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 HXdo0 11819 f^ : ^^*-^^ Lm>^^^l^' ..^c^^^cMi Y .^ 
 
 The Significance of Muscular Variations, 
 
 Illustrated by Reversions of the 
 
 Anti-Brachial Flexor Group. 
 
 By GEO. S. HUNTINGTON. 
 
 [Trans. N. Y. Acad. Sci., Vol. XIV. (Aug. 28, 1S95) 231-259.] 
 
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 http://www.archive.org/details/significanceofmuOOhunt 
 

 THE SIGNIFICANCE OF MUSCULAR VARIATIONS, 
 
 ILLUSTRATED BY. REVERSIONS OF THE 
 
 ANTI-BRACHIAL FLEXOR GROUP. 
 
 By Geo. S. Huntington. 
 
 Read by Title, Feb. 11, 1895. 
 
 The study of muscular variations, if carried on systematically, 
 embracing observations made on a large number of subjects, 
 cannot fail to reveal certain finer differentious, which, while lost 
 in a mere enumerative record of muscle variations, gain a new 
 and important significance when grouped together and com- 
 pared in an eflfort to trace the morphological meaning of the 
 variant condition. This becomes most strikingly apparent in 
 the case of certain appendicular muscles, and especially of some 
 muscles of the fore-limb. The extreme modifications which, in 
 vertebrates possessing an anterior extremity, widely diflferent 
 functional requirements have impressed on this portion of the 
 locomotoiy apparatus, may properly be held responsible for the 
 fact that here variations of the most composite t^^pe are to be 
 encountered. A glance at the divergent forms presented by the 
 vertebrate pectoral girdle will convince us that the muscular 
 structures connected with the same must offer deviations from 
 the primitive types, which not onlj^ change the arrangement of 
 homologous muscles in different forms, but which will afford 
 the opportunity for numerous reversions to the original con- 
 dition in the case of any individual muscle. 
 
 The specialization of the fore-limb, in exchanging a purely or 
 chiefly locomotory function for one which includes or substitutes 
 the prehensile function, and the consequent higher development 
 of the manus, has more especially served to single out the anti- 
 brachial flexor group, and to add to the function of flexing the 
 forearm at the elbow-joint the more complicated movements of 
 radial rotation in supination of the hand. In some instances 
 this additional functional requirement has sufficed to specialize 
 certain members of the flexor group as supinators, modifying 
 the insertion so as to restrict the same chiefly or entirely to the 
 radius, and separating a portion of the flexor mass by complete 
 cleavage from adjoining muscular strata. 
 
 This is most excellently seen in the so-called Biceps flexor 
 cubiti of Man and Primates generally, a muscle which acts as 
 
PVlU" /'Jt 
 
 •23"2 TRANSACTIONS OF THE [MAY 13, 
 
 one of the chief radial supinators, while its flexor function is to 
 a considerable extent subordinated to this main action. 
 
 In muscles of this type variations are frequently encoun- 
 tered, many of them being reversional in character and pointing 
 to previ.Q.ns ancestral types of myotectiire. 
 
 The definition, which certain muscular attachments obtain by 
 specialization of function, is accompanied by the concomitant 
 reduction or elimination of other connections which have lost 
 their original value and significance in the new sphere of the 
 muscle, or would even, if retained, interfere with the same. 
 
 The muscle, in returning in an incomplete form to these ob- 
 solete conditions, presents reversions to which many of the ob- 
 served variations may properly be ascribed. 
 
 No muscle presents these features more strongl}' developed 
 than the Biceps flexor cubiti. The muscle is, next to the Pal- 
 maris longus, the most variable in the body, Macalister* in 
 his Catalogue of Muscular Anomalies enumerating no less than 
 45 separate variations. 
 
 It is our purpose in the present paper to discuss only a cer- 
 tain group of these variations, and to endeavor to obtain an in- 
 sight into their significance. 
 
 The human material, on which the following observations 
 have been made, consists of 464 upper extremities dissected 
 during the year 1893 to 1894 in the Anatomical Laboratory of 
 Columbia College. 
 
 As the explanation of the probable derivation and significance 
 of certain of these variations of the Biceps muscle is closely con- 
 nected with the morphology of the remaining antibrachial flexor 
 group, it will be desirable to take a general view of the ar- 
 rangement of this group, before proceeding to the details. 
 
 In the lowest vertebrates a continuous and non-segmented 
 plane of muscular fibres proceeds from the ventral aspect of the 
 trunk to the flexor surface of the anterior limb. This condition 
 is best represented b}- the muscular apparatus of the pectoral fin 
 in fishes. 
 
 In ascending the scale differentiation leads to the more or less 
 complete separation of this muscular mass into layers and strata, 
 which may or ma}- not preserve connections with each other, in- 
 dicative of their original union. 
 
 A consideration of the general arrangement of the flexors of the 
 forearm in higher vertebrates reveals the existence of three main 
 divisions or laj-ers,^ more or less blended with each other. 
 
 ♦Alexander Maealister. Additional Observations on Muscular Anomalies in Human 
 Anatomy (III. Series), with a Catalogue of the Principal Muscular Variations hitherto 
 published. Transact, of the Royal Irish Academy, Vol. XXV., Pt. I., Dublin, 1872. 
 
 t G. M. Humphry, Obser\-ations in Myology, Cambridge and London, 1872, p. 163. 
 
1895.] NEW YORK ACADEMY OP SCIENCES. 233- 
 
 1. Superficial layer, a portion of the superficial ventro-ap- 
 pendieular muscular sheet, reaching, usually by combination 
 with the succeeding layer, a skeletal or fascial insertion in the 
 forearm. Usuall}^ but few and unimportant traces of this la3' er 
 are found in higher forms, the great bulk of the superficial fibres 
 passing from the trunk to the anterior extremity terminating, as 
 Pectoralis Maj or and Latissimus dorsi, respectively on the radial 
 and ulnar margin of the humerus. Occasionally, however, the 
 Pectoralis Major is not arrested at the radial tubercle of the 
 humerus, but, as in Orycteropus, accompanies the Biceps to the 
 radius, or, as in the Otter and Wildcat, together with some 
 fibres of the Trapezio-Deltoid, accompanies the Brachialis anticus 
 to the ulna, or, as in the Seal, expands into the fascia of the fore- 
 arm and thus reaches the hand.* 
 
 2. Intermediate layer, constituting the " extrinsic " limb 
 muscles of Humphry, derived from the deeper portion of the 
 ventro-appendicular sheet, forming muscles arising from the 
 pectoral girdle and passing over the elbow to the bones of the 
 forearm. This group is represented by the Biceps, which 
 muscle, besides its relation to the Coraco-humerals, presently to 
 be considered, presents various degrees of continuity with, and 
 separation from, the following layer. 
 
 3. Deep layer, formed by the "intrinsic " limb muscles, aris- 
 ing from the humerus, and pursuing the same course as the 2nd 
 layer, represented by the Brachialis anticus, or in some in- 
 stances (Hippopatamus) by the Brachio-radialisf , which mus- 
 cle in this animal is larger and occupies the space on the outer 
 side of the humerus from which the Brachialis anticus usually 
 arises. 
 
 Here we meet with a replacement of the usual Brachio-ulnar 
 by a Brachio-radial flexor, to the complete exclusion of the 
 former. 
 
 The 2d and 3d laj^ers, i. e., Biceps and Brachialis anticus, 
 either considered by themselves, or more especially when viewed 
 in the light of their mutual relation, present many points of 
 morphological interest, and suggest explanations of human re- 
 visional variations of the former muscle. 
 
 A general review of the conditions found in the anti-brachial 
 flexor graup will call for the consideration of the following 
 points : 
 
 I. Morphology of the Bicep)S, the variations of the muscle and 
 their significance. 
 
 * Humphry, op. cit., p. 147. 
 t Humphry, op. cit., p. 163. 
 
234 TRANvSACTIONS OF THE [MAY 13, 
 
 II. Relations of Biceps to the adjoining deep ventro-ap)pendic- 
 vlar muscles, viz.: the Goraco-humerals. 
 
 Ill Relations of Biceps to the deep intrinsic flexor of the 
 forearm, viz.: the Brachialus anticus. 
 
 I. Morphology of the Biceps Flexor Cubiti. 
 
 We may in the first place consider the composition of the 
 human Biceps in the light derived from the comparative study 
 of the muscle in other vertebrates. 
 
 Although our knowledge of comparative myolog\' is still 
 somewhat meagre, considering the extent of the subject, and al- 
 though the results of investigations appear at times too frag- 
 mentary and uncertain, yet enough is known to justify us in 
 regarding the form in which the Biceps usually presents itself in 
 man as the result of certain specializations of function acquired 
 by the upper extremity, which have brought about a greater de- 
 finition of certain portions, whereas other parts, lacking the 
 stimulus of this functional requirement, have retrograded and 
 have become to a great extent rudimentar}- or entirelj' elimin- 
 ated. 
 
 A. Origin. 
 
 In the complete form the Biceps occupies two points of origin 
 from the shoulder-girdle corresponding to the anterior edge of 
 the glenoid socket and to the coracoid element. 
 
 The actual arrangement of the muscle in individual forms 
 will be naturally greatly influenced by the structure of the 
 girdle, and notably by the predominance or reduction of the 
 coracoid and its appendages. An instance of this is afforded 
 b}' the extensive Coraco-radial muscle which represents the 
 Biceps in Cryptobranchus japonicus, whereas, in man}' other 
 forms, the coracoid origin of the muscle is much reduced or ab- 
 sent, and the Biceps appears as arising solel}' from the glenoid 
 margin. 
 
