Carpal tunnel syndrome

Case contributed by Dr Subash Thapa


Burning pain, numbness and paraesthasia over the radial aspect of the right hand more at night and exacerbated by prolonged work.

Patient Data

Age: 35 years
Gender: Female

There is thickening of the median nerve with cross section area > 10mm2 at the proximal carpal tunnel (scaphoid-pisiform level) with loss of normal fascicular architecture.

On dynamic examination the median nerve is sliding superficially to the flexor digitorum superficalis tendon.

Case Discussion

Carpal tunnel is formed posteriorly by the carpal bones and extrinsic ligaments, and anteriorly by the flexor retinaculum or transverse carpal ligament, a thin fibrous band which inserts into the scaphoid and trapezium on the radial aspect and into the pisiform and hook of hamate on the ulnar side.

The median nerve runs superficial to the FDS (flexor digitorum superficialis) tendon for the second finger and medial to the FPL (flexor pollicis longus) tendon.

USG finding in carpal tunnel syndrome:

Median nerve typically swollen at the proximal carpal tunnel and flattened as it passes beneath the flexor retinaculum and at the distal extent of the tunnel regardless of the cause of the compression.

An abrupt change in the caliber of the nerve at the proximal carpal tunnel is referred to as the ‘notch sign’.

An increased cross section area of more than 10mm2 at the proximal carpal tunnel (scaphoid-pisiform level ) is generally accepted to be diagnostic of carpal tunnel syndrome.

PlayAdd to Share

Case information

rID: 40095
Published: 7th Oct 2015
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.