches long.

After a short training period, the

amputee learns to use these "fingersft to grasp an object as he might between his thumb and forefinger.

The particular

advantage for a blind amputee is the fact that the sense of touch is retrained.

16

There are many surgeons in Germany who do not consider the cineplastic method worthwhile because they saw so many failures after World War I.

17

Doctor Lebsche, in Munich,

however, has obtained results which, purely from the surgi­ cal standpoint, go far toward refuting the unfavorable criticisms of the cineplastic procedures.

18

There are

amputees fitted with a cineplastic device who will wear no other type prosthesis.

19

At this writing, the cineplastic method of Doctor Sauerbruch and Doctor Lebsche has been carried on in the United States to a limited extent.

20

The results have not

been convincing to many of those interested in the functional rehabilitation of amputees, principally because of the 16 Ibid.. p. 47. 1? Ibid., p. 57. 18 Professor Max Lebsche, Erste Chirurgische Clinic, Purstenried Hospital, Munich, Germany. 19 Hearings before the Committee on Veteran1 Affairs House of Representatives, Eightieth Congress, April 15, 23, and 24, 1947. 20 See Figure 4, page

85, German cineplastic arm.

13 present lack of adequate cineplastic prosthesis.

21

Turning from the upper extremity to the lower, loss brought about a great many more problems than were foreseen. The suction socket method of securing an artificial leg to an above-knee stump, although the subject of United States patents in 1863, apparently was not used extensively until about 1930, when German limb makers began fitting suction socket limbs to patients.

22

Many successful cases were

observed in Germany by the Surgeon General*s Commission in 23 1946; in fact, the suction socket was found to be in almost universal use for above-knee amputations in the United States 21 Recently, the Committee on Artificial Limbs of the National Research Council has done much work on the cineplastic method. Physiology of muscle motors has been studied. Results indicate a definite need for compensatory mechanism in the prosthesis to take the place of the natural ones which were lost through amputation. When much better prosthesis are available, the method of cineplastic prosthesis will be extended. 2% The earliest known reference to the suction socket is in the form of a patent issued by the U. S. Patent Office, February 10, 1863 (Patent No. 37,637) to Dubois D. Parmelee of New York City, New York. The principal idea was the attach­ ment of the socket to the stump by atmospheric pressure. Sub­ sequent patents have been issued to George C. Beacock and Terence Sparham of Brockville, Ontario, Canada, in 1885; to Justin Kay Toles of Stockton, California, in 1911; and to Ernest Walter Underwood of Birmingham, England, in 1926. Fundamental principles of the Beacock and Sparham suction socket differ but little from the Parmelee socket; Toles * description was basically the same, but with the addition of a rubber tube and bag lining which could be inflated by air to assist in holding the socket on. The socket described by Underwood had smooth helical grooves which he claimed venti­ lated the stump as well as assisted in holding the socket in place. 23 Peterson, o£. cit., p. 79.

14 Zone of Occupation, which was the only zone visited.

24

The only apparent difference between a suction socket leg and conventional above-knee limb is the elimination of the pelvic hinge and all suspension harness.

The leg is held

on to the stump by a small amount of negative pressure, or suction, created in the carefully fitted socket by the action of the stump. an air seal.

The socket must fit snugly in order to maintain The sealing of air should not be so tight as to

restrict the muscles of the stump which now must be used to control all motions of the leg. No stump sock is worn on the 25 stump. If the socket is fitted properly, there is little piston action of the flesh moving up and down adjacent to the side wall of the socket. A thin stockinet is used by the amputee to pull the fleshy portions of the stump into the socket.

The stockinet

is carefully pulled off the stump and out of the socket through the small valve held.

After the stump has been seated in a

comfortable position with the leg alined, the valve is screwed into place while normal weight is on the artificial limb, 24 An effort was made to include Russia and the Russian German Zone during the Commission^ European Observations, but the Soviet Government did not consider the circumstances opportune and necessary permission to enter Russia was not granted. 25 a conventional limb stump stocking is made of 100 per cent virgin wool. This was found to be the best material that could be utilized for absorbing perspiration when the stump was fitted into a conventional socket.

15 thus preventing air from entering the socket, giving the socket a perfect seal,

26

A program of experimentation and research into this method was established by the Committee on Prosthetic Devices and while results thus far obtained in selected cases have been highly encouraging, the method of the suction socket is still considered to be in the experimental stage.

27

One result of the improvements made in the design of artificial limbs is the realization by the surgeons that the use of a prosthesis must be considered at the time of the amputation.

Closer establishment of cooperation between the

surgeon and the limb maker developed through the idea of the location of the amputation for a perfect artificial limb fit. This professional approach on the part of the surgeon and the cooperation of the limb maker provided the patient with the 28 knowledge that consideration was given his case. It has been determined in the past few years that the maximum stump length is not the primary consideration. Further, excessive stump length is often found to be quite disadvantageous.

A long stump causes circulatory disturbances

26 This action should be followed at least twice per day to prevent irritation to the skin. 27 Supplying the amputee with the best devices obtain­ able, fitted as expertly as possible, is essential for the maintenance of a progressive program. 28 Marks, o£. cit., p. 165*

16 and adds to the difficulties of fitting a prosthesis and shaping the socket.

Through a study of stump lengths it has

been found that the upper thigh amputation provides the most suitable location for fitting an artificial limb. The ideal stump is conical in shape, not bulbous, and there should be no redundant soft tissue at the end of the stump. A view still commonly held, but which has been proven entirely erroneous, is that the end of the amputated member should be protected by a thick cushion of muscle. not the rule even in an end-bearing stump.

29

This is

A bulky mass

of flabby tissue projecting beyond the end of the bone serves no useful purpose, makes the fitting of the socket far more difficult, and only adds to pressure and circulatory dis­ turbances by the wearer. Amputations are now based on the assumption that the primary amputation is performed as an act of deliberation and choice, not as an emergency procedure, -unless suppuration has begun and a secondary amputation is carried out by the surgeon.

Where there is no hazard of infection and conditions

are excellent, the site is carefully chosen with respect to the future use of a prosthesis, and the functional requirements

29 The weight of the amputee is carried on the end of the stump in a thigh-laced prosthesis. No pelvic belt or harness.

17 30 of the s tump• Through the ingenuity and skill of the experienced limb maker, a poorly formed stump can be satisfactorily fitted with a serviceable prosthesis. In addition to the requirements of the stump itself, efficient use of the prosthesis demands that there be normal mobility and stability of the joints proximal to the site of amputation and that there be good coordination of the muscles controlling the stump.

Unremitting attention to post

operative care and preparation of the stump for fitting of the prosthesis are of the greatest importance in attaining these desirable functional requirements. VI.

EUROPEAN PROSTHESIS

Prosthesis of leather are called European prosthesis because before 1914 they were most generally used in Europe; those made of wood were occasionally found in this continent.

31

The European prosthesis is made of molded leather supported by a metal framework.

Its socket, which is

strengthened by lateral plates, laces around the stump.

The

metal plates give support and carry the artificial joints. 30 Discussion with Captain Lawrence L. Bean, MC, U. S. Navy, Chief Surgeon, and Captain Ralph R. Meyers, MC, U. S. Navy, Chief of Orthopedics, U. S. Naval Hospital, Long Beach 4, California, 1949. ^ Florent Martin, Artificial Limbs (Geneva: Inter­ national Labor Office, 1924), p. 68.

18 European prosthesis are made to lace up the front so that the appliance can be adapted to changes in the stump*

32

The ankle and foot of the artificial limb are in general made of wood.

Sometimes the foot is made of wood

and the ankle of sheet metal*

Formerly there was much dis­

cussion of the relative advantages and disadvantages of metal and wooden ankle joints*

The metal ankle joint was

said to be too hard for the foot and cut it to such an extent as to limit its function considerably* European prosthesis is empirical in construction;

the

leather and metal parts which compose it are ill-adapted for scientific manufacture*

This type of prosthesis is gradually

disappearing and being replaced by more highly perfected American prosthesis*

33

Military hospitals apparently do not have amputation centers as in the United States but have ffOrthopedic Centers,11 of which there are about twelve in number throughout Great Britain.

34

France controls the amputee program from the

32 Ibid., p. 69. 33 Martin, loc* cit* 34 Standing Advisory Committee on Artificial Limbs: Sir Charles Darwin, The National Physical Laboratory A* W. J* Craft, Esq., Queen M a r y ’s Hospital A. L. Eyre-Brook, Esq., Litfield House, Bristol E* Ramsay Green, Esq*, Westminster, London Professor T. P. McMurray, Liverpool L. P. B. Merriam, Esq., Knightsbridge, London G. Perkins, Esq., Queen M a r y ’s Hospital Sir A* Rowland Smith, Ford Motor Company, Ltd., Essex K. S. Watt, Esq., Queen M a r y ’s Hospital

19 Rehabilitation Center for Amputees at the War Ministry. Sweden, Switzerland, and Germany have large programs for the advancement of prosthesis. VII.

AMERICAN PROSTHESIS

Wooden prosthesis are known as American, so called because their use has become general in Europe through the initiative of American limb makers.

