54 ANATOMY OF THE R.ABBIT 



(15) and the subscapularis m. (18). In man the teres are 

 antagonistic rotators of the arm, but in the rabbit they are 

 fused and have a common insertion. Transect both. 



18. Subscapularis m.: Entire medial surface of scapula; to 

 lesser tuberosity of humerus. Draws humerus mediad. Probe 

 only. 



19. Coracobrachialis m.: Coracoid process of scapula; to 

 craniomedial surface of humerus. Draws humerus mediad. 

 Do not transect. This muscle is usually short, but it is often 

 variable in length and point of insertion since it is homologous 

 with the second or coracoid head of the biceps brachii in man. 

 (Cf. biceps brachii, 20.) 



The student should now have a clear conception of the com- 

 plicated muscle and tendon, as well as ligament, relations of 

 diarthrodial joints in general and of a ball-and-socket joint (the 

 shoulder joint) in particular, so that attention may be centered 

 on the broader aspects of functional relations of muscles and 

 bones in the following descriptions of muscles. 



D. MUSCLES WHICH MOVE THE FOREARM 



(Nos. 20-22; Figs. 18, 19) 



20. Biceps brachii (b. flexor cubiti) m.: Cranial border 

 of glenoid fossa (supraglenoidal tubercle) of scapula; to proximo- 

 medial surface of radius and ulna. Draws forearm craniad. 

 Transect. This muscle has various functions besides flexing 

 the antibrachium. For instance, if the elbow joint is fixed by 

 antagonistic muscles it draws the limb craniad. Its functions, 

 though similar, are more varied in man than in rabbit. The 

 biceps Hes over and inserts with the brachialis m. (21). 



21. Brachialis (b. anticus) m.: Lateral, and cranial middle 

 third of humerus; to radius and ulna w^ith biceps m. (20). 

 Draws antibrachium craniad. The wide inserting tendons of 

 the clavodeltoid m. (12) and pectoralis major and minor mm. 

 (86, 8c) divide this muscle into an anterior and a posterior 

 portion. 



