Brief Outline of Ulnar Tunnel Syndrome
One of three major nerves responsible for motor function and sensation in the hand, the ulnar nerve runs along the inside of the forearm, reaching down to the heel of the hand. In the hand, the ulnar nerve radiates across the palm and into the little finger and ring finger. Pressure on the ulnar nerve can result in pain, loss of sensation and muscle weakness in the hand.
Anatomy and physiology
The humerus of the upper arm has three bony points, frequently associated with repetitive strain injuries. Two of these bony points are involved in ulnar tunnel syndrome, the olecranon and the medial epicondyle in the elbow. The space between these bony protrusions is known as the ulnar tunnel. The ulnar nerve, which acts on the muscle that pulls the thumb toward the palm of the hand, also controls small intrinsic muscles of the hand. It passes through the cubital or ulnar tunnel at the elbow, running down the forearm and into the hand. It is one of the three major nerves in the arm, the others being the radial and median nerves.
Cause of Ulnar Tunnel Syndrome
Overuse of muscles and tendons of the forearm, especially in golf, and sports involving throwing. Abnormal growth in the wrist, such as cyst. Sudden trauma to the ulnar nerve within the ulnar tunnel.
Sign and symptoms
Weakness and increasing numbness on the little finger side of the hand. Difficulty grasping and holding objects. Tingling along the outer forearm, especially when the elbow is bent.