| Ulnar canal | |
|---|---|
 Transverse section across the wrist and digits. | |
 Superficial palmar nerves. | |
| Details | |
| Identifiers | |
| Latin | canalis ulnaris |
| TA98 | A03.5.11.202 |
| TA2 | 2552 |
| FMA | 42358 |
| Anatomical terminology | |
Theulnar canal orulnar tunnel(also known asGuyon's canalortunnel) is a semi-rigid longitudinal canal in the wrist that allows passage of theulnar artery andulnar nerve into the hand.[1] (These are named after theulna, the long bone on the little finger side of the arm.) The roof of the canal is made up of the superficialpalmar carpal ligament, while the deeperflexor retinaculum andhypothenar muscles comprise the floor. The space is medially bounded by thepisiform andpisohamate ligament more proximally, and laterally bounded by thehook of the hamate more distally.[2][3] It is approximately 4 cm long, beginning proximally at the transverse carpal ligament and ending at the aponeurotic arch of the hypothenar muscles.[4]
The ulnar tunnel is named after the French surgeonJean Casimir Félix Guyon, who originally described the canal in 1861.[5]
Entrapment of the ulnar nerve at the ulnar canal can result in symptoms of ulnar neuropathy, including numbness or weakness of certain parts of the hand.[6] (See full article onulnar nerve entrapment.) This is known asulnar nerve entrapment orGuyon's canal syndrome. There are four subtypes ofulnar neuropathy at the wrist, of which type II is the most common. Guyon's canal syndrome[7] may be secondary toganglion cyst formation, or compression against abicycle handlebar.
