Carpal tunnel syndrome - ultrasound

Case contributed by A.Prof Frank Gaillard

Findings suggestive of carpal tunnel syndrome on the right with distortion and flattening of the median nerve.

  • enlargement of the nerve proximal to the flexor retinaculum (compared to contralateral asymptomatic side)
  • distal flattening of the nerve (seen on transverse image)
  • palmar bowing of the flexor retinaculum (>2 mm beyond a line connecting the pisiform and the scaphoid)

Case Discussion


Enlargement of the nerve distal to the flexor retinaculum seems to be the most sensitive and specific criterion, but what cut-off value for pathological size remains debated; normal cross-sectional area is given at 9-11 mm², but the range of sizes deemed pathological is wide. 

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Case information

rID: 8164
Published: 16th Jan 2010
Last edited: 5th Aug 2018
Inclusion in quiz mode: Included

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