Ulnar tunnel syndrome

Ulnar tunnel syndrome, also known as Guyon's canal syndrome or Handlebar palsy, is caused by entrapment of the ulnar nerve in the Guyon canal as it passes through the wrist. Symptoms usually begin with a feeling of pins and needles in the ring and little fingers before progressing to a loss of sensation and/or impaired motor function of the intrinsic muscles of the hand which are innervated by the ulnar nerve. Ulnar tunnel syndrome is commonly seen in regular cyclists due to prolonged pressure of the Guyon's canal against bicycle handlebars.