MUSCLES OF THE ANTERIOR LIMBS. 



255 



of the scapular spine, by a short aponeurosis. The superspinatus is considerable, and 

 terminates in a single branch that goes to the great trochanter. 



The subspinatus is not so large as the preceding, and is also undivided at its inferior 

 extremity : it is the inferior branch which is absent. 



The coraco-brachialis is very short, and composed of a single fasciculus, \vhich 

 terminates above the humeral insertion of the adductor of the arm. 



In the Pig, the disposition of this muscle is the same; it is, besides, very tendinous. 



COMPARISON OF THE MUSCLES OF THE SHOULDER OF MAN WITH THOSE OF ANIMALS. 



As muscles of the shoulder, there are only described the deltoid, subspinatus, teres 

 minor and major, and the subscapularis ; the coraco-brachialis being included in the 

 region of the arm, and the small scapulo-humeralis is absent (see Fig. 120). 



The deltoid, represented in part by the long abductor 

 of the arm of Solipeds, is a large, triangular, flat muscle, 

 that covers the articulation of the shoulder. Its fibres are 

 inserted into the external third of the anterior border 

 of the clavicle, the external border of the acromion, and 

 the inferior border of the scapular spine for the whole of 

 its width ; below, it is attached, through the medium of a 

 tendon, to the deltoid imprint. 



By their disposition, the superspinatus, subspinatus, 

 and subscapularis resemble the muscles of Garni vora 

 The teres major, after establishing relations with the great 

 dorsal, as in Solipeds, is fixed into the inner lip of the 

 bicipital groove. 



MUSCLES OF THE ABM. 



These muscles, grouped around the humerus, 

 are attached to the fore-arm by their inferior ex- 

 tremities. Those situated in front flex this por- 

 tion of the limb, while those behind extend it. 

 The first form the anterior brachial region, the 

 second the posterior brachial region. 



A. Anterior Brachial Region. 



This region is composed of only two muscles, 

 the long and short flexors of the fore-arm. 



1. Long Flexor of the Fore-arm or Brachial 

 Biceps. (Figs. 85, 119, 121.) 



Synonyms. Coraco-cubitalis, or coraco-radialis, accord- 

 ing to Girard. (Flexor brachii Percivall. Scapulo- or 

 coraco-radialis Leyli.) 



Preparation. Place the limb on its internal face, throw 

 back the brachial insertion of the mastoido-humeralis, 

 sterno-humeralis, and sterno-aponeuroticus, over the ex- 

 ternal muscles of the fore-arm; excise, lengthways, the 

 inferior extremity of the superspinatus, to show the 

 originating tendon of the muscle. The inferior insertion 

 may be studied with that of the short flexor muscle. 



Form Situation Direction Structure. A 

 long, cylindrical muscle, thick in its middle portion, bifid inferiorly, situated 

 in front of the humerus, in an oblique direction downwards and backwards, 

 tendinous at its two extremities, divided by a great number of strong fibrous 

 intersections, one of which, nearly central and much more considerable than 

 the others, is a very resisting cord that traverses the muscle throughout its 

 length, and becomes continuous with the tendons at its extremities. 



Attachments. This muscle has its origin at the base of the coracoid 



MUSCLES OF ANTERIOR ASPECT 

 OF MAN'S UPPER ARM. 



1, Coracoid process of scapula ; 

 2, Coraco-clavicular liga- 

 ment (trapezoid) passing up- 

 ward to clavicle ; 3, Coraco 

 acromial ligament, passing 

 to acromion; 4, Subscapu- 

 laris; 5, Teres major; 6, 

 Coraco-brachialis ; 7, Bi- 

 ceps; 8, Upper end of ra- 

 dius ; 9, Brachialis anticus ; 

 10, Internal head of triceps. 