This type of limb is

now very widely used in all the countries that took part in World War I, but were known in Europe, particularly in Germany 36 and Great Britain, before 1914. Appliances of the American 37 type were manufactured in Germany in 1908. The distinctive features of American prosthesis is the material used in its construction. used.

Mountain willow or lime wood are generally

These are well-seasoned woods.

The latter is theoreti­

cally the best, as it has the highest coefficient of resis­ tance in proportion to its specific gravity. The constituent parts of the artificial limb:

the

thigh piece, the shin piece, and the foot are cut out of solid seasoned wood, which is then hollowed either by hand or by machinery.

The limb maker produces a hollow limb

35 j # e . Hanger and Company, Ltd., Queen Mary's Hospital, Roehampton, England. 36 Martin,

0 £.

clt., p. 69.

37 Ibid., p. 48.

20 reproducing the external form of the thigh and leg. Occasionally these parts are carved from a single block. The workman tries to produce as perfect a fitting as possible, but this is not always easy.

Machines have been invented to

correct the internal form of the socket.

A needle follows a

cast of the stump, which is fixed on the machine, while a cutting tool reproduces exactly--theoretically at least--the curves described by the guide needle.

38

The constructor

hopes thus to produce a perfectly fitting socket, but the practical results have not always come up to the theoretical expectations.

In any case the socket, once made, is u n ­

changeable in the standard American wooden prosthesis.

If

the stump changes in shape or size the socket must be either altered or replaced, the latter being obviously the most desirable. The constituent segments of the limb are hollow, and the shell is rather fragile.

In order to strengthen the

whole limb American manufacturers have devised a covering of thin leather which is first soaked in water and then carefully glued on to the outer shell of the limb.

The constituent

segments of the artificial limb, the thigh and the foot, are connected by joints, the essential parts of which are metal.

39

38 Peterson, o£. cit.. p. 76. 39 Truax, Green and Company, Physicians and Hospital Supplies (Chicago; Truax, Green and Company, 1911), pp. 721-9.

21 The American limb is light, strong, and very mobile, it is clean and its upkeep is comparatively simple.

The

chief difference between it and the European prosthesis is 40 that it is more mobile and simpler. The knee joint is almost always fixed.

The American prosthesis marks a great

advance in the manufacture of artificial limbs, but it is not wholly above criticism.

Some amputees still prefer

appliances of the European type.

The most frequent objection

to the American limb is that the bearing on this prosthesis is hard and irritating for the stump; this is especially so in men with amputation below the knee.

American limb makers

have made marked alterations in the construction of their appliances.

The American limb maker is now making use of

plastics, a new material which will advance the limb industry many years.41 VIII.

CONSTRUCTIONAL MATERIALS

Leather was the first material used for the socket in the prosthesis itself.

The tanned leather socket was first

fashioned on a wooden mold and then held in place on the stump by leather laces. 40 Martin,

0 £.

The leather socket became saturated

ci_t•, p. 69.

41 Terminal Research Reports on Artificial Limbs. April 1, 1945 through June 30, 1947. (Washington, D.C.: National Research Council, 2101 Constitution Ave., N.W., June 30, 1947), p. 34.

22

with perspiration and threw off a very pungent odor.

Moulded

leather is a poor material to use for a socket, for it gets out of shape, is heavy, porous, readily absorbs moisture, gets dirty rapidly, is not washable, and soon rots. The wood socket, which appeared in the 1 8 0 0 fs, could be worked so as to relieve the tender area of the stump in the fitting process.

This material could be given an outside

wrap of thin skin which made it quite durable.

Inside the

socket a proper finish gives a glass-like surface that is 42 free from friction and is perspiration resistant. Tools were designed so that manufacturers could apply machinery to shaping the socket.

Changes can easily be made in a wooden

socket, thus simplifying the process of fitting and aligning. Wood can be worked by hand tools and the latest mechanical equipment can carve out the socket by machinery that will, with a pattern, match the human contours. wood are many:

The advantages of

its lightness in weight, its toughness and the

fact that it retains permanently the shape it receives from the limb m a k e r . ^ Some prosthesis are made of duralumin.

This is a

metal as durable as wood which offers a great advantage in its lightness and flexibility.

However, these factors are

42 Ibid.. p. 35. 4® Truax, Greene and Company, op. cit., p. 7S1.

23 not always to be recommended Tor scientific construction.

44

The disadvantageousness of metal was found to be in the denting, which caused the shape of the socket to change. Only the most skilled of tinsmiths could repair this damage successfully. The next introduction was the fiber prosthesis, with a wooden ankle base, and foot and knee constructed of metal. However, they did not lend themselves to alignment as well as wood or aluminum, nor were they found to be as durable. Plastics are still in the experimental stage.

45

The

work that has been accomplished and tested through a period of four years indicates that plastics have advantageous features over all of the other known materials on account of their lightness.

Their durability depends upon being re­

inforced with glass fiber or wire-netting for greater tensile strength.

Artificial limb testers have proven the hygienic

features of plastics since they can be washed with soap and warm water without material damage.

46

44 Technical Report - SDC 279-1-10, Investigations with Respect to the Design, Construction, and Evaluation of Prosthetic Devices (Port Washington, Long Island, New York: Office of Naval Research, Department of the Navy, 1949), 200 pp. 45 Martin,

0 £.

cit♦, p. 92*

Report of Amputees Appearing Before Congressional Meeting, Veterans Affairs Committee. Hearings before the Committee on Veterans Affairs, House of Representatives, 80th Congress, 2nd Session (Washington, D.C.: United States Govern­ ment Printing Office, May 11, 1948).

CHAPTER III THE DEVELOPMENT OP THE RESEARCH PROGRAM ON ARTIFICIAL LIMBS IN THE UNITED STATES OP AMERICA In July of 1943 in Washington, D.C., the Subcommittee on Orthopedic Surgery, Committee on Surgery, Division of Medical Sciences and the National Research Council, recommended that a temporary committee be appointed to cooperate with the United States Veterans Administration.

This recommendation

resulted in the formation of a “Panel on Amputations,” con­ sisting of Dr. Philip D. Wilson, Chairman; Dr. Harold Conn; Dr. Albert Key; Dr. Guy W. Leadbetter; and Dr. George K. Bonnet, Chairman of the Subcommittee on Orthopedic Surgery, ex-officio.

The first meeting of the Panel was held in

September of 1943 in Washington, D.C.^ Shortly after this meeting of the Panel the limb makers of the United States established the Research Institute Foundation,

Inc., to carry out research and development of

artificial limbs.

This meeting was held in New York.

While these conferences were being held the Army and the Navy had established brace shops and amputation centers on the Atlantic and Pacific coasts to take care of the ampu­ tation cases resulting from the combat areas of World War II. 1 Meeting held at the National Research Council Bldg., 2101 Constitution Avenue, N.W., Washington 25, D.C.

25 Early in 1944 an International Conference on Ampu­ tations and Artificial Limbs was called by Dr. R. I. Harris of the Department of Veteran Affairs, Ottawa, Canada. Thereafter, close cooperation was maintained between the Canadian and American research groups in the study of new artificial limbs* Later in 1944, the Northrop Aircraft,

Incorporated, of

Hawthorne, California, through its President, Mr* Jack K* Northrop, became interested in the problem of prosthetic design and began work on a wrist joint for an artificial arm, which was financed by the American Legion Auxiliary*

The

first wrist joint was fitted to Mr* Charles McGonegal on January 15, 1945, at Hawthorne, California*

2

The following month, February 1945, the Surgeon General of the United States Army, Major General Norman T. Kirk, requested that a permanent committee be named by the National Research Council and consequently the Committee on Prosthetic Devices, operating under the Division of Medical Sciences and the Division of Engineering and Industrial Research jointly held its first meeting in Washington, D*C. on March 26, 1945* The immediate initiation of the Committee on Prosthetic Devices made possible the activities and financing of the ^ The Northrop News, Hawthorne Field, Hawthorne, California, vol* 4, No. 10, July 4, 1945*

26 early projects by a grant of funds from the Office of Scientific Research and Development, Washington, D.C., in connection with the most helpful assistance of Dr* Vannevar Bush. The function of the Committee on Prosthetic Devices was the inauguration and administration of a program of research and development aimed at the improvement of artificial limbs*

3

The first concern of the sponsors of the

Committee on Prosthetic Devices program was directed toward the alleviation of the loss of limbs suffered by over

Organization of the Committee: For the purpose of administering a research and development program in the field of prosthetic and sensory devices, the National Research Council established the "Board for Pros­ thetic and Sensory Devices" under which there were two technical committees appointed: the Committee on Prosthetic Devices and the Committee on Sensory Devices* Within the National Research Council, the Division of Medical Sciences and the Division of Engineering and Industrial Research were responsible jointly for the activities of the Board for Prosthetic and Sensory Devices and for its two committees* Later the Board for Prosthetic and Sensory Devices was dissolved, permitting the Committee on Prosthetic Devices to report directly to the National Research Council* Later also the name of the Committee was changed to the "Committee on Artificial Limbs*" The National Research Council is a technical body within the National Academy of Sciences charged with the responsibility for "conducting research in mathematical, physical, and biological sciences and in the application of these sciences to engineering, agriculture, medicine, and other useful arts." The National Academy of Sciences and the National Research Council are quasi­ government agencies* Their research work is financed by the returns from endowment funds, by special grants, and by contracts with other agencies*

seventeen thousand veterans of World War II*

4

Amputations

have not been confined to military action alone*

It is

estimated that from twenty-five to forty thousand civilians lose limbs each year*