 A glance at the arrangement in the vertebrate series will im- 
 mediately indicate that the origin of the muscle is confined, 
 strictly speaking, to the coracoid element of the pectoral girdle. 
 It ma}^ arise hy a single head, or, as in man, the origin may be 
 double, hence the name. 
 
 If, as in us, the coracoid is reduced and the scapula corre- 
 spondingly increased, the muscle, if it preserves its double origin, 
 will arise b}- one head from the small coracoid process, by the 
 other from that portion of the glenoid margin which is con- 
 tributed by the coracoid bone. If the long tendon of the glenoid 
 head of our Biceps is examined in subjects between the ages of 
 
1895.] NEW YOKE ACADEMY OP SCIENCES. 235 
 
 ten and puberty, it will be found in every instance connected 
 with the so-called sub-coracoid centre of ossification. 
 
 Hence our division of the muscle into glenoid or scapular, and 
 coracoid heads, while convenient as corresponding to adult con- 
 ditions, should not cause the fact to be forgotten that the 
 Biceps is entirely a coracoid muscle in in its origin. We might, 
 considering the probable significance of our coracoid ossification, 
 speak of the coracoid or long and precoracoid or short head of 
 the muscle. The origin of the Biceps taking place in this man- 
 ner from a single skeletal element, it is not surprising to find 
 the consolidation of the two heads, which are present in man 
 and the primates generally, to be of very frequent occurrence in 
 lower forms. It will then depend upon the prominence of the 
 coracoid element, and the relation of the origin to the glenoid 
 socket, whether this single head will be denominated as the 
 coracoid or glenoid muscle. 
 
 B. Insertion. 
 
 In like manner we find a considerable range in variation in the 
 insertion of the muscle. It may be attached to either or both 
 bones of the forearm, according to the functional character of 
 the limb, and the specialization of rotatory radial movements of 
 the forearm and hand. Moreover, in forms presenting the origin 
 by two heads from the pectoral girdle, either or both of the 
 girdle heads may be connected with either, or, hy division of the 
 insertion, with both of the forearm bones. 
 
 Consequently the analysis of the Biceps muscle would result 
 as follows, retaining the names " glenoid " and " coracoid " as 
 designating respectively the outer and inner girdle origins of 
 the muscle : 
 
 Complete type form of muscle, four heads. 
 
 1. Gleno-radial. 3. Goraco-radial. 
 
 2. Gleno-ulnar. 4- Coraco-ulnar. 
 
 This type becomes inodified in various forms by reduction 
 and elimination of two or more heads, so as to present a number 
 of variations. Krause* first pointed out this quadricipital 
 character of the human Biceps, based on careful dissection of 
 the muscle and analj^sis of the fibres at the insertion. He also 
 collected a number of comparative anatomical facts in support of 
 this view of the compound character of the muscle. A by no 
 means exhaustive consideration of the structure of the Biceps in 
 the lower animals reveals the existence of the following reduc- 
 
 * W. Krause, Specielle und Macroscopische Anatomie, Hanover, 1879, p. 223. 
 
236 TRANSACTIONS OF THE [maY, 13, 
 
 tions ami combinations of the four type lieads of origin and 
 their insertion. 
 
 I. Gleno-radial alone. 
 
 A typical instance is pi-esented by Talpa europea. Geohe- 
 gan * describes the muscle in this animal as follows : The Bi- 
 ceps is single-headed, arising just above the glenoid articular 
 surface by a long tendon which passes through a groove in the 
 extreme anterior end of the humerus ; this groove is at first a 
 tunnel. It is onl}- after it has passed the elbow that the muscle 
 becomes fleshy. Insertion below the middle of the radius. 
 Welcker f corrects this statement to read that the insertion is 
 above the middle of the radius. 
 
 Other forms presenting the Glenro-radial muscle are : Nj'Cti- 
 pitheeus, Stenops, Horse, Ruminants, | Lutra vulgaris. § 
 
 II. Goraco-radial alone. 
 
 This form of the Biceps muscle is presented by Orycteropus 
 capensis, Rhinoceros, Frog, Toad, Lacerta, || Phoca vitulina.^ 
 
 In this animal the muscle arises from the coracoid process, 
 is inserted into the radial tuberosity, and is combined with a 
 short head, which is connected with the Brachialis anticus. 
 
 III. Gleno-ulnai- alone. 
 
 The muscle occurs in this form in H^'rax capensis and in Ro- 
 dents generally.** 
 
 lY. Coraeo-ulnar alone. 
 
 Humphry .fl in describing the muscular s^-stem of Crypto- 
 branchus japonicus gives the following account of the Coraco- 
 brachialis longus. 
 
 " This is the largest muscle arising from the coracoid. It 
 arises from the hinder edge of the coracoid and divides into two 
 portions. Of these the larger and inner or lower division is in- 
 serted into the ulnar edge of the humerus for a quarter of an 
 inch above the internal condj'le ; the other division, being nearly 
 
 *Geohegan, Myology of the Fore-limb of Talpa europea, Proceedings Dublin 
 Biolog. Assoc, Vol. I., 1875, p. 5. 
 
 t Welcker, H., Archiv f. Anatomic und Entwicklungsgeschichte, 1878, p. 23. 
 
 X Krause, op. cit., p. 22?i. 
 
 'i Lucae, J. C. G., Die Robbe und Otter (Phoca vitulina und Lutra vulgaris) in ihrem 
 Knochen und Muskelskelet, Frankfurt a/ j,_ 1873, p. 204. 
 
 I Krause, op. cit., p. 223. 
 
 \ Lucae, op. cit., p. 199. 
 
 ** Krause, op. cit., p. 223. W. Krause, Anatomic des Kaninchens, p. 107. 
 
 tt Op. Cit., p. 33. 
 
1895.] NEW YORK ACADEMY OE SCIENCES. 237 
 
 as large, is partl}^ inserted into the side of the long tendon of 
 the Biceps, while a bundle of its fibres is continvied on over the 
 elbow, and is inserted into the ulna near the joint. The last de- 
 scribed division must represent the short or coracoid origin of 
 the Biceps in man. There is no trace of it in Menobranch, 
 Axolotl or Newt. The muscle in them, though large, is confined 
 to the humerus in its insertion." 
 
 The Coraco-radialis or Biceps arises from the external sur- 
 face of the coracoid, between the Epicoraco-brachial (Pectoralis 
 minor) and the short Coraco-brachial, as a fan shaped muscle, the 
 fibres of which pass across the short Coraco-brachial and soon 
 converge into a long tendon, which runs down beneath the Pec- 
 toral. Having passed the Pectoral it receives the fibres of the 
 long Coraco-brachial, passes over the elbow joint, and is inserted 
 into the palmar surface of the upper end of the radius close to 
 the joint. It is supplied by the nerve which perforates the scap- 
 ula and which supplies also the superficial Coraco-brachial. 
 
 Y. Gleno-radial and Coraco-radial. 
 
 Meckel * describes the double-headed Biceps of Ornithorrhyn- 
 chus paradoxurus, one head arising from the anterior, the other 
 from the posterior coracoid, the muscle passing to be inserted 
 into the radius. 
 
 YI. Gleno-radial and Gleno-idnar . 
 
 Dog. 
 
 Origin : By a single strong tendon from the edge of the glen- 
 oid fossa, the tendon passing through the capsular ligament of 
 the joint. 
 
 Insertion: By a strong tendon chiefly- into the ulna, although 
 attached also to the radius by a smaller slip. 
 
 Other forms presenting the same arrangement of the muscle : 
 
 Choloepus didact^-lus.f 
 
 Two-toed sloth. 
 
 Origin: ^y a long and strong tendon from the glenoid border of . 
 the scapula, passing down through the intertubercular groove 
 in the capsule of the shoulder. The muscle descends on the 
 arm, dividing into two strongly develoijed bellies, one passing 
 with the Pectoralis and Deltoid to the tuberosity of the radius, 
 the other with the Brachialis anticus to the coracoid process of 
 the ulna. 
 
 * System der Vergleichenden Anatomie, p. 516. 
 
 tLucae, J. C. G., Der Fuchsafie und das Faulthier (Lemur macaco and Choloepus 
 didactylus) in ihrem Knochen-und Muskelskelet, Frankfurt ^j m, 1882. 
 
238 TRANSACTIONS OF THE [MAY. 13, 
 
 The combination of glono-raxlial and gleno-uluar muscle is also 
 noted in the Pig and Cat. 
 
 YII. Gleno-radial and Goraco-ulnar. 
 
 Uromastix spinipes.* 
 
 Origin: by two distinct portions from coracoid, one tendin- 
 ons from proximal part, the other muscular more laterally from 
 anterior part, corresponding with the coracoid and glenoid 
 origins in man. 
 
 Insertion: After being joined by Brachialis anticus, which 
 is large, arising from the lower part of the humerus, the con- 
 joined tendon is inserted into the radius and ulna. 
 
 VIII. Coraco-radial and Gleno-ulnar. 
 
 In Marsupials, in which the two muscles are entirely separate 
 from each other.f 
 
 IX. Coraco-Radial and Coraco-Ulnar. 
 
 This arrangement of the muscle is found in Em3'S and Cha- 
 meleon. | 
 
 A general consideration of the facts above adduced leads to 
 the natural conclusion that the Biceps muscle of the fore-limb, or 
 its homologue, presents throughout the vertebrate series evi- 
 dences in its structure and. arrangement of a general type-plan 
 of construction, modified in the ditferent groups by the functional 
 requirements of the Jimb, and in all probability' b}' the varying 
 relations assumed by the tendon of origin to the capsule and 
 the cavity of the humero-scapular articulation. I believe that 
 this fundamental type-construction of the appendicular muscular 
 SA'stem is the element to which we must refer for the explanation 
 of deviations from the arrangement normally found in any- one 
 species. Partial returns to the potential t3'pe-form constitute 
 reversions of far broader significance than those usually grouped 
 under the head of atavism. 
 
