After leaving the side of the neck, the ulnar nerve travels through the arm pit and down the arm to the hand and fingers. As it crosses the wrist, the ulnar nerve and ulnar artery run through the tunnel known as Guyon’s canal. This tunnel is formed by two bones–the pisiform and hamate–and the ligament that connects them. After passing through the canal, the ulnar nerve branches out to supply feeling to the little finger and half the ring finger. Branches of this nerve also supply the small muscles in the palm and the muscle that pulls the thumb toward the palm.