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Guyon's Canal

Guyon’s canal is the ulnar nerve and artery passage at the wrist between pisiform and hamate.

RegionUpper Limb
System-

Guyon’s canal is a narrow, fibro-osseous tunnel located on the anteromedial aspect of the wrist. It serves as a passageway for the ulnar nerve and ulnar artery as they enter the hand. This canal is clinically significant due to its association with ulnar nerve compression syndromes

Boundaries

BoundaryStructure
FloorFlexor retinaculum and hypothenar muscles
RoofPalmar carpal ligament (superficial continuation of flexor retinaculum)
MedialPisiform bone
LateralHook of the hamate

Contents

  • Ulnar nerve (splits into superficial and deep branches within or just distal to the canal)
  • Ulnar artery (accompanies the nerve, also divides into superficial and deep branches)

Zones of Compression

Zone Structures Affected Symptoms
Zone 1 Ulnar nerve before branching Motor + sensory loss (hypothenar, interossei, ulnar digits)
Zone 2 Deep branch of ulnar nerve Motor loss only (intrinsic hand muscles)
Zone 3 Superficial branch of ulnar nerve Sensory loss only (ulnar side of ring and little fingers)

Relations

  • Proximal to: Ulnar nerve and artery in the forearm
  • Distal to: Superficial palmar arch, digital branches, and motor innervation of intrinsic hand muscles

Function / Significance

  • Provides a protected route for ulnar neurovascular structures into the palm
  • Divides ulnar nerve into motor and sensory branches

Clinical Significance

  • Guyon’s Canal Syndrome: Ulnar nerve compression due to ganglion cysts, repetitive pressure (e.g., cycling), fractures of the pisiform or hamate
    • Motor symptoms: Weak grip, clawing of 4th/5th fingers
    • Sensory symptoms: Numbness/tingling of ulnar 1.5 digits
  • Handlebar Palsy: Common in cyclists due to prolonged pressure on hypothenar region
  • Distinguishing from Cubital Tunnel Syndrome: Guyon’s canal affects hand only; no forearm muscle involvement

Comparative Anatomy

Guyon’s canal is most prominent in humans due to the increased use of tools and fine motor control. Other species with grasping limbs may have a similar passage but typically without the same clinical relevance.

Published on May 12, 2025
Last updated on May 12, 2025
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