82 THE MUSCLES. 



anatomy which arises from the costal cartilages, and more par- 

 ticularly that part which is connected with the aponeurosis of the 

 m. obliquus abdominis externns. The muscle arises (i) from the 

 m. reef its abdominis (Fig. 72 rj, that is, it forms a direct continua- 

 tion of the outer portion of this muscle ; (2) the inner, smaller part 

 arises from the superficial surface of the aponeurosis of the m. obli- 

 quus abdominis. The muscle becomes narrower as it courses out- 

 wards and forwards, the outer fibres being longer and more oblique 

 than the inner. The action of this muscle will necessarily vary 

 according to the part or parts which are brought into action; 

 speaking generally, the anterior extremities will be drawn down- 

 wards and towards each other. 



53. M. coraco-humeralis (Duges), (Figs. 72, 73 c./i.J. 

 Duges, n. 72. Klein, adductor hwmeri. 



A long, narrow muscle, lying upon the posterior border of the 

 coracoid and the lowest part of the m. siibscapularis. By its posi- 

 tion it corresponds most nearly with the m.pectoralis minor., although 

 its insertion does not. It has a narrow origin from the coracoid 

 near the sternum, whence it courses outwards, under cover of the 

 port, sternalis anterior and posterior of the m.pectoralis, to be inserted 

 into the middle of the humerus between the deltoid and internal 

 head of the triceps. It draws the limb towards the trunk. 



54. M. sternoradialis (Cuvier), (Figs. 72, 73 s.r.}. 

 Duges, pre-sterno-clavi-radial, n. 74. 



This muscle evidently represents the biceps of man, it lies in 

 front of the portio sternalis anterior of the m. pectoralis, its hinder 

 border being under cover of the latter muscle. It takes origin from 

 the episternum, omosternum, and the epicoracoid ; from this broad 

 origin the fibres converge while coursing backwards and outwards to 

 be attached to a strong tendon. This tendon plays in a groove along 

 the crista deltoidea, and is held in position by tendinous bands 

 arising from the insertion of the m. pectoralis ; it then pierces the 

 lower portion of the muscular belly of the deltoid, and is inserted 

 into the anterior extremity of the radial side of the radio-ulnar. 

 The muscle is a powerful flexor of the forearm. 



55. M. deltoideus (Figs. 70, 72, 73 d}. 

 Duges, pre-stemo-scapulo-humeral, n. 68. 



It is placed in front of and external to the m. sternoradialis, and 

 represents both the m. deltoideits and supraspinatits of man. The 

 muscle has two points of origin : 



