Ulnar canal

The ulnar canal, also known as Guyon's canal, is a semi-rigid longitudinal space in the wrist that allows passage of the ulnar nerve and ulnar artery into the hand. It is named after the French surgeon Jean Casimir Felix Guyon.

Anatomical illustration of the ulnar nerve and artery in the wrist.

Anatomy

The ulnar canal is located on the medial side of the wrist, adjacent to the carpal bones. It is bordered by the pisiform bone and the hook of hamate. The roof of the canal is formed by the palmar carpal ligament and the palmaris brevis muscle, while the floor is formed by the transverse carpal ligament and the flexor retinaculum.

Diagram of the carpal tunnel, with the ulnar canal located medially.

Contents

The ulnar canal contains the ulnar nerve and the ulnar artery. The ulnar nerve divides into a superficial branch, which supplies the palmaris brevis and the skin of the medial one and a half fingers, and a deep branch, which innervates the hypothenar muscles, the interossei, the third and fourth lumbricals, and the adductor pollicis.

Clinical Significance

Compression of the ulnar nerve in the ulnar canal can lead to a condition known as ulnar tunnel syndrome. Symptoms of this condition include numbness and tingling in the ring and little fingers, weakness of the intrinsic muscles of the hand, and a loss of grip strength. Causes of compression can include ganglion cysts, lipomas, or repetitive trauma.

Diagnosis and Treatment

Diagnosis of ulnar tunnel syndrome is typically made through clinical examination and may be confirmed with nerve conduction studies. Treatment options include rest, splinting, and in some cases, surgical decompression of the ulnar canal.

Related Pages

• Carpal tunnel
• Ulnar nerve
• Wrist anatomy

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