 In respect to the human subject, as well as in the case of the 
 remaining vertebrates, and especially mammalia, our exact 
 knowledge regarding the lines of descent of present orders and 
 sub-orders is still so rudimentary and imperfect, that the im- 
 propriet}' of referring nearly all muscular variations to atavism 
 and direct inheritance becomes at once apparent. The fact that 
 
 ♦Humphry, op. cit., p. 64. 
 tKrause, op. cit., p. 223. 
 JKrause, op. cit., p. 223. 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 239 
 
 in ease of any given human muscular variation, a muscle of 
 similar character is found in one of the lower vertebrates does 
 not warrant the assumption that both are derived by inheritance 
 from an immediately precedent common ancestral form. The 
 form in which the variant human muscle appears normally may 
 be incalculably far removed from man, may even belong to a dif- 
 ferent vertebrate class. That the structural coincidence of the 
 two muscles is to be taken as indicating anything more than the 
 most generalized relationship of vertebrates is difficult to be- 
 lieve. For many of the aberrant muscular conditions observed 
 in man a very comprehensive view as to their derivation must be 
 a,dopted. I believe that we are right in referring such varia- 
 tions, as will be considered in detail below, to the development 
 of an inherent constructive type, abnormal for the species in ques- 
 tion, but revealing its morphological significance and value by 
 appeai'ing as the normal condition in other vertebrates. 
 
 The question, as far as it affects the variations to be considered, 
 may be represented graphically somewhat in the following man- 
 ner : 
 
 X y X y 
 
 Fig. 1. Type form of Muscle. FiG. 2. Cleavage variation. 
 
 In Fig. 1 let the line a-b represent the skeletal origin, the 
 line x-y the corresponding insertion of a muscular plane. 
 Oonsidering this arrangement as the type, in which the entire 
 space between origin and insertion is occupied by an uninter- 
 rupted muscular plane, it will become apparent that modifica- 
 tions of this type can take place in two ways, 
 
 1. Cleavage variations, retaining in general the original scope 
 of origin and insertion, in which the original muscular plane ap- 
 pears as two or more distinct muscles. (Fig. 2.) 
 
 2. Reduction variations, where a portion of the origin or of 
 
240 
 
 TRANSACTIONS OF THE 
 
 h 
 
 [may 13, 
 
 Fig. 3. Keductioii vari.ition; Origin 
 retained; Insertion reduced. 
 
 Fig. 4. Eeduction variation; Origin 
 retained ; Insertion reduced. 
 
 Fig. 5. Reduction variation; Oiigin 
 and Insertion reduced; Points re- 
 tained. 
 
 Fig. 6. Reduction variation; Origin 
 and Insertion reduced; Points ex- 
 changed. 
 
 h 
 
 Fig. 7. Reduction variation; Origin 
 and Insertion rediiced; Points re- 
 tained. 
 
 Fig. 8. Reduction variation; Origin 
 and Insertion reduced ; Points ex- 
 changed. 
 
1895.] NEW YORK ACADEMY OF SCIENCES 
 
 h 
 
 241 
 
 Fig. 9. Eeduction variation; Origin 
 reduced. ; Insertion retained. 
 
 Fig. 10. Eeduction variation; Origin 
 reduced; Insertion reta,ined. 
 
 the insertion, or of both, is eliminated, necessitating, under 
 some conditions, a change in the direction of the muscular fibres. 
 
 These variations are represented schematically by Figs. 3-10, 
 it being of course evident that the arbitrarily selected points a 
 and &, and x and y. may be placed anywhere along the lines of 
 origin and insertion respectively. 
 
 In defining the following variations in the human Biceps I pre- 
 fer to accentuate this relation to a fundamental vertebrate type- 
 plan, and, at the expense of introducing an additional term into 
 the complex reversional nomenclature, I will speak of them as 
 " Myo-typical Reversions.'''' 
 
 In man the Biceps is composed of the Gleno-radial and Coraco- 
 radial divisions, combined with a superficial ulnar fasciculus, 
 possessing a fascial insertion along the ulnar border of the fore- 
 arm by means of the semilunar fascia. 
 
 We may group the variations which concern us here with 
 reference to the derivation and destination of the accessory 
 portions, representing additional glenoid and coracoid heads, 
 which have lost their distal ulnar attachment. 
 
 I. Gleno-ulnar Head. 
 Appears in the following forms : 
 
 1. Capsulo-pectoeal tendon. 
 Diagnosis : Tendinous fibres in the form of scattered bundles, 
 or more compactly arranged as distinct tendon-bands, arising in 
 conjunction with the capsular ligament from the glenoid margin of 
 the scapula, differentiating from the capsule at the upper border of 
 the intertubercular groove and extending downwards over the 
 
 Transactions N. Y. Acad. Sci., Vol. XIV., Sig. 16, August 28, 1895. 
 
242 TRANSACTIONS OF THE [mAY 13, 
 
 long gleno-radial head, rooting in the bicipital canal and merg- 
 ing with the deep surface of the tendon of the Pectoralis major, 
 or, in some instances, extending beyond the pectoral tendon to 
 the deep fascia of the arm. 
 
 This is the most common form in which the variation presents 
 itself. 
 
 Cases : 
 
 1. 9, white, U. S., aet. 62. January 30, 1894. 
 Plate XVII. Right upper extremity: 
 
 A distinct tendon, imbedded in the capsule of the joint, over- 
 h'ing the intertubercular groove, covering the long bicipital 
 tendon and passing to the deep surftice of the Pectoralis major 
 tendon, on which it spreads out in the upper third, terminating 
 b}- interlacing with the pectoral tendon fibres. 
 
 Left upper extremity : 
 
 Presents the same slip, more strongly developed, extending 
 nearly to the lower border of the Pectoralis major tendon. 
 
 Plate XVIII. Capsule between the tuberosities partly divided, 
 to show the deep position of the tendon imbedded in the shoulder 
 capsule, and indicating a tendenc}' toward intra-articular immi- 
 gration. 
 
 Plate XIX. The same joint opened from behind, with head of 
 humerus removed. The thickened strand on the inner surface of 
 the anterior wall of the capsule, just in'front of the long Biceps 
 tendon, is directlv continuous with the fibres of the tendon slip. 
 
 2. S \ Austria, \aet. 05. October 11, 1893. 
 Plate XX. Right upper extremity. 
 
 Strong fibrous band arising from capsule over lesser tuber- 
 osity, and descending over long tendon of Biceps, connected 
 with deep surface of 'Pectoralis major tendon, to the lower mar- 
 gin of which it extends. 
 
 A tendon band from anterior part of capsule passes to outer mar- 
 _gin of short head, indicating tendency to subdivision of this head. 
 
 3. 9. Germany, aet. 84. '' November 9, 1893. 
 ■Plate XXI. Right upper extremity. 
 
 Well marked strong fibrous fasciculus, extending from cap- 
 sule of shoulder joint over the bicipital groove and contents to 
 the deep surface of the Pectoralis major tendon. Some fibres 
 merge with the pectoral tendon, while others continue below its 
 inferior margin to join the deep fascia of the arm. 
 
 The left upper extremity of the same subject presents a 
 transition to the form next to be described (Gleno-uluar muscle). 
 A strong tendinous band, incorporated at its origin in the cap- 
 sule of the shoulder joint, passes downward, covering in the bi- 
 cipital groove and attaching itself to the upper margin and deep 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 243 
 
 surface of the Pectoralis major tendon. In part continuous 
 with this tendon band, in part arising independently from the 
 deep surface of Pectoralis tendon, four muscular slips arise, the 
 two upper passing backward, the two lower downward, to in- 
 corporate themselves with the substance of the Biceps muscle. 
 The bundles are all distinctly muscular in character. 
 
 The following additional instances, in which the aboA'e de- 
 scribed band was present, were noted in the series : 
 
 4. ^, U. S. white, aet. 38. December 27, 1893. 
 
 Small glenoid tendon slip joining deep surface of Pectoralis 
 major tendon over the bicipital groove. Present on both sides. 
 
 5. 9 Ireland, aet. 72. January 9, 1894. 
 Slip present on both sides. 
 
 6. $ Ireland, aet. 40. December 21, 1893. 
 Right upper extremity. 
 
 Large tendon band, arising from capsule external to long 
 head of Biceps, inserted on deep surface of Pectoralis major 
 tendon. 
 
 7. $ Ireland, aet. 32. November 28, 1893. 
 Right side. 
 
 8. S Germany, aet. 54. 
 
 Large band on left side. Insertion confined to Pectoralis 
 major tendon. 
 
 9. $ Germany, aet. 52. December 14, 1893. 
 Right side. 
 
 Very large tendon \ inch wide, passing from glenoid margin 
 interwoven with the capsule, to the united bellies of Biceps, with 
 intermediate attachment to the deep surface of Pectoralis major 
 tendon. 
 
 10. $ Ireland, aet. 40. 
 Both extremities. 
 
 Strong tendon from glenoid edge to deep surface of Pectoralis 
 major tendon. 
 
 11. $ Italy, aet. 50. 
 Right side. 
 
 Very broad tendon slip, in part continued beyond Pectoralis 
 tendon into the Biceps. 
 
 12. 9 ,,IJ. S., negro, aet. 24. 
 Left side : 
 
 Glenoid tendon to junction of heads of Biceps. 
 
