Anatomy of the Upper Limb | Which nerve is injured? | Med School Bootcamp

Added: 2026-05-16

[00:00:00]A 10-year-old boy falls on an outstretched hand and sustains a fracture at the medial epicondyle of the humerus. Which nerve is most likely injured? Pause the video and lock in your answer in the comments. Let's break down the anatomy. You're looking at a right anterior view of the arm. Here's the biceps brachii, the coracobrachialis, and the triceps brachii. Running between them are the median nerve, the musculocutaneous nerve, and the medial cutaneous nerve of the arm. The arrow's pointing to a nerve that disappears posterior to the medial epicondyle. This is the ulnar nerve, a terminal branch of the medial cord of the brachial plexus, carrying fibers from C8 to T1. It passes posterior to the medial epicondyle, then enters the forearm to eventually go and innervate most of the intrinsic muscles of the hand, as well as the skin above the ring finger and the pinky finger. Now, that medial epicondyle fracture damages the ulnar nerve where it's most vulnerable, producing the ulnar claw hand. The ring and the little fingers hyperextend at the metacarpophalangeal joints and flex at the interphalangeal joints because those lumbricals that go to those digits are paralyzed. Want more cadaveric materials like this for boards? Head to bootcamp.com.