This document discusses carpal tunnel syndrome, which is the most common entrapment neuropathy. It causes thickening of the synovium and has frequent anatomic variations. The median nerve passes through the carpal tunnel, the narrowest and thickest portion of the forearm. Symptoms occur due to compression of the median nerve in the tunnel. The document outlines the anatomy and variations that can occur in the structures passing through the carpal tunnel.

2.  Most common entrapment neuropathy
 Causes
 Thickening of synovium
 Frequent anatomic variations

3.  Function
 Attachments
 Contents
 Closed compartment
 Site marking
 Deep antebrachial fascia and palmar
aponeurosis
 Anomalous muscle
 Narrowest and thickest portion

5.  Roots
 Sensory
 Motor
 Course in forearm
 Palmar cutaneous branch
 Position in flexion and extension
 Terminal branches
 Origin and penetration of thenar branch

6.  Digital nerves
 Lumbricals
 Ulnar to thenar crease

7.  Palmar arches
 Marking
 Communicating branch
between sensory parts of
median and ulnar nerve
 Deep branch of ulnar nerve

9.  Extreme radial to anterior
 20% anomalous origin
 12.5% multiple motor branches
 56% separate tunnel

10.  Duplication of motor br + thin sensory
branch
 Transligamentous to abductor,
opponens , extraligamentous to flexor
 Accessory sensory br with TCDN arising
proximally

13.  Between ulnar and median nerve in
forearm
 Rarely in distal forearm and palm
 Variations
 Subtypes

14.  Marinacci communication
 Riche Cannieu
 Berretini