THE HISTORY OF THE IDEAS ONTHE FUNCTION OF THE BICEPS

BRACHII MUSCLE AS A SUPINATOR

by

J. G. BEARNINTRODUCTION

Before Leonardo da Vinci the movement of supination was always given asa function of the muscle now called the brachio-radialis. Leonardo, in a seriesof annotated drawings made between 1505 and I5IO, made it abundantlyclear he understood that the biceps brachii was the principal supinator, inaddition to its action as a flexor of the elbow. However, because he was neithera teacher of anatomy, nor did he publish his notebooks, this observationremained unnoticed, and it was not until 200 years later that this action was re-discovered by Cheselden and recorded in the first edition ofhis textbook in 17I3.Seven years later in I720 Winslow read a paper to the Academie Royale desSciences also describing this action of the biceps as if it were his own discoveryand included it in the first edition of his textbook in 1732, giving a very cleardescription of the movement. This supinating action of the biceps, althoughbriefly noted in most textbooks published after 1732 was not re-examined indetail until Duchenne's classic account in the Physiology of Motion published inI867, to which little has been added to this day.

Galen (c. A.D. I29-201)The traditional method of studying muscle action, as described by Galen in

De Usu Partium, was the examination of dissections accompanied by pullingon the dissected muscle, and confirmed by the palpation of the muscle bellyand tendon in the living subject during active movement of the joint. Galen'sfirst and most comprehensive treatise on anatomy, De Usu Partium, was com-pleted by A.D. I 75. His second, De Anatomicis Administrationibus, was completedin A.D. 177, and has recently been translated by the late Dr. Charles Singer. Itis essentially a practical book, probably based on a shorthand record of a seriesof public lectures given on anatomy in Rome when he became Physician to theEmperor in A.D. 176. In these two books Galen deals with the muscles ofsupination and pronation and gives a good account of their anatomy andattachments. He also describes the two anterior muscles which flex the elbow(i.e. the biceps and the brachialis). However, as Vesalius (I543) points out, hecontradicts himself in his two books. In De Usu Partium he describes how thebiceps is not only a flexor but also bends the forearm outwards while thebrachialis flexes and bends the arm inwards. In De Anatomicis Administrationibus,he states the opposite view, that the biceps flexes the elbow bending the armslightly inwards while the brachialis flexes, bending the arm slightly outwards.

32

The Histoty of the Ideas on the Function of the Biceps Brachii Muscle as a Supinator

He then goes on to say that 'if both muscles perform their function correctlythe bend of the articulation is inclined neither to right nor left', but no mentionis made of supination as a function of the biceps.

In De Anatomicis Administrationibus the brachio-radialis muscle is described,and Galen says that by it, 'this part is turned inwards', Singer interprets thisas flexion of the elbow. The pronator teres, pronator quadratus and supinatormuscles are all described and their functions correctly given. A second supinatormuscle is described, Singer's translation reads: 'The yet longer and morefleshy muscle which lies altogether above this [i.e. the supinator] also movesthe hand into the supine position. . . .' Singer suggests that this refers to theextensor carpi radialis longus and brevis, although it seems probable that Galenis here referring to the brachio-radialis.

Galen thus had a very clear idea of the muscles concerned with flexion of theelbow, and with supination and pronation, except that he did not recognizethe supinating function of the biceps. He also believed that straight flexion oftheelbow could only be produced by the combined action of both the biceps andthe brachialis muscles acting together. This point was finally corrected byVesalius (I543), who showed that either muscle could produce straight flexion.

