The Extensor Tendon Compartments of the Wrist

Written by Oliver Jones

Last updated December 21, 2022 • 19 Revisions •

The extensor tendon compartments of the wrist are six tunnels which transmit the long extensor tendons from the forearm into the hand

They are located on the posterior aspect of the wrist. Each tunnel is lined internally by a synovial sheath and separated from one another by fibrous septa.

In this article, we shall look at the anatomy of the extensor compartments of the wrist – their location, contents and clinical correlations.

Fig 1
The extensor tendon compartments of the wrist.

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Compartment 1

The first extensor compartment is located on the lateral (radial) aspect of the wrist. It transmits two tendons:

  • Extensor pollicis brevis
  • Abductor pollicis longus

These tendons form the lateral border of the anatomical snuffbox.

De Quervain’s Tenosynovitis

De Quervain’s tenosynovitis is inflammation of the tendons within the first extensor compartment of the wrist, resulting in wrist pain and swelling. It is most common in women between the ages of 30-50, especially in those with occupations or hobbies involving repetitive movements of the wrist.

Patients with De Quervain’s tenosynovitis will often complain of pain near the base of the thumb with an associated swelling (secondary to thickening of the tendon sheath). Movements involving grasping or pinching are particularly painful and difficult.

Conservative management of De Quervain’s tenosynovitis involves lifestyle advice (avoiding repetitive actions) and a wrist splint. Steroid injections will reduce swelling and relieve pain in most cases, and can be repeated several times if a good response is observed.

For those failing to respond to conservative management, surgical decompression of the extensor compartment can be performed under local or general anaesthetic.

Compartment 2

The second extensor compartment contains the tendons of the extensor carpi radialis longus and extensor carpi radialis brevis.

This compartment is separated from compartment 3 by Lister’s tubercle – a bony prominence of the distal aspect of the radius.

Compartment 3

Compartment three conducts the extensor pollicis longus tendon – this forms the medial border of the anatomical snuffbox.

Fig 2
The posterior compartment of the forearm and

Compartment 4

The 4th extensor compartment of the wrist transmits the tendons of the extensor digitorum and extensor indicis.

Compartment 5

Compartment five contains the extensor digiti minimi tendon, which travels into the little finger.

Compartment 6

The sixth compartment is the located on the medial (ulnar) aspect of the wrist. It conducts the tendon of the extensor carpi ulnaris.

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