Guyon's canal

Last revised by Yvette Mellam on 5 Oct 2023

Guyon’s canal (also known as ulnar tunnel or canal) is a fibro-osseous tunnel at the anterior aspect of the wrist. It is superficial and slightly proximal to the flexor retinaculum. It is approximately 4 cm in length, spanning from the proximal aspect of the pisiform to the hook of hamate.

  • ulnar nerve: bifurcates within the canal into the deep (more radial) and superficial (more ulnar) branches

  • ulnar artery and ulnar vein

  • veins associated with the ulnar nerve

  • fat

At the level of the hook of hamate, the canal bifurcates into two channels: the first channel contains the superficial ulnar nerve and ulnar artery, and the second channel contains the deep ulnar nerve. These are separated by either the fibrous arch of the flexor digiti minimi brevis, or the muscle itself attaching to the hook of hamate.

The abductor digiti minimi muscle can occasionally have an anomalous presence in Guyon’s canal. It was present in 25% of a sampled population and can cause compression leading to Guyon's canal syndrome 1.

Described and named by Jean Casimir Felix Guyon (1831-1920), a French anatomist and urologist in 1861 5.

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Cases and figures

  • Figure 1: diagram
    Drag here to reorder.