Galen's works, like so many other ancient writings, were kept alive by Arabictranslations, and were then rendered into Latin between the eleventh andfourteenth centuries. Avicenna (980-1037) briefly epitomizes Galen's accountof the muscles, condensing them into a few pages. Mundinus (c. 1270-I326)carries this condensation to almost complete omission, and describes only themuscles ofthe anterior abdominal wall and the thorax. The muscles ofthe limbsare ignored completely, the Public Anatomies at this time being concerned onlywith the contents of the abdomen, thorax and head. Berengario da Carpi(c. 146o-I530) may be considered as a link between the medieval anatomy ofMundinus and the modern period of anatomy ushered in by Vesalius in I543.His commentary on Mundinus was published in I 521, and his short introductionto anatomy (Isagogae breves) a year later, two years after Leonardo's death.However, Berengario's treatment of the limbs, apart from a plate illustratingthe superficial veins and muscles shows little advance from the teaching ofMundinus and contains no account of the individual muscles.

Leonardo da Vinci (I452-I5I9)The annotated drawings made by Leonardo da Vinci make it abundantly

clear that he understood not only the supinating action of the biceps, but alsothat the brachio-radialis can act as a flexor of the elbow. Leonardo da Vinci'sachievements as an anatomist have been discussed many times, and it is onlynecessary to say that of all his anatomical drawings, those of the muscles are thefinest and the most accurate. They were produced between I505 and 1510mainly during his second Milanese period, when he had obtained a copy ofDe Usu Partium. The anatomical studies made during this phase were largelyon osteology and myology, and are much superior to the drawings of earlierperiods. It was during this time in Milan that he met Professor Marcantonio

33

J. G. Bearn

della Torre, who died ofplague in 15I I. In his notes Leonardo describes plansfor the production ofa Treatise on Anatomy, and this has given rise to the traditionstarted by Vasari but without foundation, that he was to collaborate with Torrein this project. It was during this period too that Leonardo had some facilitiesfor dissecting the human body.

Anatomists are indebted to Dr. Charles D. O'Malley and Dr. J. B. de C. M.Saunders for publishing the anatomical drawings of Leonardo da Vinci,together with a translation ofhis notes, which fill all the available spaces betweenthe pictures. The account of Leonardo's views on the biceps and supination aretaken from this translation. Before describing them, it must be emphasized thatthe schism between anatomy and physiology did not occur until the nineteenthcentury, up to then the study of structure and function was one, and allanatomists had a teleological approach to the structures they dissected. Manyof Leonardo's drawings are intended to illustrate the function of the part asmuch as its anatomy. This is well illustrated in the drawings in which themuscles are replaced by cords, so that their function and also their relationshipto each other may be better understood.The biceps muscle and its function as a supinator is shown in no less than

three plates, one of which has five separate drawings on it. They were drawnbetween 1505 and I5I3, three being dated about 15I0. An earlier plate (Plate I),dated about I504 shows six drawings ofthe front ofthe arm, and a study ofthesemakes it clear that he had not yet appreciated the function of the biceps. Thefirst drawing shows the brachialis correctly. The second shows the biceps musclesuperimposed on the brachialis, but the tendon of biceps crosses deep to thebrachialis muscle, and the radius and ulna appear to be transposed. The thirdsketch has more muscles added and is even more confusing.

However, by the beginning of his second Milanese period in 1505 Leonardohas understood this action. On a plate (3) in which a number of embryologicaldrawings were added years later, he shows two drawings of the bones of theupper limb with the brachialis, biceps and pronator teres muscles drawn todemonstrate their functions.The plate is headed 'On all the forces and action of the forearm, that is to

say which muscle rotates, which flexes it.' He goes on to say,the muscle (biceps) serves to rotate the bone (radius) through half a revolution ... and thesecond muscle (brachialis) is made to bend the arm into any degree of angle. It is attached tothe humerus and to the non-revolving bone (ulna) of the arm. It is very strong because it has tosupport a very large weight. It cannot rotate the arm like the muscle (biceps) and the muscle(pronator teres) in opposite motion like the cords of a trephine, an instrument for drilling.These two muscles (Biceps and pronator teres) are arranged by their Author that they may

Plate i-Drawings of upper limb muscles by Leonardo (c. 1504) (QV 5r). Thisplate shows that Leonardo has not yet understood the supinating action of thebiceps. ist drawing shows the brachialis muscle. 2nd drawing shows the biceps andis full of errors. The biceps tendon passes deep to the brachialis. The remainingdrawings are even more confusing.Plate 2-Two sketches of the elbow region with the biceps, brachialis, triceps andpronator teres muscles added, by Leonardo (c. 1510-I!2) (QV 7v). These twosketches distinguish between the action of the brachialis as a pure flexor, and thebiceps as supinator.