During World War II, insurance and

industrial papers reported that sixty-five thousand persons suffered major amputations in defense industries, a little over 3*8 times as many as were reported by the Armed Forces of the United States*

Furthermore the Committee on Prosthetic

Devices anticipated that the benefits of the research program would become availahle to all civilian amputees* The keen foresight, understanding, and material assis­ tance of Judge Robert Patterson, Under Secretary of War, in

4 Colonel Leonard T. Peterson, MC, Chief of Amputation and Prostheses Unit, Surgeon Generalrs Office, Report of European Observations, by Commission on Amputations and Prostheses, 1946, p* 18* Roehampton, England U.S. Army since since Sept* 1939-46 Dec* 1941-46 Total patients Total stumps

5,847 14,912 ____ 6,203______________ 15,993_________

Above knee 35.7 % 30.74 % Below knee 35.5 % 48.12 % Above elbow 13.4 % 10.40 % Below elbow 15.3 % 10.70 % Double amputees 06.4 % 07.10 % Triple amputees 00.017 (1) % 00.06 (9) % Quadruple amputees 00.017 (1) % 00.013(2) % * The total number of amputees was on a basis of 1949 Veterans Administration file count. 5 Amputations of major types totaled 2,767 in 2,612 amputees cared for at McCloskey General Hospital from March 6, 1943 to February 1, 1946. Of these amputations, 70 per cent were of the lower extremity and 30 per cent of the upper. The 1948 Yearbook of Orthopedics and Traumatic Surgery, pp. 361-

28 the undertaking of the Committee on Prosthetic Devices greatly encouraged the Committee personnel and added the Department of the Army to the project• The Department of the Navy through the Bureau of Medicine and Surgery headed by Rear Admiral Ross T. McIntyre, MC, U. S. Navy, closely coordinated the research work of the U. S. Navy with that of the Committee on Prosthetic Devices. The U. S. Navy amputation center on the Pacific coast, located at the U. S. Naval Hospital, Mare Island, California, and the Atlantic coast center located at the U. S. Naval Hospital, Philadelphia, Pennsylvania, assisted the Committee on Pros­ thetic Devices materially. The immediate objective of the Committee on Prosthetic Devices was the development of designs and specifications upon which procurement by the government agencies could be based.

This was cited by the Committee on Prosthetic Devices

to be:^ 1. To assist the U. S. Army, the U. S. Navy, the United States Veterans Administration, and other Government agencies concerned with the rehabilitation to meet the present emergency by the early procurement of the best prostheses now obtainable. 2. To initiate and carry on a research and develop­ ment program with the ultimate objective of providing the best possible artificial legs and arms, particularly for those who have sustained loss of these members in

® Research Reports on Artificial Limbs, First Annual Report, Committee on Prosthetic Devices of the National Research Council, Evanston, Illinois, April 1, 1946. 47 pp.

29 war; as a generally structure as may be

concomitant, to develop artificial limbs to a high degree of excellence in design, and performance, with such standardization practicable.

The Committee on Prosthetic Devices proceeded toward its objective in the following manner that proved to be quite acceptable by not only the Military Departments of the United States, but also by the commercial limb manufacturers throughout the United States: 1* By making a thorough study of existing prostheses and by an analysis of their mechanical features. 2. By conducting basic analytical studies of the mechanical behavior of both human and artificial limbs when performing their customary human functions. 3. By establishing, in the light of information obtained by procedures 1 and 2 a research and develop­ ment program directed towards the improvement, simpli­ fication, and, so far as practicable, standardization of the design and construction of artificial legs and arms • 4. By conducting studies of materials and methods of fabrication, special structures, and mechanisms. 5. By studying the art of fitting with a view to simplifying and standardizing procedures and insuring the best possible adaptation of the prostheses to the requirements of the amputee; by correlating the work of the orthopedic surgeon and the limb fitter. 6. By considering the problem of training the amputee in the use of his prostheses.^ Prior to the foundation of the research project under­ taken by the Committee on Prosthetic Devices, research was conducted by the individual artificial limb companies. 7 Ibid., p. 15.

The

30 findings of a large number of these commercial companies in the United States and Canada revealed that the three major items of importance had to be undertaken by the Committee on Prosthetic Devices before work on the problem of research Q

could be started* A collection of artificial limbs had to be acquired to study existing artificial limbs of all description. Sample limbs were to be obtained from commercial limb manu­ facturers, from the U. S. Army and U. S. Navy, and from various other private sources in the United States of America and abroad.

The purpose of acquiring these appliances was

to enable the committee engineers to make technical studies and mechanical patterns of the walking track of the appliance, and extract the features that merited study and research. The next point to

bemetby

Devices was the establishment of

theCommittee

9

onProsthetic

a reference library.

This

library was planned to contain books, magazine articles, and private papers on the subject of orthopedic and artificial limbs.

Microfilm copies were to be made of source material

for use in supplying background information to contractors working for the Committee on Prosthetic Devices.

English

translations were made from references published in various foreign languages.

This unique library held material in a

8 Ibid., p. 16. 9 Ibid.. p. 27.

31 classified system which enabled the project engineers to obtain any reference for a check with theories to drafting table.

It also made available to the orthopedic surgeons

the problems met by the limb fitter and assisted in advancing the study of amputations by opening new material.

The head­

quarters of the library were in the National Research Council 10 Building, Washington 25, D,C. The third and most important item on the agenda of the Committee on Prosthetic Devices was the establishment of a patent file.

This library unit would assist the Committee

on Prosthetic Devices members and engineers on the projects throughout the United States and Canada.

It provided historl

cal background of the artificial limbs in present day use. The library also served as an aid In anticipating possible patent situations arising out of the work of the Committee on Prosthetic D e v i c e s , ^

The total list of patents collected

by the Committee on Prosthetic Devices numbers well over a thousand. Prom all the evidence that could be gathered, the Committee on Prosthetic Devices reached the analysis of the problem as classified in the following outlines 1,

General Problems: a. Weight b* Maintenance

10 Ibid. , p. 16.

11 See Appendix C, Letter from Department of Ju3tice.

32 c. d. e. 2.

Susceptibility to moisture Noise in the prostheses Pitting

Specific Problemss a. Upper Extremity (1) Elbow (2) Wrist (3) Utility hook (4) Cosmetic hand (5) Limb sections and sockets (6) Attachments and controls (7) Use of auxiliary power b. Lower Extremity (1) Knee joint (2) Ankle joint (3) Foot (4) Structural designs (5) Structural materials (6) Attachments 12

Among the mechanisms, the problems of the knee and hand were the most formidable.

The questions of fabrication

and materials were naturally overlapping, since it was necessary to find materials of great strength, but with a quality of lightness.

The choice of materials was obviously

dependent upon the tools, equipment, and skills required for fabrication, particularly in connection with those parts needing adjustment to the individual patient#

Leather, wood,

and metal have been used in making artificial limbs, and in recent years Duralumin has been widely employed.

Laminated

plastics appeared to be an excellent solution to the problem, and evaluation studies were started by the Committee on Prosthetic Devices in June of 1945# 12 Eugene P. Murphy, Report to Committee, Staff Engineer of the Committee on Prosthetic Devices, 1946.

33 Fundamental Information was needed on the motions of joints; forces encountered in walking and under occupational conditions,

statistical distribution of sizes of body parts,

and forces and motions most often employed in daily life. To be regarded as a human being and not regarded as a disabled person lifts an amputee from the mental depths of depressiveness to the high level of an active creative strata of life.13 The basic problem was summarized by an engineer of the Committee on Prosthetic Devices:

14

The most important points to consider in the design of any prosthetic device are, the proper balance, weight, function and appearance. Clearly, an excessive develop­ ment of one point at the expense of the others will defeat the entire purpose. For example, a hand per­ mitting all the individual movements corresponding to the human joints would be so heavy that no one would wear it. In order to learn the latest developments in the artificial limb industry, most of which had taken place in Europe, the Surgeon G-eneral of the United States Army appointed a commission, on March 4, 1946, to travel to Europe to study amputation techniques and prosthetic devices in Scotland, England, France, Germany, Switzerland, and

13 Henry H. Kessler, "Rehabilitation of the Amputee,11 United States Naval Medical Bulletin. 44:1197, No. 6, June, 1945. Eugene F. Murphy, Staff Engineer of the Committee on Prosthetic Devices.

34 Sweden.

15

Much valuable information was gathered on this

tour, particularly the technique of the so-called cineplastic surgery as first used by Dr. Sauerbruch of Berlin and later improved by Dr. Lebsche of Munich, and the suction socket method of fitting above-knee artificial legs. Although much had been written about the cineplastic method, there was little encouraging evidence that this method was practical until the members of the Commission saw the results of the work of Dr. Max Lebsche in Munich, Germany, a former student of Dr. Sauerbruch.

Dr. Lebsche had developed

improvements in the selection of cases, location of the tunnels, and surgical techniques which resulted in improvement of function of the muscle motors.