 2. Gleno-Dlnar Muscle. 
 
 Occurs in three forms or variations : 
 
 (a.) Origin identical loith that of the Capsulo-pectoral tendon, 
 passing downward and presenting a more or less close connection 
 
244 TRANSACTIONS (»F THE [MAV 13, 
 
 xcith the deep surface of the Pectoralis major tendon. Becoming 
 muscular a short distance beyond the loiver border of the Pec- 
 toralis tendon the slip passes obliquely inivards across the long 
 head, fusing with its anterior surface and inner margin, or 
 joining the outer margin of the shoi't coracoid head. 
 
 Cfl.SGS '. 
 
 1. i, U. S., white, aet. 24. November 29, 1893. 
 Plate XXII. Right side. 
 
 A strong shining tendinous band arises from the glenoid 
 margin incorporated with the shoulder capsule. Passing down 
 and emerging from beneath the edge of the coraco-acromial 
 ligament, the tendon becomes closely connected with the deep 
 surface of the Pectoralis major tendon, interlacing with its fibres 
 at right angles, iN'ing upon the long tendon of the Biceps and 
 forming the main portion of the roof of the inter-tubercular 
 groove. Toward the lower portion of the pectoral tendon the 
 inner half of the slip gradually separates itself from the same 
 and forms a small muscular belly which joins the outer margin 
 of the short biciptal head near its junction with the long head. 
 The outer portion of the tendon slip gradually passes deeper 
 into the substance of the Pectoralis tendon, with which it is in- 
 tricately interlaced. On the bottom of the inter-tubercular 
 groove are several well marked longitudional tendinous bands, 
 connected below with the tendon of the Pectoralis major ; above 
 they in part separate from the tendon, passing upward and in- 
 ward and crossing at right angles the tendon fibres of Latissimus 
 dorsi and Teres major; in part they go upward and outward, 1\'- 
 iug in the floor of the bicipital groove under cover of the long 
 Biceps tendon. 
 
 A small third internal humeral head of the Biceps is present 
 in the same arm, derived from the Coraco-brachialis insertion. 
 
 2. ^ , U. S.. white, aet. 50. 
 
 Plate XXIII. Right upper extremit}-. 
 
 Tendon slip with intermediate attachment to deep surface of 
 Pectoralis major tendon, arising in connection with capsular 
 ligament from the glenoid margin, and passing to the inner bor- 
 der of the long bicipital head, at the line of junction with the 
 short head. 
 
 3. .?, Ireland, aet. 32. November 29, 1893. 
 
 Plate XXTIII. Left upper extremity of subject, whose right 
 upper extremity- presents the variation described under " b 2," 
 Plate XXYII. vidi ibid. 
 
 4. $ , U. S., negro, aet. 50. December 14, 1893. 
 Plate XXIY. Right side. 
 
 Tendon in part fused with deep surface of Pectoralis major 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 245 
 
 tendon at the lower border of which a short muscular belly de- 
 velops which joins the Biceps. 
 
 Between the long and short bicipital heads an additional ten- 
 don slip arises from the capsule, near the base of the coracoid 
 process, and, passing down on the outer side of the short Biceps 
 tendon, receives some upper fibres of insertion of a short Coraco- 
 brachialis superior, and then joins the outer margin of the short 
 Biceps head just before the latter meets the long head. 
 
 The left side of the same subject presents an instance of the 
 next succeeding form. 
 
 5. <? , Germany, aet. 52. December 14, 1893. 
 
 Yery large accessory glenoid head, ^" broad, passing to the 
 united bellies of the Biceps. Upper tendinous portion very 
 distinct and adherent to Pectoralis tendon. 
 
 6. $, TJ. S. white, aet. 23. January 30, 1894. 
 Plate XXY. Left upper. 
 
 Gleno-ulnar tendon connected but loosely with deep surface 
 of Pectoralis major; leaves tendon of Pectoral as a distinct 
 band at about the middle of its posterior surface and a short 
 distance below the distal margin of the pectoral tendon, ex- 
 pands into a superficial broad and flat muscular belly, which 
 descends upon the long bicipital head, lying in close connection 
 with the outer margin of the coracoid head from which it is 
 completely separable to a point midway between the lower 
 border of the Teres major and Latissimus dorsi and the elbow. 
 The fibres of this accessory head then join the coracoid head 
 along its external border. About 3 cm. above the internal 
 condyle the long head joins the tendon of insertion, developed 
 on the deep and external aspect of the combined coracoid and 
 accessor}^ heads. 
 
 The bicipital fascia receives some superficial and oblique 
 fibres (decussating) from the outer and anterior aspect of the 
 radial tendon. 
 
 The right arm of the same subject presents a Gleno-epitroch- 
 lear slip {vide infra). 
 
 (6.) Tendon of origin of Gleno-ulnar muscle is comi:)letely 
 free from Pectoralis major tendon, under cover of which it lies. 
 
 Cases : - 
 
 1. ^, r. S., negro, aet. 50. December 14, 1893. 
 
 Plate XXVI. Left upper extremity of subject whose right 
 extremity is described under " a 4," Plate XXIV. 
 
 Long, distinct glenoid tendon, overlying long bicipital ten- 
 don, under cover of Pectoralis major, but not connected with 
 the same. Becomes muscular opposite lower third of pectoral 
 tendon and crosses over long bicipital head to join its inner 
 margin at about the middle of the arm. 
 
246 TRANSACTIONS OF THE [mAY 13, 
 
 2. <?, Ireland, aet. 32. November 29, 1893. 
 
 Plate XXYII. Rii^ht upper extremity. Under cover of in- 
 sertion of Peetoi-nlis major, a broad tendinous band descends 
 over the intertubercular groove, derived from the shoulder cap- 
 sule and covering the long tendon of the Biceps, to which it is 
 connected by a thin but strong tendinous lamina. The lower 
 portion of this band terminates in a broad muscular sheet, which 
 turns inwards to join the medial margin of the long head. 
 
 A few scattered- tendinous fibres descend oblifpiely from the 
 capsule to the outer margin and anterior surftxce of the lesser 
 head. 
 
 The left upper extremity of the same subject presents the 
 gleno-ulnar slip with intermediate connection to the deep pec- 
 toral tendon. (Variety "a.") Plate XXYIII. 
 
 Here a strong tendinous band, arising from the intertubucular 
 portion of the capsule, and connected with the upper part of the^ 
 deep surfiice of the Pectoralis tendon, becoming free below,' 
 crosses obliquel_v over the long bicipital tendon to fuse with the 
 inner margin of its muscular belly a short distance before the 
 same is joined by the coracoid head. 
 
 A small tendinous bundle (Capsulo-intermediate fibres), aris- 
 ing from the coracoid portion of the capsule, accedes to the outer 
 pare of the coracoid head. 
 
 Insertion of Biceps in this arm: Radial tendon derived as 
 usual from the deep surface of the combined muscle. Superfi- 
 ciall}- some fibres pass from the outer part of the muscle across 
 the radial tendon into the semilunar fascia, which is inserted by 
 a forked process into the radial as well as the ulnar side of the 
 deep forearm fascia. 
 
 c. Transition forms between "a" and "6," and variations. 
 
 Cases : 
 
 1. S , Ireland, aet. 53. March 16, 1894. 
 Plate XXIX. Left upper extremity. 
 
 Gleno-ulnar tendon slip, presenting a reduplication of the 
 origin. The outer band is connected with the Pectoralis major 
 tendon ; the inner is free. They join opposite the middle of the 
 pectoral tendon and develop a ?tout, muscular bell}', which can 
 be followed as far as the elbow, where a few of the deeper fibres 
 pass into the inner margin of the radial tendon of insertion, 
 whereas the remainder of the xleep and all the superficial fibres 
 of the accessory head, joined b}- some from the outer margin of 
 the main muscle, pass inward into the bicipital fascia. 
 
 2. S, Ireland, aet. 35. March 14, 1894. 
 Plate XXX. Left upper extremity. 
 
 Gleno-ulnar tendon, double at origin, a portion passing into 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 247 
 
 the pectoral tendon, the remainder into the outer margin of the 
 short bicipital head and into the Coraco-brachialis, which muscle 
 is strongly developed in its upper part. 
 
 3. $, German}--, aet. 64. October 14, 1893. 
 
 Plate XXXI. Right upper extremity. 
 
 Double glenoid tendon, the outer division giving otT a branch 
 to join the deep surface of the pectoral tendon. The tendons of 
 origin then unite and form a muscular belly which passes down 
 and in over the long bicipital head to join the deep surface and 
 outer margin of the short head. 
 
 3. Gleno-epitrochlear Tendon. 
 
 Diagnosis: Origin as Capsulo-pectoral fibres from glenoid 
 margin with capsule of shoulder. Connected with deep surface 
 of Pectoralis major tendon at the lower border of which the 
 fibi'es are gathered into a long, slender tendon which passes 
 obliquely down and in, across the Biceps, brachial vessels and 
 large nerves, to be inserted into the anterior part of the internal 
 epicondyle. 
 
 The structure exhibited by this variation in its upper portion 
 is such as to admit of no doubt of its identity with the fibres 
 described above as Capsulo-pectoral and Gleno-ulnar with inter- 
 mediate pectoral connection. 
 
 The lower long tendon with its epicondylar implantation rep- 
 resents, I believe, a rudimentary Gleno-ulnar muscle, whose in- 
 sertion has been shifted to the internal epicondyle. The latter 
 is a point frequently selected for the insertion of aberrant and 
 rudimentary tendon slips, as instanced by the Dorso-epitroch- 
 learis and Chondro-epitrochlearis muscles. 
 