34

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The History of the Ideas on the Function of the Biceps Brachii Muscle as a Supinatorturn the hand to the front and to the back without having to rotate the elbow of the arm. Thetwo muscles are wrapped round the bone (radius) in opposite directions, of which when onepulls and unwraps itself, the other wraps itself around the bone like the ropes which revolvea trephine.

Later, probably with the biceps muscle in mind he writes:that such a rotatory action is especially important in picking up food turning the hand andputting the food in the mouth.

This describes very beautifully the combination of both supination and flexion,performed by the biceps.

This plate in particular, but also others (2, 5), indicates that Leonardounderstood the function of the biceps, brachialis and pronator teres muscles. Ofthe other muscles concerned with these movements, one drawing (4) shows thathe understood the brachio-radialis muscle to be a flexor of the elbow. The deepmuscles of the forearm receive scant attention. The supinator is not shown inany drawing, although the pronator quadratus muscle is hinted at in outlinein one plate (5).To Leonardo da Vinci then, must go the credit for discovering and recording

the supinating action of the biceps brachii. The function was certainly notunderstood by Galen, nor by any of the medieval anatomists writing beforeLeonardo.Leonardo died in France in I 5 I 9, and fourteen years later Vesalius published

his Fabrica, in I543. It is difficult to understand why this function of the bicepsremained unknown to Vesalius, and was not to be described again for 200 years.Although Leonardo did not teach anatomy and never published his notebooks,the oral tradition was strong at this time and he was close friends with at leastone anatomist, della Torre, and many of the leading men of art and science ofEurope.

Vesalius (i5i4-64)Vesalius, in both editions of his Fabrica, I543 and I555, discusses the action

of the biceps and brachialis muscle.He quotes Galen as saying that one flexes and moves the forearm inwards so

that the hand touches the inner side of the shoulder, and that the other flexesand moves the forearm outwards and the hand touches the outer side of theshoulder. Vesalius points out that Galen contradicted himself in his two books,De Usu Partium and De Anatomicis Administrationibus. Vesalius reinvestigates thisproblem and finds that each muscle produces straight flexion, however he failsto notice the supinating action of the biceps. The brachio-radialis is describedPlate 3-Two sketches of the upper limb, with the biceps, brachialis and pronatorteres muscles added, by Leonardo (c. I505) (QIi I 9v). This plate is headed, 'Onall the forces and action of the muscles of the forearm, that is to say which musclerotates it, which flexes it.' These two sketches demonstrate beautifully the supinat-ing function of the biceps (see p. 34). The embryological drawings were madebetween I5IO and I512.Plate 4-A drawing of the flexor muscles of the arm, by Leonardo (c. 1513)(Qi I I gr). This drawing shows beautifully the action ofthe brachio-radialis muscleas a flexor of the elbow.

35

J. G. Bearn

as a supinator, and the structure and function of the supinator and the prona-tors are correctly given.

Vesalius's Fabrica was by no means the only anatomical work published inthe first half of the sixteenth century.

