FRONT OF THE ARM. 107 



which is occasionally present, and regains its usual position. 

 This anomaly is analogous to the ordinary distribution of 

 the vessel in some carnivorous animals, in which it passes 

 through a foramen in the humerus, a short distance above 

 the inner condyle. 



The brachial artery has three branches. 



Superior and Inferior Profunda, 

 Anastomotica Magna. 



The superior profunda is given off close below the tendon of the 

 latissimus dorsi ; it passes under, and winds around the humerus, to 

 reappear in the muscular interspace on the outer side of the brachialis 

 anticus, where it inosculates with the radial recurrent artery. The 

 profunda artery sends a branch down the posterior aspect of the hu- 

 merus, to the articulation, and this inosculates with the recurrent 

 branch of the posterior interosseous artery. 



The inferior profunda is a small branch given off about the middle 

 of the arm; it passes downward, penetrates behind the inner condyle, 

 and inosculates with the posterior ulnar recurrent. This artery often 

 arises from the preceding, or is altogether wanting. 



The anastomotica magna is given off upon the inside of the arm just 

 above the elbow; it runs transversely inward through the inter-mus- 

 cular septum to the hollow between the olecranon and the inner con- 

 dyle, where it inosculates with the inferior profunda and the posterior 

 ulnar recurrent branch. One of its muscular offsets forms an arch 

 across the back of the humerus with a branch of the superior pro- 

 funda. 



If the various branches into which the brachial plexus 

 of nerves divides, and which are distributed to the arm 

 and forearm, have been carefully followed out, as far as 

 the elbow, in connection with the previous dissection, they 

 will be found to be seven in number, viz : 



External Cutaneous, Circumflex, 



Internal Cutaneous, Musculo-spiral, 



Lesser Internal Cutaneous, Median, 

 Ulnar. 



The EXTERNAL, or MUSCULO-CUTANEOUS, or PERFORANS 

 CASSERII NERVE, arises in common with the external head 

 of the median nerve; it supplies the coraco-brachialis, 

 which it pierces (hence its name of perfor ans), and the 

 biceps and brachialis anticus, and passes between these two 

 muscles to appear on the outer side of the elbow, where it 

 divides into two branches, both supplying the integument, 

 the external down to the back of the hand, and the internal 

 as far as the wrist anteriorly. 



