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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
Boundary | Structure |
---|---|
Floor | Flexor retinaculum and hypothenar muscles |
Roof | Palmar carpal ligament (superficial continuation of flexor retinaculum) |
Medial | Pisiform bone |
Lateral | Hook 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
Last updated on May 12, 2025