Berengario da Carpi published a commentary on Mundinus in I 521 and hisown short introduction to anatomy, Isagogae Breves in I522. He followed themedieval tradition and ignored any details of the limb muscles. Dryander(I537) and Canano (1540?) both published illustrated books prior to Vesalius.That of Canano is worthy of comment.Canano was made Professor of Anatomy at Ferrara in 154I, when aged

twenty-six, and immediately began to issue in parts an illustrated text ofanatomy. The first fasciculus was published from Ferrara and is undated, butseems to have been issued in I541 or at the beginning of I542. It consists oftwenty-seven plates accompanied by a brief text, each plate showing onemuscle in detail, superimposed on the skeleton. The muscles are shown ingreater detail and with greater accuracy than in the Fabrica of Vesalius. Thebook was never completed and even the first volume was suppressed by Cananohimself, after Vesalius had visited him in November of I 542 and shown him theproofs of his Fabrica.

Estienne, although his book was started in 1536, was delayed by law suitsuntil 1545, the year of publication. Eustachius's famous plates, prepared at thesame time were not published until I7I4, and the text has never been found.Massa published his book without illustrations in 1536. An examination of theplates and texts of all these anatomists make it clear that none understood thesupinating function of the biceps muscle. It is interesting to look at one ofEustachius's plates in detail. In plate 35, the upper limb is shown with theforearm in partial supination. Two muscles are present, the brachio-radialis andthe biceps. These two muscles are accurately represented and one may speculateas to whether this was meant to demonstrate the point that the biceps could beconsidered as a supinator. But as the text is lost, this point cannot be decided.However, such a new idea would certainly have become known to otheranatomists had Eustachius understood and taught this function for the biceps,and yet on this point all his contemporaries remain silent, repeating the teachingof Vesalius that the biceps is a straight flexor.The followers of Vesalius, Columbus (I559) and Fallopius (I56 i), both

followed Vesalius in their accounts of the biceps muscle, although in otherrespects making important contributions to anatomy.Towards the end of the sixteenth century, and in the seventeenth century,

many textbooks of anatomy were published. At least fifty-nine books in Englishappeared between I548, when Vicary produced his plagiarism of Lanfranc andde Mondeville, and 1700 (Russell, 1949). Many ofthese were by British writers,some being translations ofbooks from other countries. Some of the better knownones include Bauhin (i6o5), Casserius (I627), Spieghel (I627), Vesling (I653),Bartholin (i656), Gibson (I682) who attached the biceps to the ulna,Blancardus (i688), Diemerbroeck (I689) and Keill (I698).

36

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Plate 5-This plate shows five drawings of the upper limb bones, with thebiceps and pronator teres muscles added, by Leonardo (c. I5IO) (FA Iv). Thepronator quadratus muscle is hinted at in the third sketch. The last drawing

shows well the action of pronator teres.

P--

The Histoty of the Ideas on the Function of the Biceps Brachii Muscle as a SupinatorThree books on the muscles were produced byJohn Browne (I68I and I705)

who used plates slightly altered from Casserius (I627); by Cowper (I694 andI698), who used Bidloo's plates published in I685-in the second edition of1724 Cowper refers with scorn to Browne's book as 'most erroneous'; and byJames Douglas who published in 1707 a small book on the muscles of man andthe quadriped.

These many texts have been examined and all follow the traditional view thatthe biceps is a flexor and the brachio-radialis is a supinator.

Cheselden (1688-1752)The first anatomist who gives any hint that he understands that the biceps is

also a supinator and the brachio-radialis is a flexor is Cheselden, who publishedhis textbook in I713, when only twenty-five years of age. In this he says onpage 6o that the biceps 'bends the cubit and turns it supine'. Later, on page 66,he says ofthe brachio-radialis muscle, 'this contributes very much to the bendingof the cubit, the hand being turned supine'. He goes on to say that the flexorsassist the pronators and the extensors assist the supinators.Thus Cheselden is the first anatomist to record the supinating action of the

biceps, and the flexing action of brachio-radialis.William Cheselden was born in I 688, and in I703, when only fifteen, became

a pupil of William Cowper, and soon after was apprenticed to Mr. Ferne,Surgeon to St. Thomas's Hospital. His progress as an anatomist was rapid. ByI7 I he was running his own course ofanatomy, consisting of thirty-five lecturesfour times a year, and continued to give these for twenty years, first at his ownhouse and later at St. Thomas's Hospital. He published his first syllabus forthese in I711.

