The ulnar nerve is compressed in or near the ulnar tunnel at the wrist due to various causes, leading to motor and sensory dysfunction. Also known as Guyon's canal syndrome.

bubble_chart Diagnosis

1. When compressed at the pisiform bone level, both the deep and superficial branches of the ulnar nerve may be affected, causing numbness, pain, and weakness on the ulnar side of the hand, decreased sensation in the ulnar palm and the ring and little fingers, claw-like deformity of the hand and foot, and atrophy of the interosseous muscles and hypothenar muscles. If compressed distal to the hook of the hamate, only the deep branch is affected, leading to interosseous muscle paralysis without sensory impairment.

2. Compression or light tapping at the ulnar tunnel in the wrist may cause radiating numbness and pain to the ring and little fingers (positive Tinel's sign).

bubble_chart Treatment Measures

Early treatment may involve physical therapy, local immobilization, injections of acetic acid and prednisolone, or addressing the underlying disease cause. If symptoms are severe, surgery should be performed as soon as possible to explore the cause of nerve compression and relieve the pressure on the nerves.