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Ulnar tunnel syndrome

Ulnar tunnel syndrome refers to compression of the ulnar nerve as it passes through Guyon’s canal between the pisiform and the hamate. This is common in cyclists and is due to pressure of the hands against the handlebars.
Synonym(s): Handlebar palsy; Guyon's canal syndrome
Type 1: Combined sensory and motor deficit
Type 2: Motor deficit only
Type 3: Sensory deficit only

Guyon's canal is located in the base of the hand on the ulnar side.

The borders of Guyon's canal are:

  • Pisiform (medially)
  • Hook of the hamate (laterally)
  • Volar carpal ligament/pisohamate ligament (roof)
  • Transverse retinacular ligament (floor)

Symptoms can be motor (weakness of finger abduction), sensory (numbness or tingling in the ulnar 1 1/2 digits), or mixed, depending on the branch of the nerve affected. 

Ulnar tunnel syndrome
Ulnar tunnel syndrome

The clinical diagnosis may be confirmed by nerve conduction studies.
Treatment includes the use of cycling gloves or handlebar padding and changes to the position of the hands when cycling, anti-inflammatory medication, or, in severe or chronic cases, surgical decompression.