78 ANATOMY OF THE RABBIT 



the nerves. It is not necessary nor desirable to attempt to find 

 the dorsal and ventral roots of the spinal nerves which form the 

 brachial plexus at this time, for this would entail cutting away 

 portions of the vertebrae, whereas the spinal nerves may be 

 identified easily and more safely by simply tracing them to 

 the point of emergence. 



Method: Clear away the superficial material in the axilla and 

 dissect the tissue away from the ventral surface of each nerve 

 cord with the grooved director and fine-pointed forceps, making 

 the strokes peripherad, and beginning with the cord formed by 

 spinal nerves T.I and C.VIII, for T.I passes from caudad of the 

 first rib to join C.VIII craniad to this landmark. The student 

 should determine definitely through which of the intervertebral 

 foramina each spinal nerve of the brachial plexus emerges. The 

 nerves of the antibrachium and hand are described at this time 

 merely for convenience; the student should dissect out the 

 arteries and nerves of this region at the same time. 



1. Anterior thoracic nerve: C.VII; to proximal end of 

 pectoral muscles, entering with the anterior thoracic artery (2). 

 There are sometimes more than one of these nerves. 



2. Long anterior thoracic n.: Fibers from T. I, C.VIII, 

 and C.VII by two or more nerves; to distal end of the pectorals 

 and latissimus dorsi. (Intercostals, especially the first, also 

 send branches to this region.) 



3. Suprascapular n.: C.VI, chiefly; to medial part of 

 supraspinatus and supraglenoid region, pectoral mm. and prob- 

 ably to the skin on medial surface of arm. This nerve also 

 sends branches over the cranial border of the scapula to the 

 supraspinatus m. 



4. Axillary (circumflex) n.: C.VII, C.VI; to teres minor, 

 subscapularis and deltoid muscles, other structures in the region 

 dorsocaudad to the shoulder joint and lateral integument. 

 There is an anterior and a posterior branch, similar to that in man. 



5. Musculocutaneous n.: C.VII principally; to biceps bra- 

 chii, coracobrachiaHs, brachialis anticus mm. and integument of 

 radial side of forearm, very much as in man. It pierces the 