 The supposition that the variation just mentioned and some 
 of the previousl}^ described bicipital variations can be brought, 
 into connection with aberrant pectoral muscle or tendon slips 
 is refuted by the constant connection with the capsule, and by 
 means of the same with the glenoid margin of the scapula. 
 
 The pectoral varieties described as Chondro-humeral, Chondro- 
 coracoid and Chondro-epitrochlear muscles are connected, at 
 times with the lower border of the pectoral muscle and tendon, 
 but they are evidently derivatives from the pectoral plane, and 
 never assume the characteristic relation to the deep surface of 
 the pectoral tendon and shoulder capsule exhibited by the bi- 
 cipital variations above described. 
 
 I have met with four well-marked instances of the Gleno- 
 epitrochlear tendon in the series examined. 
 
 Cases : 
 
248 TRANSACTIONS OF THE [MAY 13, 
 
 1. <?, Germany, net. 66. January 11, 1894. 
 Plate XXXII. Left upper extremity- 
 
 Glenoid tendon, overlying long Biceps tendon and fusing with 
 the under surface of the Pectoralis major tendon in its broad 
 upper part. About the middle of the pectoral tendon this 
 connection ceases, and the tendon bundle becomes narrower and 
 more sharply defined. It remains tendinous throughout and 
 passes obliquel}' downward and inward over the Biceps, median 
 nerve and brachial artery to be attached to the anterior aspect 
 of the internal epicondyle. 
 
 In confirmation of the view expressed as to the nature of this 
 variation the right upper extremit}' of the same subject pre- 
 sented the Capsulo-pectoral slip, as a well-marked tendon, con- 
 nected with the deep surface of the Pectoralis major; also a 
 separate slender tendon from the coraco-acromial ligament to 
 the outer margin of the short bicipital head. 
 
 2. ,?, Ireland, aet. 42. November 13, 1894. 
 Plate XXXIII. Left upper extremity. 
 
 A tendon from the glenoid margin, interwoven with the cap- 
 sule of the shoulder joint, passes over the long Biceps tendon, 
 covered by the Pectoralis major tendon, to the deep surface of 
 which it is partially attached, and continues bevond the pectoral 
 tendon as a slender but very distinct band, passing obliquely 
 downward and inward over the brachial artery and the large 
 nerves to the internal epicondyle, blending with the lower quarter 
 of Struther's ligament. 
 
 3. (?, Germany, aet. 66. January 11, 1894. 
 
 Left upper extremity presents exactly the same arrangement. 
 
 4. ,?, U. S., white, aet. 23. January'30, 1894. 
 Right upper extremity. 
 
 Gleno-ulnar fibres, rather weak in upper portion, on posterior 
 surface of Pectoralis major tendon. 
 
 From the lower part of the posterior surface of pectoral 
 tendon, and from inferior border of deep reflected part, fibres 
 are derived which form a slender tendon, passing down and in, 
 superficial to and obliquely across Biceps and brachial vessels 
 :and nerves, to be inserted on the anterior surface of the internal 
 .epicondyle. 
 
 4. M. Brachio-ulanris lateralis. 
 
 I have placed under this designation certain of the variations 
 of the Biceps, constituting accessory third humeral heads, aris- 
 ing from the anterior or external surface of the shaft, because a 
 careful examination atlords grounds for regarding them as dis- 
 tal portions of a Gleno-ulnar muscle, which has lost its proximal 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 249 
 
 or origin portion, represented by the variations just described, 
 and has obtained a secondary attachment to the humerus near 
 the bicipital groove and the insertion of the Pectoralis major. 
 
 This group would therefore form the last of a series of varia- 
 tions of a muscle arising from the glenoid margin and finding 
 its insertion at the ulnar border of the forearm. 
 
 Cases : 
 
 1. 9, Ireland, aet. 21. October 25, 1893. 
 
 Plate XXXIY. Both upper extremities present the same 
 Tariation. 
 
 A third additional Biceps head arises from the outer surface 
 of the humeral shaft and capsule of the shoulder joint, and from 
 s, strong tendinous band into which the upper fibres of a Coraco- 
 brachialis brevis are inserted. 
 
 The connections with the shoulder capsule, found in the Cap- 
 s-ulo-pectoral, Gleno-ulnar and Gleno-epitrochlear variations, is 
 retained in this instance as one of the points of origin of the 
 accesssory head. 
 
 2. 9, It. S. negro, aet. 24. December 2t, 1893. 
 Plate XXXY. Right upper extremity. 
 
 A third bicipital head arises from the anterior surface of the 
 shaft of the humerus, almost directly continuous with the lower 
 margin of the Pectoralis major tendon and attached to the lower 
 portion of the bicipital groove. 
 
 The muscle passes down on the outer side of the arm, sepa- 
 rated from the upper and outer portion of the Brachialis anticns 
 by some branches of the musculo-cutaneous nerve and muscular 
 arterial branches. It then turns inwards beneath the main 
 muscle to join the common tendon on the deep aspect and along 
 the ulnar margin. 
 
 5. Combination of Capsulo-pectoral or Gleno-ulnar with 
 
 Gleno-epitrochlear fibres. 
 Case: 
 
 $, U. S., white, aet 23. January 80, 1894. 
 The two extremities present the variations already described 
 as follows: 
 
 Right upper. Gleno-epitrochlear tendon (No. 4). 
 
 Left upper. Gleno-ulnar muscle, " a," No. 6, Plate XXY. 
 
 6. Combination of Tendinous Gleno-ulnar and Coraco-Epi- 
 
 trochlear. 
 Case: 
 
 9, Ireland, aet. 72. January 9, 1894. 
 Plate XXXYI. Right upper extremity. 
 
250 TRANSACTIONS OF THE [MAY 13, 
 
 A slightly markt'd tenclinous gleno-ulnav slip passes from the 
 capsule of the *^houldel• over the intertubercular groove, with 
 intermediate attachment to deep surface of pectoral tendon, to 
 the angle of union between the long and short bicipital heads. 
 
 Fiom the anterior surface of the lower part of the Coraco- 
 brachialis, near its insertion, is derived a slender muscle-sMp, 
 which, becoming tendinous, passes obliquely down and in over 
 brachial vessels and median nerve to be attached to the internal 
 epicondyle. 
 
 The left upper extremity' of the same subject presents a small 
 tendinous band passing from the capsule to the deep surface of 
 the Pectoralis major tendon. 
 
 II. Coraco-Ulnar Head. 
 
 This muscle is found usually very closely fused in its proxi- 
 mal part with the short or corao-radial head of the Biceps, and 
 with the Coraco brachialis. But its distal portion appears fre- 
 quently as the " third internal humeral head.''"' 
 
 The following variations are to be noted : 
 
 1. Capsula-intermediate Tendon. 
 
 Oriijin: Tendon fibres derived from the capsule of the 
 shoulder joint between the coracoid process and bicipital groove. 
 The slip passes down to the angle of fusion between the long 
 and short heads of the Biceps. 
 
 Cases : 
 
 In combination with capsulo-pectoral fibres in the following 
 previously described instances : 
 
 1. ^ , IJ. S., negro, aet. -SO. December 14, 1893. 
 "2%"No. 4. Plate XXIV. Well marked on right side. 
 
 2. S , Ireland, act. 32. iNovember 29, 1893. 
 
 "2^" No. 2. Plate XXVII. Especially well marked on left side. 
 
 3. $ , Germany, aet. 66. January 11, 1894. 
 Right upper extremity. '' 3 " No. 1. 
 Additional cases. 
 
 4. 9, Italy, aet. 3U. October 31, 1893. 
 Both upper extremities. 
 
 A strong fibro-tendinous band arising from the inner part of 
 the capsule of the shoulder passes vertically down to be attached 
 to the septum between the long and short Biceps heads. 
 
 5. ^, U. S., white, aet. 27. December 31, 1893. 
 Right upper extremit}'. 
 
 Slender tendon from inner part of shoulder capsule to outer 
 margin of lesser bicipital head. 
 
1895.] NEW YORK ACADEMY OP SCIENCES. 251 
 
 Macalister * describes several varieties of additional coracoid 
 heads of the Biceps (catalogue numbers 11-14 incL). The ac- 
 cessory portion maj^ join the main body of the muscle, or else it 
 may unite with the normal coracoid head, before that portion of 
 the Biceps joins the long head. Additional coracoid origins 
 from the Coraco-acromial ligament and from the insertion tendon 
 of the Pectoralis minor are also mentioned by the same author. 
 
 2. CoRACO-EPITROCHLARIS. 
 
 As in the case of the Gleno-ulnar head certain instances occur 
 in which an additional coracoid head passes to the internal epi- 
 condyle. I have met this arrangement in two forms : 
 
 a. Goraco-eintrochlear tendon. 
 
 Cases : 
 
 1. ^ , U. S. white, aet. 47. March, 1894. 
 Plate XXXYII. Right upper extremity. 
 
 A slender, firm tendon arises from the coracoid process at the 
 inner border of the short bicipital head and superficial to the 
 Coraco-brachialis origin. It passes downward and slightly in- 
 ward obliquely over the brachial artery and the large nerves, 
 receives near the elbow an accession of fibres from the internal 
 intermuscular septum, and is inserted into the internal epicon- 
 dyle. 
 
 2. ^ , Ireland, aet. 63. November 14, 1894. 
 Right upper extremity : 
 
 A thin tendinous slip arises from the intermuscular septum 
 betwteen the short head of the Biceps and the Coraco-brachialis, 
 passes downward and inward, over the musculo-cutaneous nerve 
 to the internal epicondj^le. 
 
