Areas - Extensor Tendon Compartments

Question 1

What are the extensor tendon compartments?

Answer 1

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

Question 2

Compartment 1?

Answer 2

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

• Extensor pollicis brevis
• Abductor pollicis brevis

These tendons form the lateral border of the anatomical snuffbox.

Question 3

Clinical relevance - De Quervains Tendosynovitis?

Answer 3

De Quervains Tendosynovitis is inflammation of the tendons within the first extensor compartment of the wrist, resulting in wrist pain and swelling. It is 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 tendosynovitis will often complain of pain near the base of the thumb with an associated swelling (secondary to thickening of the tendon sheath). Movement involving gasping or pinching are particularly painful and difficult.

Conservative management of De Quervain’s tendosynovitis 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.

Question 4

Compartment 2?

Answer 4

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

Question 5

Compartment 3?

Answer 5

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

Question 6

Compartment 4?

Answer 6

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

Question 7

Compartment 5?

Answer 7

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

Question 8

Compartment 6?

Answer 8

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