Compartments Deep to the Extensor Retinaculum

Anatomical Structure and Location

The extensor retinaculum is a fibrous band located in the dorsal aspect of the wrist, responsible for stabilizing the tendons of the extensor muscles. Beneath the retinaculum, six distinct compartments house various tendons, enabling efficient hand and wrist movements.

Extensor Compartments

First Compartment

Contains the tendons of the abductor pollicis longus and extensor pollicis brevis, essential for thumb movements.

Second Compartment

Encloses the extensor carpi radialis longus and brevis tendons, aiding in wrist extension and abduction.

Third Compartment

Houses the extensor pollicis longus tendon, facilitating thumb extension at the interphalangeal joint.

Fourth Compartment

Contains the extensor digitorum and extensor indicis tendons, which are crucial for finger extension.

Fifth Compartment

Includes the extensor digiti minimi tendon, allowing extension of the little finger.

Sixth Compartment

Hosts the extensor carpi ulnaris tendon, contributing to wrist extension and adduction.

Clinical Relevance

Understanding these compartments is essential for diagnosing and managing conditions such as tenosynovitis, extensor tendon injuries, and post-traumatic wrist disorders.