264 



ANATOMY OF THE RABBIT 



Lateral 



the anterior border of the scapula, entering the supraspinatus 

 muscle. 



By dividing the axillary nerves and vessels and the two parts of 

 the serratus anterior muscle, the limb may be removed from the body. 



3. Muscles arising from the pectoral girdle and inserted on the 

 humerus. These muscles act on the humerus through the 

 shoulder-joint, and except for the unimportant difference in 

 origin are similar to those of Group 2. 



The course of the cephalic vein (p. 271) should be traced be- 

 fore separating the muscles 

 of the front of the forearm. 

 Note the supraspinous 

 and infraspinous fasciae, 

 tough sheets of connective 

 tissue covering the muscles 

 lying in the supraspinous 

 and infraspinous fossae of 

 the scapula respectively. 

 (a) .The cleidohumeralis. 

 Origin : Lateral por- 

 tion of the clavicle and 

 the cleidohumeral liga- 

 ment.^ Insertion: An- 

 terior surface of the 

 humerus in its distal 

 third. The muscle is 

 a continuation of the 

 basioclavicularis, but 

 represents the brachial 

 part of the brachioce- 

 phalic muscle, which, in 

 many mammals with 

 reduced clavicle, ex- 

 tends from the mastoid 



portion of the skull to the front of the arm. 

 part is the cleidomastoideus. 



'Regarding this ligament, see p. 200. 



Posterior 



Fig. 102. Transverse section through the 

 distal portion of the arm; semidiagrammatic; 

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

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

 medial heads of the branchialis; 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. 



The cervical 



