A 62-year-old woman presents to the physician complaining of bilateral wrist pain and weakness which has been gradually progressing over the past 2 months. She works as a concert pianist. Physical examination reveals positive Phalen and Tinel maneuvers. Manual compression of the carpal tunnel also reproduces the symptoms. Wasting of the thenar eminence is noted bilaterally. Nerve conduction testing confirms compression of the median nerve bilaterally. She elects surgical intervention to relieve her symptoms.
Which of the following structures is targeted by the planned surgical intervention?
- A) Annular ligament of the radius
- B) Extensor retinaculum
- C) Flexor retinaculum
- D) Interosseus membrane of the forearm
- E) Ulnar collateral ligament of the thumb
C) Flexor retinaculum
Carpal tunnel syndrome results from compression of the median nerve as it travels through the carpal tunnel. It results in pain and paresthesias, and sometimes weakness, in the distribution of the median nerve (the first three digits and the lateral half of the fourth digit). The flexor retinaculum covers the carpal bones and encloses the median nerve in the carpal tunnel. Carpal tunnel release surgery generally includes an incision into this ligament.
Answer A: Annular ligament of the radius, is incorrect. The annular ligament encircles the head of the radius and stabilizes it in contact with the radial notch of the ulna.
Answer B: Extensor retinaculum, is incorrect. The extensor retinaculum is the anatomical term for the thickened part of the antebrachial fascia that holds the tendons of the extensor muscles on the dorsal forearm.
Answer D: Interosseus membrane of the forearm, is incorrect. The interosseus membrane of the forearm is a dense fibrous sheet of connective tissue between the radius and ulna.
Answer E: Ulnar collateral ligament, is incorrect. The ulnar collateral ligament of the thumb of one of two main supporting ligaments traversing the metacarpophalangeal joint of the thumb (the other is the radial collateral ligament). These ligaments provide static stability to the thumb. The ulnar collateral ligament is most typically injured as a result of forced abduction of the thumb.
Key Learning Point
Carpal tunnel syndrome results from compression of the median nerve as it travels through the carpal tunnel under the flexor retinaculum. The flexor retinaculumcan be surgically released to treat carpal tunnel syndrome.