A 36-year-old woman is evaluated for several months of tingling and numbness of the right hand and fingers that has progressed to dull, aching pain. The symptoms initially were intermittent but have become persistent, with the pain worsening overnight. The patient works as an office secretary and has had difficulty typing and holding the phone due to hand weakness. On examination, she has weakness of thumb opposition and atrophy of the thenar eminence. The patient attempted treatment with conservative measures but had no significant improvement and has now been referred for surgery. During surgery, incision of which of the following structures is most likely to improve this patient's symptoms?

Question

A 36-year-old woman is evaluated for several months of tingling and numbness of the right hand and fingers that has progressed to dull, aching pain.  The symptoms initially were intermittent but have become persistent, with the pain worsening overnight.  The patient works as an office secretary and has had difficulty typing and holding the phone due to hand weakness.  On examination, she has weakness of thumb opposition and atrophy of the thenar eminence.  The patient attempted treatment with conservative measures but had no significant improvement and has now been referred for surgery.  During surgery, incision of which of the following structures is most likely to improve this patient's symptoms?

Quizplus · Accepted Answer

11ec160b_35a1_7dec_9249_2f588282ae24_MD0001_00 This patient has right hand pain and numbness, thenar atrophy, and weakness of thumb opposition characteristic of carpal tunnel syndrome (CTS). The carpal tunnel is an anatomic space in the wrist between the carpal bones and the transverse carpal ligament (flexor retinaculum). The median nerve and 9 tendons (eg, flexor digitorum superficialis and profundus, flexor pollicis longus) pass through the carpal tunnel to enter the hand. CTS occurs when increased pressure within the carpal tunnel (eg, compression, inflammation) causes median nerve damage. Often, CTS can be managed successfully with nonsurgical treatments (eg, wrist splint, glucocorticoid injection). However, patients with significant impairment and evidence of median nerve injury on electromyography are often treated with surgical decompression. A longitudinal incision through the transverse carpal ligament decreases the pressure on the median nerve, improving patients' symptoms. (Choice A) The fibrous flexor sheaths are thick tunnels on the palmar surface of the fingers that act like pulleys to allow the flexor digitorum profundus tendons to flex the fingers at the interphalangeal joints. Swelling of the tendon and/or fibrous sheath can result in painful catching or locking of the affected finger during flexion (ie, trigger finger). (Choice B) The flexor carpi ulnaris aponeurosis spans from the olecranon to the medial epicondyle and forms the roof of the cubital tunnel. The ulnar nerve runs through this space, and compression here can cause sensory loss over the ulnar aspect of the hand. (Choice C) The palmar aponeurosis (palmar fascia) spans from the flexor retinaculum at the wrist and is continuous with the fibrous flexor sheaths of the digits. Fibrosis of the palmar aponeurosis can result in Dupuytren contracture, which is a progressive disorder characterized by nodular lesions in the palm with restricted finger motion. (Choice D) The synovial sheaths of the flexor digitorum superficialis and profundus tendons pass through the carpal tunnel around the flexor tendons. However, incision of synovial sheaths would not relieve the pressure on the median nerve in CTS. Educational objective: The carpal tunnel is formed by the carpal bones and the transverse carpal ligament (flexor retinaculum). Carpal tunnel syndrome results from compression of the median nerve as it passes through the carpal tunnel with 9 flexor tendons. Longitudinal incision of the transverse carpal ligament can decrease pressure within the carpal tunnel, improving patients' symptoms. __________ References: Carpal tunnel syndrome - anatomical and clinical correlations. (http://www.ncbi.nlm.nih.gov/pubmed/24858452)

A 36-Year-Old Woman Is Evaluated for Several Months of Tingling