His textbook, which was to become perhaps the most popular one of its timewas published in 1713 and ran into many editions, the thirteenth and lastpublished in I792 in London. Cheselden was taught anatomy by Cowper, whopublished in I694 the Myotomia Reformata in London, and in I698 The Anatomyof Humane Bodies, at Oxford, using Bidloo's plates. Cowper died in 1709, andCheselden in the preface to his book published in I7I3, makes no reference tohis teacher, Cowper, but pays tribute to James Douglas,that most accurate and indefatigable anatomist whose assistance has been very useful to me inthe compiling of this book, and who so obliged the world with an exacter description of themuscles than any extant.

This refers to Douglas's small book on the muscles published in 1707, which ismuch inferior to Cowper's books. Neither Cowper nor Douglas describe thebiceps as a supinator and we can assume that this was an original discovery ofCheselden.

Winslow (I669-1760)Although Cheselden must be given the credit for the first description of the

biceps as a supinator in 17I3, Winslow gives a far more detailed and accurateaccount of the movement.

37

J. G. BearnJacques-Benigne Winslow was born in I669 in Denmark, of Swedish origin,

and was destined for the Church like his father, first studying theology, butdecided to take up medicine, and eventually entered the Faculte in Paris in1702. He gave the courses in anatomy at the Jardin du Roi, in the place ofDuvernay, and later in his own house for many years, and eventually becamethe Professor of Physick, Anatomy and Surgery in I743 which he remaineduntil his death at ninety-one in I 760.Winslow published his own textbook in Paris in I732, and an English

translation by George Douglas, M.D., F.R.S., brother ofJames andJohn Douglas,appeared in 1733.

In the preface Winslow observes that

Several years ago I was informed, that if I did not publish myself, what I had said and demon-strated in my courses of anatomy, especially those given in my own house, where I often talkwithout the least reserve, I should have the mortification to find that some other person woulddo it for me.

He goes on to comment on

the sincerity of that Gentleman who translated Dr. James Douglas's English myography intoLatin, in declaring in his notes that I am the author ofseveral things which I had only mentionedby word of mouth.

This refers to a Latin translation made by Joannes Frederius Schrieber, aPrussian from Konigsberg who worked at Leyden under Albino and Boerhaave.It was published in 1729 at Leyden and under the biceps muscle is the footnote'also supinates the radius and indeed with greater force than its supinatores.Winslow understood this Paris. 1720'. It is interesting to note that a secondedition ofJames Douglas's book was published in 1750 in Edinburgh but nomention of supination as a function of the biceps is found.The footnote refers to a paper read by Winslow in I720 to the Academie

Royale des Sciences in Paris on I5 May.One other anatomist refers to Winslow's observation before the publi-

cation of his textbook. This is Lorenz Heister, Professor at Altdorf, who quotesWinslow's paper of 1720 in the second edition of his textbook, CompendiumAnatomicum, published in 1732.

Winslow's paper of 1720 is entitled 'De l'Action des Muscles en General, etde L'usage de plusieurs en particulier'. One small paragraph towards the enddeals with the biceps, saying that he has found that the biceps is a strongersupinator than the ordinary supinators (i.e. brachio-radialis and supinator), andthat it acts principally when the elbow is flexed. He refers to this as a newobservation of his own.

In the first edition of his textbook (I732) Winslow deals with this in moredetail, the English translation (I733) by George Douglas reads,The biceps by its insertion in the radius performs likewise the motion of supination and thatwith much more force than the muscles commonly assigned for that action by the name ofsupinatores.

38

The History of the Ideas on the Function of the Biceps Brachii Muscle as a Supinator

Later, on the uses of the muscles he enlarges on this point.