16

The cineplastic prosthesis was in the crude experi­ mental stage, and the hand had only the function of the pinch movement, the over-all results were impressive, chiefly 15 Commission was composed of the following: Colonel Leonard T. Peterson, MC, Chief of Amputation and Prostheses Unit, Surgeon Generalfs Office. Dr. Paul E. Klopsteg, Chairman, Committee on Prosthetic Devices, National Research Council. Lieutenant Colonel Rufus Alldredge, MC, Chief of Amputation Section, England General Hospital, Atlantic City, New Jersey* Mr. Edmond M. Wagner, Executive Assistant, Committee on Prosthetic Devices, National Research Council. Lieutenant Colonel Robert G. F. Lewis, Ordnance, Amputation and Prostheses Unit, Surgeon GeneralTs Office. S/Sgt. John Paul Gavell, Recorder. Henry H. Kessler, Cineplasty (Springfield, Illinois: Charles C. Thomas Company, 1945), 201 pp.

55 because of the unusually good function of the muscle motors* It was the opinion of the members of the Commission that if the prosthesis could be correspondingly improved, the cine­ plastic method, using Dr* Lebschefs surgical principles, would be suitable for trial in the United States in certain selected upper extremity amputees*

The United States Army

research laboratory at Forest Glen, Maryland, in July 1949, developed a vastly improved artificial hand*

17

Dr* Rufus H* Alldredge, MC, Chief of Amputation Section, England General Hospital, spent some weeks with Prof* Lebsche studying all phases of the surgery and pros­ thesis*

One of each of the various types of prosthesis were 18 obtained for further study in the United States. Arrangements were made with the Allied Military Governors for German cineplastic amputees to visit the United States for the purpose of working with the various contractors of the Committee on Prosthetic Devices throughout the United States on improvement of the cineplastic methods and prosthesis. The following is a list of the contractors under the Committee on Prosthetic Devices programs Northrop Aircraft, Inc., Hawthorne, California. Goodyear Tire and Rubber Company, Akron, Ohio. 17 Major Fletcher's Report, Life, August 1, 1949. 1® Rufus H. Allredge, The Cineplastic Method in Upper Extremity Amputations, Committee on Prosthetic Devices, Room 355, Northwestern Technical Institute, Evanston, Illinois, 1947.

36 Research Institute Foundation, Appliance and Limb Manufacturers of America, Detroit, Michigan* University of Southern California, Medical School* University of California, Berkeley, Medical and Engineering School* United States Plywood Corporation, New Rochelle, New York* International Business Machines Corporation, Endicott, New York. Northwestern University, Mechanical Engineering Department, Evanston, Illinois* National Research and Manufacturing Company, San Diego, California* A* J* Hosmer Corporation, Los Angeles, California* C* C* Bradley and Son, Inc., Catranis, Inc*, Syracuse, New York* University of California at Los Angeles, Engineering Department, Los Angeles, California. Mellon Institute of Industrial Research, Pittsburgh, Pennsylvania* Adel Precision Products Corporation, Burbank, California* Sierra Engineering Company, Sierra Madre, California* Armour Research Foundation, Chicago, Illinois*

CHAPTER IV THE NORTHROP AIRCRAFT, INCORPORATED, ARTIFICIAL LIMB RESEARCH DEPARTMENT 96, PROJECT 17 The story of Northrop Aircraft*s Project 17 is the story of how aircraft designers and mechanics, at the request of the United States Army Medical Corps, turned their know­ ledge and the facilities of their specialized field to aid in the development of artificial arms and legs for service amputees of World War II. Northrop Aircraft*s well-known Black Widow project at the Birmingham Hospital was visited by specialists in ortho­ pedic and amputation cases for the United States Army's 9th Service Command, with headquarters in Fort Douglas, Utah. Dr. Loutzenheiser was keenly aware of the needs of the World War II

veterans confronted with the loss of an arm or leg#

Thisneed for a

better artificial appliance to fit the

returning veteran was the paramount motivation that led Dr# Loutzenheiser to the organizer of the Birmingham Hospital project, Mr# James L. McKinley.

l

Dr. Loutzenheiser1s plans

and ideas were of great interest to Mr. McKinley who realized that the aircraft industry could aid materially in the quest

1 On leave from Northrop Aircraft, Hawthorne, Calif­ ornia, to Birmingham Army Hospital, Van Nuys, California, to coordinate hospital project (Birmingham Plan, Department 99).

38 for better artificial limbs.

Northrop Aircraft, with its

modern facilities and technical knowledge of modern mechani­ cal methods and material applications, would be a logical base to work from in such a research project* Mr* McKinley arranged a meeting for Dr* Loutzenheiser with Mr* John K* Northrop at the Northrop Aircraft Companyfs Hawthorne, California, office*

Mr* Northrop being a leader

in the development of efficient light-weight mechanical devices and in the use of strong but light material in air­ craft seemed the logical engineer.

Since he was already

interested in the problems of the handicapped, his reply was in the affirmative and that Northrop Aircraft would undertake with pleasure and vigor the project. This was indeed a new field of research for aircraft; the first act of the new project was to appoint one of the Engineering Department’s best gadgeteers, Mr. Mike Nagy, to head the research and development work. in Mr* N a g y ’s converted garage workshop.

Project 17 started Mr. John T.

Willoughby of the Engineering Department contributed his own spare time, advancing ideas and designs for an arm control. Mr. Don Threewith, also of Engineering, draughtsman and detail man for the project, contributed ideas and designs for the arm control.

Mr. Northrop guided all of these efforts.

The first job was to develop a more efficient and more durable control of the existing artificial hand or hook.

39 Leather thongs had

been the best control available for years.

Tests showed these

leather cableunits lasted from two

three months; thus

there was the expense of periodical cable

replacement due to

friction which caused cable breakage*

to

The

stretch and variation in the length of the thong in various arm positions made deft control of the artificial hand impossible.

This type of cable had been the best yet

developed and to replace this unit would take weeks, even months, of hard work. The first arm test pilot was Lieutenant Thomas R. Russell, U. S. Army, who was fitted with the first Northrop cable control.

The present Northrop Control has been rigor­

ously proven and has passed all tests with entire satisfaction. It consists of a 1/16 inch diameter stainless steel flexible aircraft cable, housed in a special flexible stainless steel housing, and provided with light-weight terminal fittings and supports for attachment to the artificial arm and hand.

This

completely eliminates any appreciable stretch or variation in control length with different arm positions, transmits 80 per cent of the applied force to the hand, and should give 2 comparatively long wear. Dr. Loutzenheiser was aware that the commercial limb industry had been toying with the idea of making a more 2 The Northrop News, Northrop Field, Hawthorne, California, vol. 4, No. 10, July 4, 1945.

41 suitable artificial arm and hand and even with meager funds had attempted to correct many of the malfunctions and repeated breakdowns found in the present day prosthesis.

But

the industry had been too small and too highly specialized to become fully acquainted with the latest improvements or to support the high cost of a research project required to keep prosthetic devices on a par with other technological develop­ ments.

It is doubtful that any extensive prosthetic research

would have been carried out in private industry without financial assistance such as was supplied by the Federal Government.

The engineers could provide the drawings, but

skilled mechanics and machinists with extensive tools and a knowledge of plastics and metals were required.

This,

combined with a practical background and experience in working with light-weight materials, was important in the choice of the personnel for the expansion of such a project. Early in 1945, laminated plastics were introduced for the fabrication of sockets for below-knee amputees and later were applied to the structural sockets of artificial arms, with the result that a light-weight, strong, durable, and sanitary unit could be produced in quantity at a very low cost. On June 15, 1945, the Committee on Prosthetic Devices negotiated a contract with the Northrop Aircraft to begin a

42 full scale research program.

3

Mr. John K. Northrop selected

Mr. Meyer Fishbein, a Northrop aeronautical research engineer, to head a group of engineers in establishing the desired project for the study of prosthetic devices.

The established

Northrop Aircraft Company offered many young engineers and draftsmen, whose services could be utilized in such a project, to sharpen their future potentialities as researchers. The research laboratory for the prosthetic study was in an especially acquired building located at 244 South Hawthorne Boulevard, Hawthorne, California.

Special power

machinery was moved from the main Northrop plant, about a mile away, to the new site.

In October, 1946, the research

building was divided into a receptionist fs area, engineer's office, drafting room, fitting room with a walking ramp, steps, and mirrors for experimental and testing purposes. The plaster cast room, plastic research laboratory, and the machine shops were fitted with the latest mechanical equipment. Engineering Project 17 began on August 10, 1944, with the Project Engineer, Mr. Mike Fishbein, and his engineering staff of five design engineers, one draftsman, and two plastic engineers.

g

One design engineer was assigned to the

3 This research program was Department 96, Project 17, Restricted to Unauthorized Persons. 4 Northrop Aircraft was undertaking secret U. S. Army research projects. These projects required skilled technicians. 5 See Appendix A.

study of lower extremity prosthesis, one to the study and design of above elbow prosthesis to be actuated by means of a small hydraulic system, and one to the development of auxiliary electrical means of actuating the upper extremity prosthesis• The shop crew consisted of seven men:

four were

assigned to machine operations and bench assembly work associated with the execution of designs produced by the engineering department; two devoted their entire time and efforts to fitting of harnesses, taking of stump impressions by plaster wraps, and the fitting of appliances to test amputees; one was engaged in making the plastic forms and molds that were required for the low pressure lamination of plastic limb sections.