 The musculo-cutaneous nerve passes entirely below the Cor- 
 aco-brachialis, between this muscle and the short bicipital head, 
 the former receiving its nerve higher up by a separate branch 
 from the outer cord of the brachial plexus. 
 
 3. ^, TJ. S. white, aet. 34. February 1, 1894. 
 Left upper extremity : 
 
 A tendon slip arises from the coracoid process and tendon of 
 origin of the Coraco-brachialis and short bicipital head ; becom- 
 ing free about 2 cm. below the coracoid it passes downward and 
 inward as a distinct tendon to be inserted into the internal 
 epicondjde. 
 
 4. ^ , TJ. S. white, aet. 39. December 14, 1893. 
 Left upper extremity : 
 
 A tendon slip from origin of Coraco-brachialis and short head 
 
 * Op. cit., p. 80. 
 
252 TRANSACTIONS OF THE [MAY 13, 
 
 of Biceps crosses over the brachial vessels and the nerves to 
 the internal epicondyle. 
 
 The long tendon of the Biceps in this arm is doubled. 
 
 5. ?, Ireland, aet. 72. January 9th, 1894. 
 
 Combined with tendinous Gleno-ulnar band in right arm (vide 
 I. 6, Plate XXXVI). 
 
 b. Coraco-epitrochlear and Gleno-epitrochlear tendon combined. 
 Case : 
 
 S, U. S., white, aet. 46. November 11, 1893. 
 
 Plate XXXVIII. Right upper extremity. 
 
 A coraco-epitrochlear tendon, arising from Coracoid process 
 at point of junction between Coraco-brachialis and short bicipital 
 head, passes down as above described over the brachial vessels 
 and the large nerves, and is joined at about the middle of the 
 arm l^v a second similar tendon which arises from the outer por- 
 tion of the capsule of the joint, descends beneath Pectoralis 
 major tendon and then crosses obliquely down and in over the 
 short bicipital muscle. The conjoined tendons continue down- 
 ward in the line of the Internal intermuscular Septum and are 
 inserted as a single band into the internal epicondyle. 
 
 c. M. Coraco-epitrochlearis. 
 Case : 
 
 .? , Germany, aet. 29. January 11, 1894. 
 
 Plate XXXIX. Left upper extremity. 
 
 A slender superficial tendon arising from the coracoid process 
 develops a thin fusiform muscle at about the middle of the arm, 
 which passes down to the internal epicondyle, lying upon the 
 brachial vessels and the large nerves. 
 
 The obvious connection of the Coraco-epitrochlear variations 
 first described with the Coraco-brachialis inferior will be consid- 
 ered in dealing with the relation of the Biceps to that muscle. 
 
 3. M. Brachio-ulnaris Medialis. 
 
 Under this head I have placed the variations which include a 
 third bicipital head, arising from the inner surface of the shaft 
 of the humerus, either from the interval between the Coraco- 
 brachialis and Brachialis anticus, or directly from the latter 
 muscle, or from the insertion of the Coraco-brachialis and con- 
 tinuous with that muscle. 
 
 It has seemed to me, in examining carefully this frequent vari- 
 ation, that we have to deal here with a Coraco-ulnar head which 
 has lost its girdle attachment and has transferred its origin to 
 the shaft of the humerus, modifjing its insertion b^- joining the 
 remainder of the Biceps muscle. 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 253 
 
 The relation of this variation to the Brachialis anticus and 
 Coraco-brachialis is obvious and will be referred to below. 
 
 In the above series I have encountered this third internal 
 head in the following instances : 
 
 1. (?, England, aet. 73. Januarj^ 11, 1894. 
 Left upper extremity. 
 
 Internal bicipital head derived directly from the humerus, ex- 
 ternal to and about 5 cm. above the Coraco-brachialis insertion, 
 between it and the Brachialis anticus, completely free from the 
 latter muscle. 
 
 The musculo-cutaneous nerve, after pjercing the Coraco-bra- 
 chialis, passes between the additional head and the main portion 
 of the Biceps muscle. 
 
 2. (?, Ireland, aet. 46. January 11, 1894. 
 
 Third internal bicipital head arising from the outer margin of 
 the Coraco-brachialis insertion, and in close connection with the 
 superior and internal origin of the Brachialis anticus. 
 
 3. S- , Ireland, aet. 37. October 17, 1893. 
 Right upper extremity. 
 
 Third bicipital head arising from inner surface of shaft of hu- 
 merus at the Coraco-brachialis insertion. Separated from the 
 main Biceps muscle by the large muscular branches of the mus- 
 culo-cutaneous nerve, which perforates the Coraco-brachialis. 
 
 The internal head has further been noted in the following 
 cases : 
 
 4. $ , Ireland, aet. 46. January 24, 1894. 
 Right upper extremity. 
 
 5. $, Ireland, aet. 62. November 28, 1893. 
 Right upper extremity. 
 
 6. ^, Germany, aet. 28. October 5, 1893. 
 Left upper extremity. 
 
 Additional head, derived in this instance from the insertion of 
 the Coraco-brachialis, goes mainly into the semilunar fascia. 
 
 7. 9, Germany, aet. 84. November 9, 1893. 
 Left upper extremity. 
 
 8. 9, IJ. S., white, aet. 68. November 22, 1893. 
 Right upper extremity. 
 
 Small third internal head, derived chiefly from the tendon of 
 of the Coraco-brachialis, with which it is continuous. 
 
 9. ^ , Germany, aet. 60. December 14, 1893. 
 Right upper extremity. 
 
 10. ^ , Bohemia, aet. 30, December 19, 1893. 
 Left upper extremit3\ 
 
 11. $, Italy, aet. 40. December 14, 1893. 
 Right upper extremity. 
 
254 TRANSACTIONS OF THE [MAY 13, 
 
 II. Relation of biceps to the adjoining deep ventro-appendic- 
 
 ULAR fibres of THE CORACO-BRACHIALIS, AND, III. TO THE 
 
 DEEP INTRINSIC FLEXOR OF FOREARM, BRACHIALIS 
 
 ANTICUS. 
 
 The consideration of the variations, described above as the 
 Humero-ulnar internal head and the Coraco-epitroehlear slips, in- 
 dicate the intimate relation existing between the Biceps and the 
 Brachialis anticns and Coraco-brachialis. 
 
 Hnmphry,* in describing the muscles of the Cryptobranch, 
 accentuates the close relation of the Coraco-brachialis longus 
 and Biceps of this animal. He finds that the former muscle 
 divides into two portions, one of which is inserted into the 
 ulnar edge of the humerus ; the other, being nearly as large, is 
 partly inserted into the side of the long tendon of the Biceps, 
 while a bundle of its fibres continues over the elbow and is in- 
 serted into the ulna near the joint. Humphry regards this lat- 
 ter portion as the representative of the short or coracoid bicip- 
 ital origin in man. 
 
 We find in this instance on the one hand the direct union of 
 the Coraco-brachialis with the Biceps, and on the other insertion 
 of part of the muscle into the ulna. 
 
 Again the Brachialis anticns is in some forms (Pteropus) 
 found to be in direct continuity with the Coraco-humeral, f and 
 in the Seine the Biceps derives two factors from the humerus, 
 which occupy the position of the Brachialis anticns and are so 
 named b3' Riidinger. Humphry sums the mutual relations of 
 these three muscles up as follows : 
 
 " They show the Biceps to be an intermediate between the 
 Coraco-humerals and Brachialis anticus, continuous with either 
 or both, and uniting them into one group, extending from the 
 coracoid, along the ulnar and palmar surface of the humerus, 
 to the radius and ulna." 
 
 I believe that we may properlv regard the variations of the 
 Biceps above referred to in this light. Both the Coraco-epi- 
 troehlear slips and the Internal humeral heads speak for the 
 original unity of a muscular plane extending between coracoid 
 and ulna. 
 
 The separation of the radius as the rotatory- element of the 
 forearm and hand, and the assignment of the corresponding 
 muscular function to the Biceps, have caused the elimination of 
 the ulnar segment of the muscle, leaving the Brachialis anticus 
 as the deep intrinsic flexor connected with the ulna, and reduc- 
 
 ♦ Op. cit., p. 33. 
 
 t Humphry, op. cit., p. 164. 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 255 
 
 ing the Coraco-brachialis to a deep ventro-appendicular muscle 
 confined in its insertion to the humerus. 
 
 It is only in the Third Internal humeral head of the Biceps, 
 and in the Coraco-epitrochlear slips, that we still find the evi- 
 dence of the original connection between these muscles, and see 
 the reversion of the Biceps toward its lost ulnar segment. 
 
 It is onl}^ necessar}^ to refer in this connection to the interest- 
 ing account of the structure of the Coraco-brachialis given by 
 Prof. Wood,* and to point out the significance of the occasional 
 Coraco-brachialis longus. 
 
 Analysis of cases of Quadriceps flexor cubiti and evidences 
 of the ulnar tendency of the Bicejys in variations of the insertion. 
 
 In the above series five examples of a four-headed muscle 
 have been encountered. 
 
 1. ^, Ireland, aet. 45. January 9, 1894. 
 Plate XL. Right upper extremity. 
 
 A third additional head (gleno-ulnar) arises by a flat tendon 
 from the capsule of the shoulder-joint, between the long and 
 coracoid heads. It is separated above from the main muscle by 
 the muscuto-cutaneous nerve, after the latter has perforated the 
 Coraco-brachialis. A fourth additional head (coraco-ulnar) 
 arises from the inner surface of the shaft of the humerus, almost 
 directl}^ continuous with the Coraco-brachialis at its insertion, 
 and separated from the Brachialis anticus b}^ a branch to the lat- 
 ter muscle from the musculo-cutaneous nerve. 
 