The biceps which I likewise name the coraco-radialis ... moves the forearm in two differentmanners; that is it bends both bones, and turns the radius upon the ulna; performing bothmotions by its insertion in the Radius alone.

It is surprising that George Douglas, the translator of Winslow's book, whomust have known Cheselden's book, was content to translate Winslow's state-ment that the biceps is also a supinator 'as I have already shown' without makingany comment on the earlier statement by Cheselden. However another brother,John, had quarrelled with Cheselden, and wrote an extraordinary and pettycriticism of Cheselden's book on osteology, so this may be a clue to GeorgeDouglas's silence on this point.Winslow also describes the brachio-radialis as a flexor of the elbow, saying 'it

is more fitted for this motion than for supination'. He gives credit to Heister forthis observation, referring to the Compendium Anatomicum, published in I 717 andtranslated into English in 172i. Heister in a footnote states, of the brachio-radialis 'May also serve to bend the cubitus'. Heister most probably obtainedthis information from Cheselden's book of 1713, to which Heister refers in hispreface.

Winslow, although familiar to all students for the foramen, deserves to bebetter known particularly on account of his studies on the physiology of move-ment. He is perhaps the first anatomist to discuss groups of muscles performingmovements rather than the traditional view of describing the action producedby the contraction of an individual muscle. One example will illustrate thispoint. It has only recently been emphasized that the supra-spinatus muscle isnot merely an abductor of the shoulder, but serves to hold the head of thehumerus into the glenoid cavity to prevent upward displacement during con-traction ofthe deltoid. This point is discussed with great clarity by Winslow whoeven makes the point that the supra-spinatus forms a fulcrum and so enables thedeltoid to abduct the arm.Under the movements of pronation and supination Winslow is also the first

to observe that as the lower end of the radius moves round the ulna, this bonemoves in the opposite direction.Winslow was well ahead of his time in his account of muscle action and it is

not until I867 that Duchenne in his classical book on the physiology of move-ment, continues this work and ushers in the modern era ofthis field offunctionalanatomy.

Duchenne (I86-75)Guillaume Benjamin Amand Duchenne was born in September i8o6 in

Boulogne, France; his father was a captain in the French Navy, operating inthe English Channel during the times of Napoleon I. He received his earlyeducation in a religious school, where he acquired a knowledge of the classicallanguages and an inclination towards natural science. In I825 he entered theMedical School of Paris, graduated in I83I with a thesis on burns.

39

J. G. Bearn

After graduating, he returned to Boulogne to begin medical practice; he waskind and conscientious and was liked by his patients. In I835 he becameinterested in the application of faradic current in the treatment of disease. Atthe time it was applied by means of platinum needles inserted into tissues, apainful procedure which often produced necrosis. Duchenne found that theapplication ofelectrodes to the skin was enough, and soon realized the possibilitiesof this method in both diagnosis and treatment.He began an investigation of the muscular response to electrical stimulation

and in I842 migrated to Paris to get better facilities for his research.His most important book, Physiology of Motion appeared in I867, and was

based on both his clinical observations as well as his experimental electricalstimulation.He died in 1875 and is rightly regarded as one of the greatest clinicians of a

brilliant period of French neurology. He deserves credit for the discovery oflocomotor ataxia, progressive muscular paralysis and glossopharyngeal paralysis.Moreover, in I855, Duchenne located the lesion of poliomyelitis in the anteriorhorn of the spinal cord.

