220 



THE MUSCLES OF THE UPPER LIMB. 



humerus, from the bicipital groove, or from the great tuberosity. In rarer cases two supple- 

 mentary heads are present, arising from different parts of the humerus ; and in a few 

 instances three supplementary heads have been seen, making a five-headed muscle. Occasion- 

 ally a fleshy slip is given off from the inner border of the muscle to the internal inter- 

 muscular septum, or to the internal condyle, passing over the brachial artery ; and fasciculi 

 have been seen passing to the pronator teres and to the brachialis anticus. In a few cases 

 absence of the long head has been observed ; in others this head has been found to be attached 

 in the bicipital groove, not extending to the scapula. 



The long head of the biceps was originally extra-articular, and its position within the 

 joint has been acquired by a gradual sinking through the capsule, various stages of which 



Fig. 234. DEEP VIEW OP THE MUSCLES OF THK 



RIGHT SHOULDER AND ARM, FROM BEFORE. 



(Allen Thomson. ) | 



a, I), outer half of the clavicle ; c, coracoid pro- 

 cess ; d and e, triangular spaces at the upper and 

 lower angles of the scapula on its antei'ior surface to 

 which the serratus magnus is attached ; f, great 

 tuberosity ; y, surface of the humerus below the 

 bicipital groove ; h, outer, and i, inner condyle ; 1 1 

 cut coracoid head, and 1', cut glenoid tendon of the 

 biceps muscle ; 2, double tendon of insertion of the 

 pectoralis major, from which a prolongation is seen 

 running up to the capsule of the shoulder ; 3, inser- 

 tion of the deltoid ; 4, coraco-brachialis ; 5, 5, 

 subscapularis ; 5', its insertion into the small tube- 

 rosity ; 6, teres major ; 6', its insertion behind and 

 below the latissimus dorsi ; 7, part of the latissi- 

 mus dorsi ; + , slip from the inferior angle of the 

 scapula ; 7', insertion of the tendon, after winding 

 round the teres major, in front of and higher than 

 that muscle ; 8 ; 8', brachialis anticus ; 9, 9, long 

 head of the triceps, at the upper part seen in the- 

 interval between the teres major and subscapulari* 

 muscles; 9', inner head ; 10, flexor profundus digi- 

 torum ; 11, tendon of insertion of the biceps. 



are represented by the condition in different 

 animals. At the same time it has become 

 covered over by the coraco-humeral ligament 

 derived from the tendon of the pectoralis minor. 

 In the human foetus of the third month the 

 tendon is attached to the capsule by a fold of 

 synovial membrane, which disappears in the 

 fourth month. 1 The semilunar fascia of the 

 biceps is probably the representative of an ulnar 

 division of the superficial flexor mass ; it cor- 

 responds to the fascial insertion of the biceps of 

 the lower limb. 



The brachialis anticus muscle arises 

 from the lower half of the front of the 



humerus and from the intermuscular septa of the arm. At the upper part of its- 

 origin it embraces the insertion of the deltoid by two angular fleshy processes, the 

 inner of which is short and thin, while the outer extends upwards, occupying the 

 larger division of the spiral groove, as far as the upper limit of the deltoid eminence 

 (fig. 91) ; it reaches downwards to the capsule of the elbow-joint, and inwards to- 

 the internal supracondylar ridge and the intermuscular septum in its whole extent ; 

 on its outer side it is separated from the intermuscular septum in the greater part of 

 its length by the supinator longus and extensor carpi radialis longior, and only arises 

 from it for a short 'distance at its upper end. It is closely adherent to the anterior 



Welcker, i; Die Einwanderung der Bicepssehne in das Schultergelenk." Arch. f. Anatomic, 1878, 20. 