6

The medical staff of Northrop Aircraft assisted the engineers with X-rays of socket fitting and furnished skeletons for the use in drawings and other data required for the research project. Dr. Irving Rehman, Consultant and Director of the Research Program on artificial limbs at the University of Southern California, gave lectures to engineers and amputee limb testers and held lectures In the laboratory where dissections of human legs and arms were conducted.

6 See Appendix A.

This

44 background assisted the limb Titter, moulders, engineers, and amputees testing the new limbs, to gain a fuller knowledge of the research problems.

With this excellent

training the project reports contained a much more realistic coverage of the problems confronted by the engineer and the amputee•^ I.

ARTIFICIAL ARMS

Like all products of modern industry and science, artificial limbs are subjected to constant improvement. Expert engineers who already had the knowledge of kinesiology which is the study of the complex means by which natural arms and legs operate, needed to marshall ingenious scientific material devices to duplicate as nearly as possible the normal motions in artificial limbs.

Most of these engineers,

however, were frank to admit that problems presented by the human body such as stress and other complicated engineering problems were more exacting than problems presented by machines. It was a known fact that cosmetic hands available to amputees were of almost no practical value while the hook was

? A weekly conference was held between the amputee device tester and the project engineer to analyze failures of the mechanical parts or areas causing pain to the stump. These reports would be written up and logged in the amputee*s file as a guide in correcting the new device.

45 a most useful device.

Many believed that some of the value

of the hook could be combined with the cosmetic glove to produce a social hand and a useful occupational hand.

The

purpose of this social hand would be to enable an amputee to meet the normal social life without the embarrassment that is usually experienced by the wearer of a hook or other seemingly unsightly contrivance in public places.

8

A good hand must be simple and rugged in design and provide an independent, positive control of all movements. The hand should provide a suitable compromise between picking up articles and holding them in a useful manner; such a hand should enable the amputee to handle money and other small objects that are required in daily life.

This challenge

convinced the engineers that the hand should be so fashioned that the amputee could go into a restaurant or other public place and order food and drink and not be conspicuous.

The

plans called for an upper extremity artificial limb of light-weight material consistent with the strength requirements. The limb also should have its mass located to produce the smallest possible movement of inertia for supination; the hand should be covered with a suitable cosmetic glove that would provide the wearer with an ample service life, at a reasonable price.

® Abstract of minutes, Subcommittee on Hands, Conference Reports, Washington, D.C., April 14-18, 1947, 85 pp.

46 The first specific project undertaken by Northrop Engineers of Department 96, Project 17, was a below-elbow prosthesis which was started on November 13, 1944*

This

prosthesis would provide a rotating wrist mechanism that could be operated by the rotation of the forearm and was closely designed from the study made by Dr. Rehman, who pointed out that of the three nerves (ulnar, radial, and median) controlling the muscles operating the hand, the ulnar controls the finer motions, and the radial and median the coarser or prehensile movements.

Hence, the movements

provided by all muscles controlled by the ulnar nerve could be set aside and only those motions produced by muscles con­ trolled by the radial and median nerves need be considered. The number of tendon cords were counted and their functions noted.

This information was used to give a rough idea of

the proportionment of cord functions for hand designs using more than one operation cord. The design of the prosthesis in its present form consists of a planetary gear with a system of locking rollers attached to a plastic socket.

The rotation of the stump is

transmitted by the plastic cuff to the driving mechanism and through the planetary gear system to the driver or load end of the wrist unit. freedom of rotation.

Three sets of ball bearings provide The unit device is made of light-weight

duralumin and plastic, with the exception of the ball bearings,

BELOW ELBOW AMPUTATION PROSTHESIS T D es/ gned An d Developed DEPAR TM EN T OF

WRIST DISARTICULATION PERMITTING FOREARM

b y Nobthbop A/b c pa ft , PR-OSTHESIS DEVELOPMENT

I nc . rs

PROSTHESIS ROTATION

WRIST MECHANISM CONTROLLED BY FOREARM ROTATION — PLASTIC MODEL

MODEL OF OPERATING PRINCIPLE OF ROLLER CLUTCH LOCKING SYSTEM

WRIST MECHANISM WITHOUT ROLLER CLUTCH • LOCKING SYSTEM --EXPLODED VIEW m

^ ^

STANDARD WRIST MECHANISM 4 kEXPLODED VIEW SHOWING PLANETARY STEP-UP Q GEAR SYSTEM DRIVE AND LOCKING ROLLERS

STANDARD WRIST MECHANISM CONTROLLED BY FORE .ARM ROTATION, ROTATION OF WRIST CAP 2 3 4 X ROTATION OF FOREARM WITH IRREVERSIBLE • ROLLER CLUTCH LOCKING SYSTEM

48 planetary gears, and locking rollers.

The driven end of the

rotating wrist is constructed so as to receive a standard utility hook, a dress hand, or other prosthetic appliances.

q

The goal that was set included an efficient and durable control mechanism for the existing artificial hand or hook with the new wrist joint permitting direct rotary control of the hook for the first t i m e . ^ forecast future improvements.

This initial development The light-weight and sanitary

plastic sockets made possible better socket fittings, as well as long life and easier maintenance of the prosthetic device. From months of drafting board theory the second set of artificial limbs was ready to be tested by an amputee volunteer.

Mr. Charles C. McGonegal was fitted at Northrop

with the first pair of below-elbow arms on January 15, 1945. Mr. Lonnie Carberry began to test the first pair of above­ elbow in the same month.

The comment of both volunteer

testers was that the rotating wrist developed by the project engineers greatly improved the dexterity in manipulation of the driving end of the device.

This praise for such a small

change in the design of a prosthesis gave such satisfaction to the engineers that they worked willingly and very

9 The amputee could change the utility value of his appliance by adjusting a hook or the "synthetic skin" cosmetic glove hand for dress wear. 10 Edmundo Vasconcelos, Modern Methods of Amputation (New York: Philosophical Library, Inc., 1945), pp. 235-6.

49 enthusiastically on other features to improve the artificial arm.

11

II.

ARTIFICIAL HANDS PROJECT DEVELOPED BY THE SIERRA ENGINEERING COMPANY UNDER NORTHROP AIRCRAFT INCORPORATED

On July 15, 1946, Northrop Aircraft negotiated a second tier subcontract

12

with the Sierra Engineering Company

to design and develop an improved artificial hand which would combine functional usefulness with lifelike appearance.

This

development was directed toward cineplastic amputee appli­ cations, but could be made suitable for use by all other amputees by simple modification. A simple mechanical hand was first fabricated to be used as an aid in determining the mechanical problems involved 11 Public Relations Department, Northrop Aircraft, Inc., Hawthorne, California. Northrop-designed artificial arms with their special elbow joints have added many new capabilities for Lonny Carberry, a bilateral above-elbow amputee. The elbows can be locked instantly, in an almostinfinite variety of positions, allowing the amputee to open and close his hooks with ease. Here Carberry, having extracted a cigaret from his package, restores the pack to his pocket and releases the hook. This gesture would be extremely difficult for an amputee wearing the old-type artificial arm, which is considerably heavier and has an elbow joint locking in only a few positions. The Northrop non-stretching metal cable control to open the hook also makes this artificial arm easier to use, since no power is lost in stretching or friction. 12 Northrop had the primary contract (1944) with the Committee on Artificial Limbs.

51 in artificial hand design.

Prom this, a series of four hands

were developed, two being purely developmental but the last two of such advancement as to be considered of general value to the over-all prosthetics development program. In addition, auxiliary mechanisms such as force multi­ pliers, sense of touch devices, wrist disconnects, and miniature chain for use in force multipliers were investigated, designed, and tested* Later, on February 28, 1947, the Vard cineplastic arm subcontract with Northrop was terminated, and the design and development of an above-wrist prosthesis for use by cineplastic amputees was turned over to Sierra. Since specific physical physiological, and mechanical data required for design guidance was not available, it was necessary for Sierra to initiate an informal investigation to obtain these facts.

Formal data became available later

as a result of the project carried out by the University of California under the Committee of Artificial Limbs, but these data were not received in time to be used by the Sierra Engineering Company.

13

The factors stressed in the development of a hand were usefulness, appearance, and reasonable cost*

Other important

objectives considered were weight, moment of inertia about 13 Attendance at November, 1946, Symposium, held in the Engineering Materials Laboratory, University of California, Berkeley, California, November 16, 1946. See Appendix D.

52 rotational axis, service life, maintenance and repair, and interchangeability of parts* Included in the preliminary studies, and continued throughout the duration of the project, was the evaluation of existing commercial hands, the study of anatomy, and physiology of the hand and arm, together with the details of the cineplastic operation, and a review of previous prosthetic art*

Here, as in other projects of the artificial limb

research program, it was recognized that the engineer and surgeon must work together with a common understanding of the problems involved, if an improved prosthesis is to result from their efforts. In the beginning, an attempt was made to treat the problem of the hand separately from that of the arm, but as the work progressed it became more and more apparent that the hand and arm were an intimately related problem.

