Date of download: 6/23/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Does This Patient Have Carpal Tunnel Syndrome? JAMA. 2000;283(23): doi: /jama The carpal tunnel consists of the median nerve and 9 flexor tendonssurrounded by the rigid carpal bones and transverse carpal ligament (flexorretinaculum). The distal wrist crease marks the proximal edge of the carpaltunnel. Within the tunnel, the median nerve divides into a motor branch thatinnervates the thenar muscles (opponens, abductor, short flexor) and distalsensory branches that supply the thumb, index, and middle fingers, and theradial half of the ring finger. Because the sensory branches to the radialpalm do not usually pass through the carpal tunnel, palm sensation is preservedin a classic case of carpal tunnel syndrome. Figure Legend:

Date of download: 6/23/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Does This Patient Have Carpal Tunnel Syndrome? JAMA. 2000;283(23): doi: /jama The patient is instructed to raise his/her thumb perpendicular tothe palm as the examiner applies downward pressure on the distal phalanx.This maneuver reliably isolates the strength of the abductor pollicis brevis,which is innervated only by the median nerve. Figure Legend:

Date of download: 6/23/2016 Copyright © 2016 American Medical Association. All rights reserved. From: Does This Patient Have Carpal Tunnel Syndrome? JAMA. 2000;283(23): doi: /jama Figure adapted with permission. Figure Legend: