The; Anterior Limb. 



139 



The abductor brachii inferior should be separated from the in- 

 fraspinatus and divided, the distal end being reflected together with 

 the met acromion. 



(d) The infraspinatus. Origin: Posterior portion of the lateral 

 surface of the scapula, including the spine. Insertion: 

 Greater tubercle of the humerus. The muscle tills the 

 infraspinous fossa. 



(e) The supraspinatus. Origin : Anterior portion of the lateral 

 surface of the scapula (supraspinous fossa), supraspinous 

 fascia, and, to a certain extent, the subscapular fascia. 

 Insertion: Greater tubercle of the humerus. 



(f) The subscapularis. Origin : Entire medial surface of the 

 scapula. Insertion : Lesser tubercle of the humerus. 



(g) The teres major. Origin : 



Dorsal portion of the ^"'<"'°'- 



axillary border of the 



scapula. Insertion : In 



common with the latis- 



simus dorsi on the ante- 

 rior surface of the 



humerus, 

 (h) The teres minor. Origin : 



Ventral portion of the 



axillary border of the 



scapula. Insertion: 



Greater tubercle, 

 (i) The coracobrachialis. 



Origin : Coracoid process. 



Insertion : Distal portion 



of the upper third of the 



humerus on its medial 



surface. 



5. Muscles arising from the 

 scapula and humerus and inserted on 

 the proximal ends of the radius and 

 ulna (extensors and flexors of the 

 forearm), (Fig. 46). 



A. Extensor (anconaeus) group. 

 The muscles arise for the most part 

 behind the axis of the humerus, and 

 are inserted on the olecranon. 



(a) The extensor antibrachii 

 parvus (anconaeus quar- 



tus). Origin: Fascia of the medial surface of the humerus, 

 Insertion: Medial surface of the olecranon. 



The muscle should be divided, or detached from its origin, and re- 

 flected 



Fig. 46. Transverse section through the 

 distal portion of the arm; semidiagrammatic; 

 a.b., brachial artery ; a.c.i., radial collateral 

 artery; b., biceps: br.l. and br.m., lateral and 

 medial heads of the brachialis; d.. deltoideus 

 (insertion) ; e.a.p., extensor antibrachii 

 parvus ; f., brachial fascia ; h., humerus; 

 n.m., median nerve; n.r., radial nerve; n.u., 

 ulnar nerve; tr.l-tr.3, long, lateral, and 

 medial heads of the triceps; v.b., brachial 

 vein; v.c, cephalic vein. 