 The left upper extremity of the same subject presents the addi- 
 tional internal humeral head from the Coraco-brachial insertion. 
 
 The case affords an example of the typical composition of the 
 four-headed muscle. The gleno-ulnar head passes to the deep 
 and ulnar surface of the main muscle, which is joined lower down 
 by the coraco-ulnar, the continuity of the latter with the Coraco- 
 brachialis being well marked. The superficial part of the muscle 
 is constituted by the large gleno- and coraco-radial heads. 
 
 2. 9, Ireland, aet 40. October 25, 1894. 
 
 Plate XLI. Both upper extremities present the same ar- 
 rangement. 
 
 A third anomalous head arises from the glenoid margin and 
 capsule of the shoulder, passes down over the bicipital groove, 
 covering the tendon of the long head, supplied by a branch from 
 the musculo-cutaneous nerve, after, the same has perforated the 
 Coraco-brachialis. A fourth additional head arises from the 
 humerus, along the outer margin of the tendinous Coraco-brach- 
 ialis insertion. 
 
 The main portion of the musculo-cutaneous nerve, after per- 
 
 * Journal of Anatomy and Physiology, Vol. I., p. 44, 1867. 
 
256 TRANSACTIONS OF THE [MAY 13, 
 
 fornting the Coraeo-brtichialis, passes first between the 3(1 and 
 4th additional heads, and subse(iuently turns down to lie be- 
 tween the accessory heads, a short distance above their junction 
 with the tendon of insertion, and the BrachinMs anticus. 
 
 The semilunar fascia is well developed, scattered fibres ex- 
 tending up over the brachial artery- as high as the internal 
 epicondyle. 
 
 This case only dirters from the preceding one in the separa- 
 tion of the fourth accessory head from the Coraco-brachialis. 
 
 3. ^, Germany, aet. 62. ' November 29, 1894. 
 Plate XLII. Right upper extremity. 
 
 A combination of an additional gleno-ulnar head with inter- 
 mediate pectoral tendon attachment, and a fourth internal hu- 
 meral head, arising between the Coraco-brachialis and Brachialis 
 anticus. 
 
 The insertion is peculiar. The radial tendon is formed b}- the 
 long head (gleno-radial) and by the deep portion of the coracoid 
 and additional internal humeral heads (coraco-radial). The re- 
 maining superficial portion of the regular coracoid and of the 
 internal humeral head (coraco-ulnar) is joined bj^ the entire ad- 
 ditional glenoid muscle (gleno-ulnar) and passes superficially 
 inward into a strong tendinous semilunar fascia which is well 
 separated from the radial tendon. 
 
 4. J, U. S. white, aet. G3. November 7, 1894. 
 Plate XLII I. Right upper extremity. 
 
 The gleno-radial and gleno-ulnar heads are well defined at 
 their origin, fusing before meeting the coracoid segment. The 
 4th head is derived from the outer margin of the regular 
 coracoid head (coraco-radial?), 5 cm. below level of lesser 
 tuberosity', as a slender slip, about 10 cm. long, which joins the 
 inner margin of the glenoid portion, before the latter fuses with 
 the main coracoid muscle. 
 
 5. 9, U. S. white, aet. 26. November 28, 1894. 
 Plate XLIY. Left upper extremity'. 
 
 A third internal humeral head arises from the shaft of the 
 humerus at the Coraco-brachialis insertion and joins the regular 
 coracoid head along its ulnar margin, 2.5 cm. above the level of 
 the elbow. (Coraco-radial and Coraco-ulnar). 
 
 The fourth head (gleno-ulnar) is derived from the long ten- 
 don, along its outer margin, under cover of the Pectoralis, b\- a 
 tendon which becomes muscular at the lower border of the 
 pectoral tendon and fuses about the middle of the arm with the 
 external and anterior part of the Brachialis anticus. 
 
 Macalister * has fonnd a similar slip once. 
 
 * Op. cit., p. 83. 
 
1895.] NEW YORK. ACADEMY OF SCIENCES. 257 
 
 The variation is interesting as affording an instance of con- 
 tinuity of the Biceps with the Brachialis anticus, and hence of 
 a direct ulnar destination of some of tlie bicipital glenoid fibres. 
 
 Variations of insertion pointing to ulnar attachment of Biceps. 
 
 1. ^, Assyria, aet. 28. November 15, 1894. 
 Plate XLY. Right upper extremity". 
 
 A muscular belly, entirely separate from Brachialis anticus, 
 arises from the lower part of the inner margin of the humeral 
 shaft, and passes downwards and outwards, underneath the Bi- 
 ceps, dividing into two portions. The internal division passes 
 to reinforce the semilunar fascia ; the external stronger bundle 
 dips into the cubital fossa to the inner side of the radial Biceps 
 tendon, joining it, and giving some fibres to the fascia of the 
 Supinator brevis. The additional muscle in this instance is e\i- 
 dently a compound of portions of both Coraco-radial and Coraco- 
 ulnar, whose origin has shifted downwards to the humeral 
 shaft, the proximal portion remaining as the coraeoid head of 
 the regular Biceps and the Coraco-brachialis. 
 
 The compound character of both the external radial tendon of 
 the Biceps and of the semilunar fascia (internal or ulnar tendon) 
 is well shown bj' this case. 
 
 2. $, Ireland, aet. 57. October 7, 1893. 
 Right upper. 
 
 Tendon slip from radial biceps insertion into lesser head of 
 Pronator teres. 
 
 3. $ , Germany, aet. 58. January 23, 1894. 
 Right upper. 
 
 Tendon slip from radial Biceps tendon into Pronator teres and 
 deep fascia of forearm. 
 
 Macalister * describes insertions of the Biceps into the coro- 
 noid process, Pronator teres, Coronoid insertion of Brachialis 
 anticus, capsule of elbow and the origin of some of the flexor 
 muscles. 
 
 While completing this paper a number of additional bicipital 
 variations, bearing out the views expressed relative to the com- 
 position of the muscle, have come under observation. Among 
 them the two following instances illustrate some of the import- 
 ant morphological features of the muscle so well that the}' are 
 added to this paper. - 
 
 1. ^ , Ireland, aet. 67. January 22, 1895. 
 
 Plate XLYI. Left upper extremity. 
 
 /. Glenoid Heads. 
 
 The outer bicipital head (Gleno-radial) is well developed. In 
 its upper portion the tendon is overlapped by a distinct band, 
 
 * Op. cit, p. 83. 
 
258 TRANSACTIONS OF THE [MAY 18, 
 
 arising from the cai)sule of the slioulder joint and attached to 
 the deep surface of the Pectoralis major tendon (Capsulo-pec- 
 toral variety of Glono-ulnar liead). Ahout 4 cm. above the 
 elbow joint a slip separates from the inner border and deep sur- 
 face of the main muscle, and, becomini; tendinous, passes down- 
 ward and inward to the anterior border of the ulna, just below 
 the coracoid insertion of the Brachialis anticus. (Persistent dis- 
 tal portion of Gleno-ulnar division). 
 
 II. Coracoid Heads. 
 
 A broad muscle, arising with the Coraco-brachialis from the 
 coracoid i)rocess, divides at the level of the lower Pectoralis 
 margin into : (a) The usual short or coracoid head, which passes 
 down and out and joins the outer head a little above the middle 
 of the arm (^Coraco-radial division'), (b). An internal muscle, 
 completely free from Coraco-brachialis, which immediately sub- 
 divides into two equal portions. Of these the posterior and in- 
 ternal muscle descends vertically over the Coraco-brachialis in- 
 sertion, and terminates at the junction of middle and lower one- 
 third of the arm in a strong tendon, which passes down, at first 
 free and subsequently fused with Struther's ligament, to the in- 
 ternal epicondyle. {Goraco-epitrochUar varietij of Gleno-ulnar 
 head. 
 
 The anterior muscle, lying upon the Brachialis anticus and the 
 internal intermuscular septum, remains completely free from 
 surrounding structures and terminates in a strong tendon which 
 passes over the elbow joint and is inserted into the coronoid 
 process of the ulna, just internal to the Brachialis anticus inser- 
 tion. {Typical Goraco-ulnar head of muscle.) 
 
 This case is especially important, as it presents not only the 
 more common proximal vestiges of the obsolete ulnar divisions, 
 but also exhibits perfectly the rare distal or insertion portions, 
 in their complete form, attached to the ulna. 
 
 The separation of the Biceps insertion from the ulna and the 
 assignment of the muscle, as a supinator, to the radius, would 
 lead us to expect this disproportion, as regards frequency of oc- 
 currence, between reversions of the complete distal and proxi- 
 mal segments of the lost ulnar division. The distal or inser- 
 tion portion of the ulnar division w^as the first to disappear at 
 the insertion into the ulna, and consequently reverts in a very 
 much smaller percentage in its complete form than the proxi- 
 mal or origin portion, whose existence has, so to speak, been 
 prolonged by the opportunit}' of uniting with the radial division. 
 
 The above instance exhibits these features of the muscle-plan 
 perfectly, and the preparation has been added to the Variation- 
 series of the Morphological Museum of Columbia College. 
 
1895.] NEW YORK ACADEMY OF SCIENCES. 259 
 
 2. The second case, recently observed, which presents points 
 of especial interest in connection with the subject of this paper, 
 exhibits one of the important relations between Biceps and 
 Brachialis anticus, and emphasizes the significance of the semi- 
 lunar fascia, as representing the remains of an ulnar bicipital 
 division which has lost its skeletal attachment, in accordance 
 with the functional specialization of the muscle as the main 
 supinator of the limb. 
 
