210 ELEMENTS OF MAMMALIAN ANATOMY. 
aspect of the biceps to the cranial aspect of the forearm, 
where it becomes subcutaneous. It supplies the biceps and 
coracoid muscles and the skin of the forearm. The internal 
cutaneous arises from the first thoracic and passes along the 
ventral side of the arm, becoming subcutaneous just proxi- 
mad of the elbow, where it is distributed to the skin of the 
arm and forearm on the caudal and ventral aspects. 
The musculospiral arises from the seventh and eighth 
cervical and first thoracic nerves. It is the largest com- 
ponent of the brachial plexus. It winds obliquely around 
the humerus to the cranial aspect, where it divides into two 
branches, the radial and the posterior interosseous. The 
radial nerve is the smaller and becomes subcutaneous near 
the elbow, and passes along the radial region. The pos- 
terior interosseous proceeds along the dorsal aspect of the 
forearm to the wrist, where it divides into branches supply- 
ing the digits. 
The median nerve arises from the seventh and eighth 
cervical and first thoracic. It follows the course of the 
brachial artery, passing through the supracondylar foramen 
to the elbow, where it passes beneath the pronator teres to 
the carpal region, and supplies the first, second, and third 
digits. It also supplies the pronator teres and flexor 
muscles of the forearm. 
The ulnar nerve (Fig. 105) is derived from the eighth 
cervical and first thoracic. It courses with the brachial 
artery to the middle of the humerus, where it turns caudad 
to pass between the olecranon process and internal condyle 
of the humerus. It is here subcutaneous and furnishes the 
sensation experienced when one strikes what is popularly 
called his “ funny bone,” but what is really the ulnar nerve. 
It then passes down the ulnar side of the forearm, supply- 
ing some of the flexor muscles, and finally divides to supply 
the fourth and fifth digits. The ventral branches of the 
