To better understand ulnar neuritis, it helps to understand the anatomy of the elbow joint.

The ulnar nerve provides motor and sensory functions in the arm and hand. This nerve begins in the neck, travels through the armpit, and down the arm to the hand and fingers. It passes through the inner part of the elbow. It is surrounded by a tunnel formed by muscles, ligaments, and bone. The tunnel is known as the cubital tunnel.

The elbow consists of three bones:

• Humerus: the large, long bone in the upper arm
• Radius: one of the long bones in the forearm
• Ulna: one of the long bones in the forearm

These three bones are bonded together by strong bands, called ligaments. The ligaments, muscles and tendons keep the bones of the elbow together during movement.