His book, Physiology of Motion, must be considered amongst the greatestworks on muscle action. He investigated with very few exceptions the entiremuscular system correlating his experimental findings with his immense clinicalexperience of paralysis and deformity. He used not only normal subjects butalso fresh cadavers which had still retained the ability to respond to electricalstimulation. He supplemented his research by numerous experiments on animalsand by careful anatomical dissections. His approach to the problem is entirelyteleological, and he sees a divine purpose in the minutest functional interpreta-tion of every muscle. This perhaps reflects his early religious training.Modern views on flexion of the elbow joint and the movements of pronation

and supination at the radio-ulnarjoints stem from the experiments he performed,the electrical stimulation of the muscles and detailed observation of themovements.The following is an account of his findings taken from Kaplan's translation

of his book (I 949).Brachialis. Faradization of the brachialis produces powerful flexion of the forearm withoutaffecting pronation of the radius on the ulna, in other words permitting independent pronationand supination.

Flexion is produced directly without lateral deviation.Biceps. (Flexor supinator.) With the hand in pronation, the electrical stimulation of the bicepsproduces immediate supination and simultaneous flexion of the forearm. If while the biceps isthus in contraction by a strong current, an attempt is made to produce pronation, there isstrong resistance to this attempt.Brachio-radialis. Electrical stimulation produces powerful flexion of the forearm. Simultaneouslyit places and maintains the hand between pronation and supination. However the pronationproduced is less extensive than the supination produced by the biceps.Supinator. Stimulation produces powerful and complete supination, independent of all othermovements.Pronator teres. Pronator quadratus. Electrical stimulation produces powerful pronation. Pronatorteres also flexes the forearm, either if pronation is complete or resisted, but with little force.

40

The Histoty of the Ideas on the Function of the Biceps Brachii Muscle as a SupinatorHe goes on to say that previously only two muscles were considered to

produce flexion, i.e. biceps, brachialis, and that it is surprising that anatomistshad not found earlier that the brachio-radialis muscle is a powerful flexor ofthe forearm, especially as the muscle is visible during flexion against resistance,especially if the hand is in pronation.He then goes on to say that it was considered previously that only two muscles

pronated and two muscles supinated the forearm. His electrical stimulationshave confirmed the action of three, pronator teres, pronator quadrater, andsupinator, but in the case of the brachio-radialis, the main action was flexionof the elbow, and to place the forearm midway between pronation andsupination, and that the biceps is a powerful supinator. This is summarized bysaying that the brachialis is an independent flexor, the biceps is the flexorsupinator and brachio-radialis is the flexor pronator, and that the remainingthree muscles, the supinator, the pronator teres and the pronator quadratus areindependently supinator and pronators.

There is little in this account with which the modern anatomist or physiologistwould disagree, except perhaps the name 'flexor pronator' for brachio-radialis,but even here, Duchenne recognizes that the muscle brings the forearm into themid-position between pronation and supination. Duchenne mentions thatWinslow described the biceps as a powerful supinator, and also gives him creditfor describing the brachio-radialis as a flexor of the elbow.

It is now an accepted part of anatomical teaching that during pronation andsupination some movement of the ulna takes place. Duchenne makes this pointclearly and gives credit to both Winslow and to Vicq d'Azyr for earlier accountsdemonstrating that the movement of the radius is accompanied by oppositemovement of the ulna.One final question remains unanswered. Could either Cheselden or Winslow

have had access to Leonardo da Vinci's drawings? Exactly when the anatomicaldrawings became a part of the Royal Collection is not known, but certainly byI690 they were in Kensington Palace, when Queen Mary showed them toConstantign Huygens. It is William Hunter who seems to be the first anatomistto study them, and he speaks of them with enthusiasm and announces hisintention to publish them. This was prevented by his death in 1783 and thefirst selection of anatomical drawings to appear was not until 1796, by JohnChamberlaine, in his Imitations of Original Designs by Leonardo da Vinci.

ACKNO WLEDGMENTSThe author is indebted to the late Dr. Charles Singer for advice in the preparation of this

paper, and to Dr. F. N. L. Poynter and the Staff of the Weilcome Historical Medical Libraryfor their unfailing help, and to Dr. Charles O'Malley for permission to quote from his translationof Leonardo da Vinci's text.

4I

J. G. Beam

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Trans. G. Douglas, M.D.

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