Ulnar collateral nerve is
In the arm, the radial nerve is posterior to the brachial aery. Here it gives muscular branches to long and medial heads of triceps brachii. The branch for medial head lies very close to the ulnar nerve and hence is called the ulnar collateral nerve. ReferenceClinicall Anatomy for students, a problem-solving approach, Neeta v Kulkarni, 2nd edition, page no.179
Branch of ulnar nerve
Branch of radial nerve supplying medial head of triceps
Branch of radial nerve supplying long head of biceps
Branch of radial nerve supplying lateral head of triceps
Upper limb