The function

of the arm is to place the hand where it can perform neces­ sary tasks, and the adaptability of the arm can greatly affect the usefulness of the hand design. performance became the important factor*

Hence, the combined This required an

evaluation of the normal movement of the wrist and arm, which indicated that a simple hand on an arm with a given degree of flexibility and independence of control could out-perform a more flexible hand placed on a less mobile arm.

54 Basic design requirements - hand.

Study of the force

required at the finger tips to hold common objects, and the maximum pull available throughout the length of excursion of the muscle tunnels, indicated that in an artificial hand designed for social uses the forces of the finger grip should be strongest when the fingers were nearly closed, to provide a firm grip on pencils, eating utensils, etc.

The success

or failure of the cineplastic type of prosthesis therefore would depend largely on the proper matching of the muscle pull-excursion characteristic with desirable fingertip grip throughout the arc of finger travel.

The biceps and pector-

alis muscles provide the strongest motors and it was noted that for a portion of the distance of travel or excursion, the maximum pulling force obtainable is essentially constant. Beyond this point, the pulling force of the muscle drops off rapidly.

Characteristic curves of the flexor and extensor

muscle tunnels tested at the University of California showed a sharp drop in available pulling force beyond a 1/2 inch excursion.

To best use these muscle tunnels within their

capabilities, an auxiliary force multiplying mechanism was indicated.

It was the consensus of opinion that only one

third to one half of the maximum muscle pull should be used as the design value for the operation of a prosthesis. Otherwise, early muscular fatigue and lack of control would prevent the continual use of the prosthesis.

ABO VE d

ELBOW AMPUTATION PROSTHESIS

An d Developed b y A /oxr//PO P A /r c r a ft , I n c .

ARTM ENT

£

OF PROSTHESIS

ELBOW LOCKING MECHANISM .WITH UPPER ARM TURNTABLEC £ FOREARM YOKEATTACHED

ELBOW LOCKING M ECHANISM £ PLA STIC MODEL

MODEL O F MECHANICAL PRINCIPLE OF OPERATION OF ELBOW LOCKING MECHANISM

V,

tin

Yr

t ; ,

Ah!,,* tl'J. 1

■

• i i n| & .. | *.

K g * f gi

PtK- • . 8 , *

I

r

DEVELOPMENT

INTERNAL COMPONENTS O F ELBOW LOCKING M E C H A N IS M EXPLODED VIEW **

56 A lock was found to be a very important part of the mechanical components of a hand as it permits objects to be held over long periods of time without tiring the muscles, and adds force to the grip when holding objects that cannot be satisfactorily held by the use of the power in the muscle tunnels alone.

14

It was decided to operate the hand by an internal push-pull rod as this would allow the entire mechanism to be enclosed in the hand envelope, and would be more effective mechanically than an external operating system*

A push-pull

rod with a 1/2 inch travel was established as a result of study and experiment, and this measurement was later con­ firmed by the Standardization and Simplification Subcommittee. A wrist-disconnect joint was designed to permit an amputee to change from a hand to a hook at will*

Resulting

discussion and study indicated that the wrist section should be elliptical for good appearance; when mechanical pronation and supination is required, the plane of the supinationpronation joint should be located approximately two inches back of the wrist-disconnect members; when the central pushpull rod is used to actuate the hand, the mechanism joining the internal push-pull rod to the external power transmission means should be located above the supination-pronation joint 14 Light-weight material was required for the locking mechanism to prevent fatigue in the operation of the arm appliance.

58 in the arm* Next, the question of grip was considered and it was found that the palmar opposition grip was the most desirable* The exceptional grasping and holding ability of this grip is due to the large contact area between the thumb and the opposing fingers, obtained by shaping and articulating the hand to approximate the effect of a three-jaw chuck.

The

fingertips of the index and middle fingers, contrary to what is normally expected, opened as the hand closed, but only at a rate sufficient to maintain the desired relative vise or chuck-like position between the gripping surfaces of the thumb and these fingers.

The ring finger and little fingers

were fixed to keep them consistently out of the way.

They

were located at the midpoint in the travel of the index and middle fingers and approximated the flexure of these same fingers when they were in this mid-point of their travel* Arm.

The mechanical arm development was originally

undertaken by Vard, Inc., under the supervision of Mr* William Shallenberger with as its objective the production of a new above-wrist prosthesis specifically for the cineplastic amputee, both above and below-elbow, with operational power supplied by cineplastic muscle tunnels or by a combi­ nation of muscle tunnel and harness* A brief study was made of the various motions of which the natural arm and hand are capable.

It was recognized that

59 it would not be reasonable to provide all of these motions in a prosthesis, so the most important were considered neces­ sary and assigned individual power sources, the less important were assigned individual power sources if practical or given passive motion, and the least important were eliminated* Wrist flexure had not previously been considered an important motion but discussion at a Symposium on Arms and Hands in February, 1947, indicated that it should be provided* It was determined that active control of wrist-flexure is not required at all times, and that passive flexure, in which the degree of flexure can be pre-set and locked by the amputee, is satisfactory.

Abduction and adduction of the wrist were

not considered sufficiently important to warrant additional complexity of the prosthesis. Pronation and supination (rotation of the hand and wrist about the longitudinal axis at the forearm) was con­ sidered highly desirable, either passive with a positive lock to prevent inadvertent rotation under load, or controlled by a shoulder harness. should be provided.

In any case, a full 180° of rotation 16

Elbow flexure, of course, was considered one of the

15 Meeting of members of the Northrop staff and the Committee on Prosthetic Devices held at Northrop Research Laboratory, Hawthorne, California, February 10, 11, and 12, 1947. 1® This amount of rotation provides the amputee with full latitude to perform his daily tasks.

15

60 most important motions to be provided and warranted an individual power source. It was assumed that the maximum o flexure required is 135 from the fully extended position. That is, when fully flexed, the forearm should form an acute angle of 45° with the upper-arm. Rotation on axis of the upper-arm--that is, the ability of the upper arm to rotate through an angle of approximately 90° about the axis of the upper arm through the shoulder and elbow, was considered essential to permit the amputee to adjust his clothing and perform other activities close to or at some distance from the body. Muscles available for use as motors.

In the forearm,

It is possible by the cineplastic technique to group roughly the muscles at the medial side of the arm and insert a skin tunnel to adapt them as one muscle-motor designed as the "flexor11 motor.

Likewise a motor at the lateral side would

be used as an extensor motor.

It is reported that such

motors might be expected to have a force of fifteen to twentyfive pounds and an excursion of 1.5 - 2.0 cm.

Dr. Alldredge

17

has stated that the minimum length of forearm required for satisfactory use of these muscles for muscle-motors is approximately 10 cm. measured from the insertion of the biceps. 17 Lieutenant Colonel Rufus Alldredge, MC, Chief of Amputation Section, England General Hospital, Atlantic City, New Jersey, 1946, Report of European Observations, by Commis­ sion on Amputations and Prostheses, 1946.

61 In the upper arm, two muscles are available for cineplasty; the biceps on the front and the triceps in the rear.

The same reference gives the biceps a force of forty

to fifty pounds and an excursion of 5 - 7 cm. and for the triceps, fifteen to twenty-five pounds and 1.5 - 2.0 cm. The triceps are naturally used to produce extension of the elbow, and Dr. Alldredge has stated that in his opinion it is possible to insert a tunnel without destroying that function. In addition to the muscles in the arm itself, the pectoralis major, which starts with insertion at the shoulder and spreads over half the chest, lends itself well to cine­ plasty.

This muscle has a force of forty to fifty pounds

and a travel of 5 - 7 cm. Hand design.

Hand No. 1 was built to be used for

preliminary design exploration and generally followed the structure of the human hand, incorporating the same skeletal structure and pivotal joints.

Space was provided within the

metacarpal members of the structure to house a "whiffle-tree?l type of force-equalizing mechanism.

The hand was operated

by flexible metal cables and the knuckle joint details were similar in shape to those of the natural finger.

As this

hand was never intended to be used as a prosthesis, weight and appearance were not considered in its fabrication.

62 The hand was so constructed that various mechanical details could be tried, and from a series of experiments the following facts were established: 1.

All movements should be positively controlled.

2.

All joints should be as free of friction as possible.

3.

In all moving joints the friction moment arm should be minimum--that is, the bearing pins should be as small in diameter as possible consistent with the materials used and the bearing loads.

4.

Mechanism parts that stretch in service and there­ fore require take-up adjustments are undesirable and should be avoided*

Hand No. 2 was built to provide an experimental hand which would demonstrate the independent use of two muscle tunnels in a prosthesis.

It was built by revising one of the

German amputeeTs spare arms*

18

Provision was made for the

actuation of the finger group by one muscle tunnel and the actuation of the thumb by another muscle tunnel, and changes were made in the palm shell to permit an enlargement of the interior cavity and increased hand opening.

It became apparent

from this experimental hand that a forearm prosthesis using 18 One of the most common features of the prosthesis was that the main structure consisted of two metal straps, one on each side of the prosthesis. The elbow hinges in the straps were of the offset rather than the clevis type. Leather was utilized for a cosmetic purpose and offered no structural function. This type of construction appeared to be at least thirty years old.