 $ , Ireland, aet. 54. March 15, 1895. 
 
 Plate XLVII. Right upper extremity : 
 
 This case affords a well-marked example of the original con- 
 nection between Biceps and Brachialis anticus. 
 
 The origin of the Biceps in this arm is normal, as is the ar- 
 rangement of Coraco-brachialis. A strong muscular bundle 
 separates from Brachialis anticus a short distance below the 
 Coracobrachial insertion. The outer and larger portion of this 
 muscle joins the deep surface of the Biceps and passes with it 
 to the radial insertion. The inner part continues downward 
 and inward, gives off a narrow tendon which passes with the 
 remainder of Brachialis anticus to the coronoid process, and 
 then expands into the semilunar fascia, which is well developed, 
 crossing obliquely over the brachial artery. 
 
 The additional muscle in this instance is evidently an Internal 
 Brachio-ulnar muscle, which, however, presents not only the 
 usual connection with the radius by means of the bicipital 
 junction, but preserves its original ulnar insertion both by the 
 tendon slip to the coronoid process and by the development of 
 the entire semilunar fascia. The significence of the latter 
 structure, entitling it to be considered as the distal portion of 
 an ulnar bicipital segment which has lost its skeletal attachment, 
 is strongly emphasized by the arrangement of the aberrant 
 muscle in this subject. 
 
PLATE XVIII. 
 
 Right upper extremity. 
 
 9 , white, U. S. aet. 62. 
 
 Gleno-uhiar head ; var. 1, Capsulo-pectoral teudon. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XVIII. 
 
PLATE XIX. 
 
 Eight shoulder joint of same subject, opened from behind, head of hu- 
 morus removed, sho\ving thickening of anterior capsule wall by the Cap- 
 sulo-pectoral tendon. 
 
Tkans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XIX. 
 
 ^ 
 
H92 
 
 Huntington 
 
 Bigni . fir&anee— fyf muRfiu laiL. 
 
 variation. 
 
 16 
 
 <r 
 
 . '' ii ' i ' jwwf^Mv^^V^ ^" 
 
 •'i-m.mfm 
 
 jS^i^. 
 
PLATE XX. 
 
 Right upper extremity. 
 
 <? , Austria, aet. ()5. 
 
 Gleuo-uluar head ; var. 1, Capsulo-pectoral teiulou. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XI^^, PL. XX. 
 
PLATE XXI. 
 
 Eight upper extremity. 
 
 9 , Gennany, aet. 84. 
 
 Gleno-uhiar head, var. 1, Capsulo-pectoval temlon. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXI. 
 
 V. 
 
 :¥i fij 
 
 ■-.,..;: f»»^ 
 
PLATE XXII. 
 
 Eight upper extremity. 
 $ , U. S. white, aet. 24. 
 Gleno-ulnar head, var. "ia, Gleuo-nlnar muscle. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXII. 
 
PLATE XXIII. 
 
 Right upper extremity. 
 ^, U. S. -white, aet. 50. 
 Gleno-iilnar liead, var. 2a, Gleno-ulnav muscle. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIY., Pl. XXIII. 
 
PLATE XXIV. 
 
 Right upper extremity. 
 $ , r. S. negro, aet. 50. 
 Gleiio-uluar head, var. 2a, Gleno-uhiar muscle. 
 
Teans. N. y. Acad. Sci. 
 
 Vol. XIV., Pl. XXIV. 
 
PLATE XXV. 
 
 Left upper extremity. 
 9 , U. S. white, aet. 23. 
 Gleuo-ulnar head, var. ■2a, Gleno-ulnar muscle. 
 
Teaks. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXV. 
 
PLATE XXVI. 
 
 Left upper extremity. 
 
 ,y , U. S. negro, aet. 50. 
 
 Gleno-ulnar head, var. "ib, Gleno-nhiar innscle. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXVI. 
 
PLATE XX VII. 
 
 Eight upper extremity. 
 
 $, Ireland, aet. 3:2. 
 
 Gleno-ulnar head, \a\\ 2b, Gleno-ulnar muscle. 
 
Teaks. N. Y. Acad. Sci. 
 
 Vol. XI v., Pl. XXVII. 
 
 /■A-, 
 
PLATE XXVIII. 
 
 Left upper extremity' of preceding subject. 
 
 ^ , Ireland, aet. 32. 
 
 Gleno-uluar, head, var. 2a, Gleuo-ulnar muscle. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XXVIII. 
 
 -^%, 
 
 \y 
 
 M^'V: 
 
PLATE XXIX. 
 
 Left upper extremity. 
 
 $ , Ireland, aet. 53. 
 
 Gleuo-uhiar head, var. 2c, transition forms and variations. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XXIX. 
 
PLATE XXX. 
 
 Left upper extremity. 
 
 $ , Ireland, act. 35. 
 
 Gleno-ulnar head, var. '2q, transition forms and variations. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXX. 
 
 / / 
 
PLATE XXXI. 
 
 Right upper extremity. 
 
 $, Germany, aet. 64. 
 
 Gleno-ulnar head, var. '2c, transition forms and variations. 
 
Tean-s. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XXXI. 
 
PLATE XXXII. 
 
 Left ui>i)er extieniity. 
 $ , Germany, aet. 66. 
 Gleuo-ulnar head, var. 3, Gleno-epitroclilear tendou. 
 
Trans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XXXII. 
 
 m^l'**^ 
 
 \ 
 
 ■N 
 
 ;'M/ 
 
PLATE XXXIII. 
 
 Left upper extremity. 
 
 <? , Ireland, aet. 42. 
 
 Gleiio-ulnar head, var. 3, Gleno-epitrochlear tendon. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XXXIII. 
 
PLATE XXXIV. 
 
 Right upper extremity. 
 
 9, Ireland, aet. 27. 
 
 Gleno-ulnar heiid, var. 4, M. Brachio-ulnaris lateralis. 
 
Teaks. N. Y. Acad. Scr. 
 
 Vol. XIV., Pl. XXXIV. 
 
 I 5 
 
 lliS'- 
 
PLATE XXXV. 
 
 • Eifjht upper extremity. 
 9 , U. S. negro, aet. 34. 
 Gleno-ulnar lieiid, var. 4, 'Si. Braehio-uliuiris lateralis. 
 
Teans. N. Y. Acad. Scr. 
 
 Vol. XIV., Pl. XXXV. 
 
PLATK XXXVI. 
 
 Eifilit upper extremity. 
 9, Ireland, aet. 72. 
 
 Gleno-ulnar head, var. 6, combination of tendinous Gleno-ulnar and Cor- 
 aco-epitroclilear. 
 
Trans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXXVI 
 
 
 
 V 
 
PLATE XXXVII. 
 
 Riflht upper extremity. 
 ^, U. S. ^vhite, aet. 47. 
 Coraco-ulnar head, var. 2a, Coraco-epitrochlear tendon. 
 
Teaks. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXXVII. 
 
PLATE XXXYIII. 
 
 Eight upper extremitj'. 
 ^, U. S. white, aet. 46. 
 
 Coraco-ulnar head, var. 2b, Coraco-epi trochlear and Gleno-epitrochlear ten- 
 dons combined. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXXVIII. 
 
PLATE XXXIX. 
 
 Left upper extremitv. 
 S, Gemiauy, aet. 29. 
 Coraco-uluar liead, -var. 2c, M. Coracorepitrochlearis. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XXXIX. 
 
TLATE XL. 
 
 Right upper extremity. 
 
 $ , Ireland, aet. 45. 
 
 M. Quadriceps flexor cubiti. 
 
Trans. IST. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XL. 
 
PLATE XLI. 
 
 Eight upper extremity. 
 
 $ , Ireland, aet. 40. 
 
 ]\I. Quadriceps flexor cubiti. 
 
Teans. N. Y. Acad. Sct. 
 
 Vol. XIV., Pl. XLI. 
 
PLATE XLII. 
 
 Right upper extremity. 
 
 $ , Germany, aet. 62. 
 
 M. Quadriceps flexor cubiti. 
 
Teans. N. Y. Acad. Sct. 
 
 Vol. XIV., PL. XLH. 
 
 C 
 
PLATE XLIII. 
 
 Right upper extremity. 
 $ , U. S. white, aet. 63. 
 M. Quadriceps flexor cubiti. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XLIII. 
 
PLATE XLIV. 
 
 Left upper extremity. 
 9 , U. S. white, aet. 26. 
 M. Quatlriceps flexor cubiti. 
 
Tbaks. N. Y. Acad, Sci. 
 
 Vol. XJV., Pl. XLIV. 
 
PLATE XLV. 
 
 Right upper extremity. 
 
 S, Assyria, aet. 28. 
 
 M. Brachialis accessorius, joining insertion of Biceps. 
 
Teans. N. Y. Acad. Sci. 
 
 Vol. XIV., PL. XLV. 
 
PLATE XLVI. 
 
 Left upper extremity. 
 S, Ireland, aet. 67. 
 
 Gleno-uluar and Coraco-uluar muscles, complete form, with distal por- 
 tions persistent. 
 
Teaks. N. Y. Acad. Sci. 
 
 Vol. XIV., Pl. XLVI. 
 
PLATE XLVII. 
 
 Right upper extremity. 
 9 , Ireland, aet. 54. 
 
 Connection of Biceps and Brachialis anticus, with complete derivation of 
 semilunar fascia from the latter muscle. 
 
Trans. N. Y. Acad. Sot. 
 
 Vol. XIV., Pl. XLVII. 
 
 I