Durkan Test or as it called the carpal compression test is used to test for Carpal Tunnel SyndromeCTS where the median nerve is compressed in the carpal tunnel of the wrist. It was first described by JA Durkan in 1991.
The median nerve innervates the skin of the palmar (volar) side of the index finger, thumb, middle finger, and half the ring finger, and the nail bed.
The flexor retinaculum (transverse carpal ligament) spans the region between the pisiform, hamate, scaphoid, and trapezium, transforming the carpal arch into a tunnel, through which the median nerve and some of the tendons of the hand pass.
The proximal attachment of the retinaculum is at the tubercle of the scaphoid and the pisiform. The hook of the hamate and the tubercle of the trapezium serve as its distal attachment.
The retinaculum also:
serves as an attachment site for the thenar and hypothenar muscles;
helps maintain the transverse carpal arch;
acts as a restraint against bowstringing of the extrinsic flexor tendons,
protects the median nerve.
The structures that pass deep to the flexor retinaculum include:
flexor digitorum superficialis (FDS),
flexor digitorum profundus (FDP),
flexor pollicis longus (FPL),
flexor carpi radialis (FCR).
The structures that pass superficial to the flexor retinaculum include:
the ulnar nerve and artery,
the tendon of the palmaris longus.
the sensory branch (anterior (palmar) branch) of the median nerve.
The carpal tunnel serves as a channel for the median nerve and nine flexor tendons. The floor of the tunnel is formed by the anterior (palmar) radiocarpal ligament and the anterior(palmar) ligament complex. As mentioned previously, the roof of the tunnel is formed by the flexor retinaculum. The radial and ulnar are formed by carpal bones (hook of hamate and trapezium , respectively). The median nerve divides into a motor branch and distal sensory branches within the tunnel.
Carpal Tunnel Syndrome:
This condition occurs most commonly in women in the 30–60-year age group.