63 two muscle tunnels independently requires a separate means of holding the prosthesis in place.

Sierra did not reduce

to practice the information learned by this experimental development. Hand design 3A.

Since the Committee on Artificial

Limbs needed hands for American amputees who had volunteered for the eineplastic operation, the third hand was developed to provide a hand whose functional values would be equal or superior to the Hufner hand (the hand used by the German amputees).

The Hufner hand was not duplicated because its

service life was not satisfactory, the fingers could be opened only a little over an inch, and the leverage system was so arranged that there was a very low fingertip force available as the hand approached the closed position. The Sierra 3A hand had fingers and thumb articulated at the proximal and distal joints, and the thumb was in direct opposition to the second and third fingers*

The frame,

which held the operating mechanism and necessary bearings for the thumb and finger groups, was made of aluminum alloy sheet metal.

The frame also supported a laminated plastic skin

shell.

This design proved to have adequate strength for

normal usage and was effective in picking up articles as small as paper matches and as thin as dimes.

Four right

hands were made and as they were made various means of

64 reducing weight were used

19

until the weight was reduced

from fifteen ounces to nine and one half ounces. Hand design 3B.

From the experience gained in the

design and construction of the 3A hands, improvements were made in the general mechanical and structural design as well as in the lock mechanism.

The hand was built from a sculp­

tured shape and the articulated finger joints were made of ball and cone fittings rather than the "tongue and groove" type.

This resulted in fewer parts and produced a smoother

exposed surface throughout the complete angle of movement. The fingertips were first given a fully rounded shape as found in the natural finger, but, while it was found that the holding ability had been materially increased, the fully rounded fingertips were not suitable for picking up an object the size of a pencil from a flat surface.

Subsequently,

rubber pads were cemented in recesses at the fingertips to increase the friction, and this was found to increase the ability to pick up and hold small objects. Hand 4A.

The purpose of hand 4A was to produce an

improved hand suitable for manufacture, incorporating design features found to be of value from the experience gained in 19 Steel pins made hollow, steel parts reduced in size, bronze bushings reduced in wall thickness, aluminum parts made thinner and unstressed portions removed where possible, magnesium substituted for aluminum.

2106 4 * 0 5 7 NORTHROP HAND; MECHANICAL, MODEL 2. PR0J.I7

66 the design, construction, and use of earlier hands. After a tentative design was established, and before engineering and manufacturing time was spent, an experiment was made to endeavor to prove the practicality of the design features.

Sun-cured plastic laminated bandages were applied

to one of the engineers to simulate a long forearm stump bi­ lateral amputee.

Independent elbow flexure was permitted,

with forearm supination and pronation, but wrist motion was restricted.

The fingers were formed into a solid block

permitting only knuckle movement and the thumb was elongated to provide a suitable contact or gripping surface in opposition to the second and third fingers.

It was found

that with this immobilization, normal social functions could be performed with ease.

The same experiment was applied to

a hand on two other men with similar satisfactory functional results.

It was thus proved that the palmar type finger grip

in conjunction with a fixed thumb was feasible, and the hands were so constructed. It was in this design that the three-jaw chuck type of grip was perfected, and finger pads of a relatively flat nature increased the effectiveness of the grip.

The operating

mechanism was removable and could be made up and tested as a bench assembly. Prom a design standpoint, the problems were cut in half as were the number of parts required, but a more complex

67 tooling problem resulted, since the type of laminate required from a stress standpoint was best fabricated in steel molds and arbors.

As a result, the tooling required for the

preparation of the prototype hand was in the nature of pro­ duction tooling. Three hands of this design were made and partially tested.

While the termination of the project prevented a

complete evaluation of this design, it was felt that it accomplished the objectives for which it was designed.

It

also proved the feasibility of using hitherto untried mater­ ials to reduce the weight and the possibility of reducing the moment of inertia of the hand about the supination and pronation axis by shifting the distribution of the weight toward the wrist and toward the center of the axis. Force multipliers♦

20

A force multiplier is an

auxiliary mechanism which may be applied to a machanical power transmission system to increase an input force and decrease its linear travel by means of a simple lever action, this lever action taking place only when the input force has reached or exceeded a predetermined value.

The need for a

force multiplier in artificial hand design for the cineplastic operation arose from the fact that the power obtainable from a large proportion of muscle tunnels is at best marginal. 20 A. A. Marks, Manual of Artificial Limbs (New York: Marks Company, 1920), p. 179.

68 When these muscle tunnels are connected to a hand mechanism through a linkage, regardless of whether or not the linkage transmits directly the force-distance characteristics of the muscle tunnel, the average effective fingertip force is inadequate.

By the addition of a force multiplier in the

actuating system, it was found that muscle power can be con­ centrated to develop adequate fingertip forces where gripping strength is needed, regardless of the position of the hand opening. After studying various mechanisms and methods of pro­ ducing force multiplication, a latch and brake type of mechanism was selected as being most easily adapted to the purpose. passes.

It is essentially two pulleys over which a cable The pulleys are mounted on a lever that pivots at

a fixed place in the arm.

In the non-multiplying position,

the lever is locked in a fixed position by a latch, and the pulleys are free running.

When the tension in the cable

attached to the muscle motor exceeds a predetermined value, the force in the pre-load spring is exceeded.

This trips

the latch holding the lever fixed and at the same time a brake mounted to the lever fixes one of the pulleys solidly to the lever.

This prevents the cable from running through

the mechanism and turns the mechanism into a simple lever. The pulling cable from the muscle motor is attached to the lever at a point further from the fulcrum pivot than is the

69 cable to the hand.

This produces a simple lever force multi­

plication with the corresponding reduction in the travel of the increased p u l l . ^ Three models of the force multiplier were made, each of which contained some improvement and reduction in size, so that the third model was of a size that could be installed in a prosthesis.

The cable used originally as the tension

medium was changed to chain to provide longer life and because the chain would stay in the pulley grooves when not under tension.

The third model was also made with a clutch rather

than the original latch in an effort to eliminate the very perceptible jerk in the whole mechanical system when the latch was released by the tension of the muscle tunnel when the pull reached a predetermined force* Chain.

After a thorough investigation into the

possibilities of cables and thin steel bands, it was decided that a small chain was definitely needed for the force multiplier.

The final samples sent to the University of

California Prosthetic Laboratory at Berkeley for test were made from a bar of SAE 4130 steel, and were "bicycle type” mechanical load-carrying chain with ultimate tensile strength of two hundred fifty pounds* 21 The Development of Improved Mechanical Hands, Arm and Auxiliary Devices for Amputees who Have Had the Cineplastic Operation* Sierra Engineering Company, Sierra Madre, California, June 30, 1947.

On February 10, 11, and 12, 1947, the Hand and Arm Symposium conducted at Northrop Aircraft, Inc., requested that Sierra design and construct a revised chain as well as the necessary tools and fixtures therefor.

22

The chain

designed was characterized by a multiple link or laminated link construction, the links being stamped from sheet stock and assembled on shouldered pins with the outside links riveted in place against the shoulder so that a close fit between link groups was obtained but freedom of rotation of the inside links was assured.

Two chain sizes were fabricated

one for one hundred fifty pounds tensile strength and the other three hundred pounds.

The same links were used for

both chains but the stronger had a greater number of link laminations and a longer shoulder pin. were made for final evaluations

Two types of chain

one of stainless steel links

and SAE 4130 pins, the other with beryllium copper links and SAE 4130 pins.

The chain is capable of operating over a 5/16

inch diameter pulley and provides a working load of approxi­ mately one hundred pounds for the one hundred fifty pound chain and two hundred pounds for the three hundred pound chain.

^ Sierra Engineering Company of Sierra Madre, California, held a tier contract with Northrop*s Hawthorne Project. This allowed the Northrop Department to work on basic ideas in design and farm out to smaller plants related parts for an appliance.

71 Sense of touch mechanism.

Some experimental work was

done with a view to developing a sense of touch mechanism that could impart a feel of contact at sensitized areas on an artificial hand.

An analysis of the problem indicated

possibilities in either electric or hydraulic systems. The hydraulic system was developed sufficiently enough to determine the essentials required for such a system,

A

unit was tried consisting of two bladders or diaphragms connected by a rubber tube, one in the finger and one against the skin of the natural arm.

Experiments indicated that an

incompressible fluid in a non-expanding system should be used to make such a system as sensitive as possible.

No further

work was done on this system. Electrical methods were also investigated but the use of direct current electrical impulses was ruled out because the resistance between an electrode and the skin was subject to wide variations due to temperature, humidity, body per­ spiration, etc., and when the impulse was sufficient to be felt, a sensation of pain was generally produced. not considered practical.

This was

Therefore a design was formulated

using subsonic vibrations between 60 and 100 cycles.

The

mechanism consisted of a simple electric switch element, a direct current buzzer or vibrator element, and a small light­ weight battery.

The experimental switch consisted of two

flat spring strips of suitable size and shape to be placed on

72 a fingertip pad or other location in the hand.

The first

light pressure of the hand touching an object at the region of the switch would press the flat spring contacts together, thereby closing the electric circuit.

The buzzer element

was located at a convenient place in the prosthesis and held in place in such a manner as to provide light but consistent contact with the natural arm skin.

Hearing aid wires and

batteries were sued to complete the system.

