Guyon's canal syndrome

Guyon's canal syndrome, sometimes referred to as 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. Guyon's canal syndrome is commonly seen in regular cyclists due to prolonged pressure of the Guyon canal against bicycle handlebars.

Contents 1 Pathology 1.1 Type I 1.2 Type II 1.3 Type III 2 Treatment 3 See also 4 References 5 Further reading

Pathology

There are 3 types of Guyon's canal syndrome, characterised by the location within the Guyon canal at which the ulnar nerve is compressed:

Type I

Proximal compression in Guyon's canal leads to motor weakness in all of the intrinsic muscles of the hand which are innervated by the ulnar nerve. There is also sensory loss in the territory of the hand served by the ulnar nerve.

Type II

This is the most common type of Guyon's canal syndrome, and is caused by compression of the ulnar nerve at the lower wrist. This results in symptoms associated with Type I (above), however the sensory branch to the dorsal part of the hand and the motor supply to the muscles of the base of the palm are unaffected. Therefore Type II involves an impairment in motor function of the hand, with sensory innervation unaffected.

Type III

This is the least common type of Guyon's canal syndrome, and is caused by compression of the superficial branch of the ulnar nerve at the distal portion of Guyon's canal. Type III results in a loss of sensation from the cutaneous territory of the hand which is served by the ulnar nerve. There is no motor function impairment.

Treatment

Initial line of treatment is with anti-inflammatory drugs or cortisone injections. There have been trials with gloves which help protect the ulnar nerve from compression. The most radical treatment option is surgery to relieve tension in the Volar carpal ligament which forms the roof of Guyon's canal, thereby reducing compression on the ulnar nerve.^[1]

See also

• Jean Casimir Félix Guyon

References

Further reading

• Slane, Josh; Timmerman, Mark; Ploeg, Heidi-Lynn; Thelen, Darryl G. (2011). "The influence of glove and hand position on pressure over the ulnar nerve during cycling". Clinical Biomechanics 26 (6): 642–8. doi:10.1016/j.clinbiomech.2011.03.003. PMID 21458120. 
• Maimaris, C; Zadeh, H G (1990). "Ulnar nerve compression in the cyclist's hand: Two case reports and review of the literature". British Journal of Sports Medicine 24 (4): 245–6. doi:10.1136/bjsm.24.4.245. PMC 1478904. PMID 2097022. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1478904. 
• Rehak, David C. (Summer 2003). "Cyclist's Hands: Overcoming overuse injuries". Hughston Health Alert. Hughston Clinic. http://www.hughston.com/hha/a_15_3_2.htm. 
• "Cycling injuries - handlebar palsy". Sports Injury Bulletin. http://www.sportsinjurybulletin.com/archive/cycling-injuries.html. 
• US patent 6845514, Yao, Joseph, "Protective device for the median and ulnar nerves", issued January 25, 2005 

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