[1] It gives off a branch near the axilla, which pierces the fascia and supplies the skin covering the biceps brachii, nearly as far as the elbow.

The nerve then runs down the ulnar side of the arm medial to the brachial artery, pierces the deep fascia with the basilic vein, about the middle of the arm, and divides into a volar and an ulnar branch.

The volar branch (ramus volaris; anterior branch), the larger, passes usually in front of, but occasionally behind, the vena mediana cubiti (median basilic vein).

The ulnar branch (ramus ulnaris; posterior branch) passes obliquely downward on the medial side of the basilic vein, in front of the medial epicondyle of the humerus, to the back of the forearm, and descends on its ulnar side as far as the wrist, distributing filaments to the skin.

This article incorporates text in the public domain from page 937 of the 20th edition of Gray's Anatomy (1918)