Ulnar Nerve Guyon's Canal — FRCA Primary MCQ

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ModerateAnatomyUlnar Nerve Guyon's CanalFRCA Primary

At the distal wrist crease, the main trunk of the ulnar nerve passes superficial to the flexor retinaculum as it enters the hand. Through which anatomical passage does it travel?

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Correct answer: B — Guyon's canal (ulnar canal)

The correct answer is **A, Guyon's canal**. The main trunk of the ulnar nerve enters the hand at the distal wrist crease through Guyon's canal, superficial to the flexor retinaculum and adjacent to the pisiform. It subsequently divides into superficial sensory and deep motor branches. The carpal tunnel contains the median nerve and flexor tendons, whereas the flexor carpi radialis tendon occupies a separate tunnel. The cubital tunnel is an ulnar-nerve passage at the elbow, not the wrist. The anatomical snuffbox is a dorsolateral wrist depression containing the radial artery and crossed superficially by branches of the radial nerve; it is not the route taken by the ulnar nerve.

Reference: Lleva JMC, Munakomi S, Sun CE, Chang K-V. Ulnar Neuropathy, Anatomy excerpt. StatPearls Publishing, updated 13 December 2025. https://pubmed.ncbi.nlm.nih.gov/30480959/