Lack of time

prevented service testing of this unit. Cosmetic gloves.

While the problem of making cosmetic

gloves was not included in the Sierra Engineering Company contract, suitable gloves were not available to fit the hands designed under the project and it was therefore found necessary to do some work along these lines. Milton Tenenbaum of New York City, and Mellon Institute were asked to provide sample gloves but none were available at the time.

American Anode, Inc., of Akron, Ohio, however,

were able to make up samples of plain flesh colored latex base gloves from male plasters that were sent to them.

The

.020 inch thick gloves made from these plasters were satis­ factory; they had a reasonable appearance and were not expensive in production quantities. By this time, various groups were working on cosmetic gloves with the markings and coloration of the natural hand.

73 In April, Major M. Fletcher of the Army Prosthetics Research Laboratory, Army Medical Center, Washington, D.C. provided Sierra with a sample polyvinyl glove post-formed to fit the 3B hand.

The use of the cosmetic glove, of course, had a

very definite affect upon the design of the hand, and two general patterns were established; 1.

A skeletal hand with padding or lightweight fillers to produce a suitable hand shape.

A

cosmetic or other type of glove is mandatory for the proper functioning and use of such a hand. 2.

A crustacia or shell hand with padding or grips added in local areas, all faired in together to produce a suitable hand shape.

A cosmetic or

other type glove is optional with this hand. Since the gloves developed so far were still likely to tear and to be victim of accident, it was decided to direct the work at Sierra along the lines of the second general pattern.

Then, if a cosmetic glove met with an

accident, the hand would still be usable until another glove could be obtained. The arm by Sierra Engineering Company.

When the

development work on arms was discontinued at Vard, Inc., it was taken over by Sierra Engineering Company.

The Vard arm

23

23 Vard, Inc., Subcontractor^ Final Report, The Development of Artificial Arms for Amputees who have had the Cineplastic operation, July 15, 1946 - February 28, 1947.

•HUa

75 was analyzed from a construction standpoint and results seemed to indicate that the bearings and supinatlng mechanism were too heavy and did not work well in this application* The supinatlng mechanism was found to have excessive friction which was traceable to both the type of gearing chosen and to the routing and type of supination cables*

Another cause

of this friction was found to be in the bearings.

The arm

was tested on an amputee and it was decided that the only satisfactory method of improving the operation was to do a complete job of modification*

The results of this experi­

mentation and revision of the Vard arm brought the following conclusions: 1.

A satisfactory method of supination control could

be obtained through the application of bevel gears which operate through elbow flexure, with provisions added for engaging and disengaging these gears and locking the wrist in desired positions*

The lock could be operated directly

from a harness pull* 2*

For prosthesis operated by cineplastic muscle

tunnels, a more practical method of hand control would be gained through a design based on a reciprocating member mounted in the center axis of the arm assembly*

To this, an

equalizing member could be attached which would receive the cables extending from the muscle pins*

Having all operating

controls located in the center axis of the arm would eliminate

76 rotation of the cables and/or controls on the outer surface of the arm structure, 3.

The weight element must be a deciding factor in

the design of all structure and mechanism, and ease of assembly and repair must not be overlooked# Testing#

A hand testing mechanism was built on which

a hand was opened and closed repeatedly with a loading at the tip of the fingers and thumb of approximately two pounds# Hand 3B was placed in this fixture with a two-pound fingertip pressure when the hand was closed and a one-and-one-fourthpound fingertip pressure when the hand was open#

The hand

was cycled at 175 cycles per minute, with a visual inspection every hour for failures or mal-performance of any kind#

At

35,000 cycles, the hand motion ceased due to the jamming of loose screws in the palm pivot bracket#

The hand was cleaned,

oiled, re-assembled and replaced on the cycle test fixture where it continued to a total of 64,050 cycles. The pilot hand of the 4A design was tested with a maximum spring loading on each of the four fingers of one and three fourths pounds and a minimum loading of one pound at a cycling frequency of 192 cycles per minute#

At 115,900

cycles, the hand mechanism had stiffened slightly but upon cleaning and oiling regained its initial freedom and smooth­ ness of movement.

At 271,250 cycles, the pistol grip holder

77 mechanism failed and was repaired.

At 274,100 cycles, the

third finger had broken loose at the defective bond of the knuckle bar, and the knuckle bar had failed between the third and fourth fingers on the dorsal side, through a region of the bar known to be defective, but the hand operating mechanism was still in good condition with no detectable loosening up of the bearings or finger movement. Later, the 3B hand was reinstalled in the testing equipment and an additional 3,140,300 cycles were obtained, after which the test was stopped since 3,000,000 cycles were considered a reasonable measure of satisfactory service life. The loosening to be expected from normal wear resulted but the wear was of such small magnitude that the h a n d fs mechanism was considered still suitable for further service use. Another 4A hand was cycled with a spring loading at each of the four fingers of one and three fourths pounds when the hand was opened.

The hand was cycled to 1,269,450

cycles at a frequency of 190 cycles per minute.

At this

point a bearing boss came loose permitting a twisting motion in the knuckle bar which resulted in the failure of the operating mechanism.

However, it was considered that a few

simple changes in the method of attaching the plastic bearing boss would eliminate this failure and it was felt the 4A design could pass the 3,000,000 cycle life test.

78 The importance of the structural design of the 4A hand lies in its ruggedness and lightness, both of which are directly attributable to the use of the glass-cloth laminate in a stressed-skin structure. structural purpose.

Every molded piece serves a

The weight of the finished hand is

nine and one fourth ounces, much less than that of any previous hand. Conclusions.

The study and experiment involved in

the development of the aforementioned prosthesis indicated that the design of an improved prosthesis requires the combi­ nation of functional usefulness, natural or cosmetic appearance, light weight, and ready response to precise movement control, and long trouble-free service life.

To

attain these ends requires the coordination of several factors: 1.

The functional and cosmetic values must be care­ fully balanced.

2.

A prosthesis must be made from materials with a high strength-to-weight ratio.

3.

A long service life must be attained in a pros­ thesis for it to be satisfactory from the amputee1s viewpoint.

4.

The price of a prosthesis must be within the means of all amputees.

79 III.

ARTIFICIAL EANDS PROJECT DEVELOPED BY VARD, INCORPORATED

On February 5, 1947, a second tier subcontract was negotiated between Vard, Inc., and Northrop Aircraft, Inc., under the latter1s subcontract with the Committee on Artificial Limbs.

The objective of this contract was the

design and development of a new above-wrist prosthesis for use by amputees who have had the cineplastic operation.

It

was proposed that Vard, Inc., should cooperate with Sierra Engineering Company of Sierra Madre, California, who were working on the development of an artificial hand for use with the Vard arm. A definite pattern was laid out for the guidance of this project.

The first step of this pattern was a period

of education.

All persons connected with the project were

required to acquire a knowledge of anatomy and the complex motions of which the natural arm is capable. Second, a system of classification of amputees was devised based on length of stump, availability of muscles for the cineplastic operation and functions to be provided by the prosthesis. The third step was to make a general analysis of the problem.

To do this, a determination was made of the needs

of each class of amputee according to the physical members

80 required (hand, wrist, forearm, etc.).

Then a general

solution of the problem was attained by determining the power sources required to operate the various members and the power sources available from the cineplastic musclemotors and harness.

From this analysis, an assignment of

power sources to functions could be made. It was then possible to proceed with the actual con­ struction of a specific prosthesis for a specific amputee, based upon the analysis of the problem and the general solution for each class of amputees. In addition to the work performed toward the primary objective, the development of an improved control system was investigated rather thoroughly. Throughout the preliminary analysis, it was kept in mind that power sources for the hand should always be inde­ pendent of other functions and should preferably be provided by the cineplastic muscle-motors•

This would give the amputee

full control of the hand or hook, regardless of the position or motion of the arm or shoulder, thus shortening his training period and improving his dexterity. A brief study was made of the various motions of which the natural arm and hand are capable.

Since it was recognized

that it would not be reasonable to provide all of these motions in a prosthesis, the most important were considered necessary and assigned individual power sources, the less

2 1 1 9 2 - 0 6 7 NORTHROP ARM 0 SOCKET; WRIST DISARTICU­ LATED, ASSEMBLED & CUT-AWAY VIEW.

PROJ. 17

82 important were assigned individual power sources if practical or given passive motion, and the least important were eliminated. An analysis of the problem and discussions with Sierra Engineering Company indicated that only one or two power sources could be provided to the hand.

If one power source

was used, it was felt it should be used to close the hand and a spring used for opening.

If two could be provided,

one should be used for closing and the other for opening. Controls for the hand were kept independent of other functions and were provided by the muscle-motors. Wrist flexure was found to be important but since it was determined that active control of wrist flexure is not required at all times, passive flexure, in which the degree of flexure can be pre-set and locked by the amputee, was considered satisfactory. Abduction and adduction of the wrist was not considered of sufficient importance to warrant additional complexity of the prosthesis. Rotation of the hand and wrist about the longitudinal axis at the forearm was considered highly desirable and should be provided in all prosthesis.

Whether or not it

should be under the positive, active control of the amputee seemed to depend upon the number of additional complications required in the prosthesis and control system to provide

s e x