Repetitive stress injuries
Carpal tunnel syndrome (CTS) is a disorder marked by weakness and pain in the hand and wrist. CTS occurs in the nerves of the hands -- not the muscles, as some people believe. The symptoms of CTS can be incapacitating.
To understand how carpal tunnel syndrome arises, it is important to know the parts of the hand and wrist that are involved.
The Carpal Tunnel. The carpal tunnel is a passageway that forms beneath the strong, broad transverse ligament. This ligament is a bridge that extends across the lower palm and connects the bones of the wrist (carpals) that form an arch below the tunnel.
The Median Nerve and Flexor Tendons. The median nerve and nine flexor tendons pass under the ligament bridge and through the carpal tunnel (similar to a river). They extend from the forearm and up into the hand:
It is not completely known how the process leading to carpal tunnel syndrome actually evolves, and how nerve conduction (the passing of the nerve signal) through the wrist changes. In general, carpal tunnel syndrome develops when the tissues around the median nerve swell and press on the nerve. Early in the disorder, the process is reversible. Over time, however, the insulation on the nerves may wear away, and permanent nerve damage may develop.
The following events have been observed in the hands of people with carpal tunnel syndrome:
The result is pain, numbness, and tingling in the wrist, hand, and fingers. Only the little finger is unaffected by the median nerve.
Atroshi I, Gummesson C, Ornstein E, et al. Carpal tunnel syndrome and keyboard use at work: a population-based study. Arthritis Rheum. 2007;56(11):3620-3625.
Breuer B, Sperber K, Wallenstein S, et al. Clinically significant placebo analgesic response in a pilot trial of botulinum B in patients with hand pain and carpal tunnel syndrome. Pain Med. 2006;7(1):16-24.
Evcik D, Kavuncu V, Cakir T, et al. Laser therapy in the treatment of carpal tunnel syndrome: a randomized controlled trial. Photomed Laser Surg. 2007;25(1): 34-39.
Hoffman DE. Treatment of carpal tunnel syndrome: is there a role for local corticosteroid injection? Neurology. 2006;66(3):459-460.
Hui AC. A randomized controlled trial of surgery vs steroid injection for carpal tunnel syndrome. Neurology. 2005;64(12): 2074-2078.
Piazzini DB, Aprile I, Ferrara PE, et al. A systematic review of conservative treatment of carpal tunnel syndrome. Clin Rehabil. 2007;21(4):299-314.
Pomerance J, Fine I. Outcomes of carpal tunnel surgery with and without supervised postoperative therapy. J Hand Surg [Am]. 2007;32(8): 1159-1163.
Scholten RJ, Mink van der Molen A, Uitdehaag BM, et al. Surgical treatment options for carpal tunnel syndrome. Cochrane Database Syst Rev. 2007;(4):CD003905
Wright PE. Carpal Tunnel, Ulnar Tunnel, and Stenosing Tenosynovitis. In: Canale ST, Beaty JH. (eds.) Canale & Beaty: Campbell's Operative Orthopaedics, 11th ed. Philadelphia, PA: Mosby;2007.
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