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M01.03.007 The Extensor Tendon Compartments of the Wrist
The extensor tendon compartments of the wrist are six distinct tunnels that transmit the long extensor tendons from the forearm into the hand. These compartments are located on the posterior aspect of the wrist, each lined internally by a synovial sheath and separated by fibrous septa.
This article explores the anatomy, location, contents, and clinical correlations of the extensor compartments.
Overview of Extensor Compartments
| Compartment | Location | Contents | Clinical Relevance |
|---|---|---|---|
| 1 | Lateral (radial) aspect | Extensor pollicis brevis, Abductor pollicis longus | De Quervain’s tenosynovitis |
| 2 | Posterior radius | Extensor carpi radialis longus, Extensor carpi radialis brevis | Separated from compartment 3 by Lister’s tubercle |
| 3 | Medial to Lister’s tubercle | Extensor pollicis longus | Forms medial border of the anatomical snuffbox |
| 4 | Central posterior wrist | Extensor digitorum, Extensor indicis | – |
| 5 | Posterior ulna | Extensor digiti minimi | – |
| 6 | Medial (ulnar) aspect | Extensor carpi ulnaris | – |
Detailed Anatomy of Each Compartment
Compartment 1
- Location: Lateral (radial) aspect of the wrist.
- Contents:
- Extensor pollicis brevis
- Abductor pollicis longus
- Clinical Correlation:
- De Quervain’s Tenosynovitis:
- Definition: Inflammation of the tendons within compartment 1.
- Symptoms: Pain and swelling at the base of the thumb, aggravated by grasping or pinching motions.
- Management:
- Conservative: Lifestyle modifications, wrist splints.
- Interventional: Steroid injections or surgical decompression if refractory.
- De Quervain’s Tenosynovitis:
Compartment 2
- Location: Posterior radius, separated from compartment 3 by Lister’s tubercle.
- Contents:
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
Compartment 3
- Location: Medial to Lister’s tubercle.
- Contents:
- Extensor pollicis longus
- Clinical Note: Forms the medial border of the anatomical snuffbox.
Compartment 4
- Location: Central posterior wrist.
- Contents:
- Extensor digitorum
- Extensor indicis
Compartment 5
- Location: Posterior ulna.
- Contents:
- Extensor digiti minimi
Compartment 6
- Location: Medial (ulnar) aspect of the wrist.
- Contents:
- Extensor carpi ulnaris
Points to Remember
- Anatomical Organization: Compartments are numbered sequentially from lateral to medial.
- Synovial Sheaths: Each compartment is internally lined with a synovial sheath to facilitate smooth tendon movement.
- Lister’s Tubercle: A key anatomical landmark separating compartments 2 and 3.
- Anatomical Snuffbox: Compartments 1 and 3 form its lateral and medial borders, respectively.
Bibliography
- Gray’s Anatomy for Students.
- Drake, R.L., Vogl, W., & Mitchell, A.W. (2019). Clinically Oriented Anatomy.
- Netter’s Clinical Anatomy.