ANATOMICAL VARIATIONS OF MEDIAN NERVE IN CARPAL TUNNEL
INTRODUCTION
Most common entrapment neuropathy Causes Thickening of synovium Frequent anatomic variations
Surgical anatomy of carpal tunnel
Function Attachments Contents Closed compartment Site marking Deep antebrachial fascia and palmar
aponeurosis Anomalous muscle Narrowest and thickest portion
Median nerve
Roots Sensory Motor Course in forearm Palmar cutaneous branch Position in flexion and extension Terminal branches Origin and penetration of thenar
branch
Digital nerves Lumbricals Ulnar to thenar crease
Distal end of carpal tunnel
Palmar arches Marking Communicating branch
between sensory parts of median and ulnar nerve
Deep branch of ulnar nerve
Variations
Recurrent motor branch
Extreme radial to anterior 20% anomalous origin 12.5% multiple motor branches 56% separate tunnel
Group 2 variations
Duplication of motor br + thin sensory branch
Transligamentous to abductor, opponens , extraligamentous to flexor
Accessory sensory br with TCDN arising proximally
Median nerve within carpal tunnel
Variations of TCDN
Martin Gruber anastomosis
Between ulnar and median nerve in forearm
Rarely in distal forearm and palm Variations Subtypes
Marinacci communication Riche Cannieu Berretini