Musculoskeletal images. Ganglion cyst of Guyon's canal causing ulnar nerve compression

• Published in: Canadian Journal of Surgery Vol. 44; no. 5; pp. 331 - 332
• Main Authors: Elias, D A, Lax, M J, Anastakis, D J
• Format: Journal Article
• Language: English
• Published: Canada CMA Impact, Inc 01.10.2001; Canadian Medical Association
• Subjects: Arms; Cysts - complications; Cysts - diagnostic imaging; Humans; Male; Middle Aged; Nervous system diseases; Radiography; Surgical Images; Ulnar Nerve Compression Syndromes - diagnosis; Ulnar Nerve Compression Syndromes - etiology; Ultrasonography; Wrist - diagnostic imaging
• ISSN: 0008-428X; 1488-2310

Within the forearm the ulnar nerve supplies the flexor digitorum profundus IV and V and the flexor carpi ulnaris. Palmar and dorsal branches supply sensation to the ulnar sides of the palm and dorsum of the hand. The ulnar nerve then enters the wrist, passing through Guyon's canal along with the ulnar artery. The walls of this canal consist of the pisiform medially and the hook of the hamate laterally. The floor is formed by the flexor retinaculum and the roof by the transverse palmar carpal ligament. Within the canal, the ulnar nerve divides into a deep motor branch, which supplies the muscles of the hypothenar eminence, the interossei, lumbricals III and IV, adductor pollicis and one head of flexor pollicis brevis, and a superficial sensory branch, which supplies sensation to the little finger and the ulnar side of the ring finger. Ulnar nerve compression within Guyon's canal proximal to its bifurcation (termed zone 1) will therefore result in both motor and sensory deficits. Compression of the motor branch only (zone 2) or the sensory branch only (zone 3) will cause purely motor or purely sensory symptoms respectively.