Forearm Compartment Syndrome

Excerpt

Compartment syndrome is a condition in which increased tissue pressure within a limited space compromises the circulation and function of the contents of that space. This happens when pressure is elevated over a certain level for some time sufficient to reduce capillary perfusion. The inadequate tissue perfusion then leads to inadequate tissue oxygenation to the nerves as well as muscles within the affected compartment.

Compartment syndrome was first described in 1881 by Richard von Volkmann, a German surgeon, who first described the Volkmann contracture in a publication called 'Non-infective ischaemic conditions of various fascial compartments in the extremities.' He believed at the time that the contracture was not due to nerve damage but rather to ischemia.

The anatomy of the forearm is very complex. The ulna and the radius represent the bony structure. There are 3 compartments of muscles.

The three compartments are:

1. The anterior compartment contains the hand and wrist flexors, which are divided into a superficial group (flexor carpi radialis FCR, palmaris longus PL, flexor carpi ulnaris FCU, pronator teres PT, flexor digitorum superficialis FDS) and a deep group (flexor digitorum profundus FDP, flexor policis longus FPL, pronator quadratus PQ). The muscles are largely involved with flexion of the wrist and fingers and pronation. The superficial muscles have their origin on the common flexor tendon on the medial epicondyle of the humerus. The ulnar nerve and artery are also contained within this compartment. The flexor digitorum superficialis lies in between the other four muscles of the superficial group and the three muscles of the deep group. This is why, in some literature, it is classified as the intermediate group.

2. The posterior compartment contains 9 muscles responsible for extension of the wrist and digits and supination of the forearm. It is separated from the anterior compartment by the interosseous membrane between the radius and ulna. It is divided into 3 groups: superficial group (extensor carpi ulnaris ECU, anconeus), intermediate group (extensor digitorum, extensor digiti minimi), and deep group (abductor policis longus APL, extensor policis longus EPL, extensor policis brevis EPB, extensor indicis, supinator). Extensor tendons pass through the extensor retinaculum at the wrist joint in 6 compartments. The supinator and the anconeus are the two muscles in the posterior compartment of the forearm that does not pass through the wrist extensor compartments.

3. The lateral compartment contains the mobile wad of Henry, represented by the brachioradialis, extensor carpi radialis longus ECRL, and extensor carpi radialis brevis ECRB.

The nerves that supply the forearm are the radial nerve, the median nerve, and the ulnar nerve, with their sensory and motor branches.

The vascular supply is provided by the radial artery and the ulnar artery and their anastomotic vessels.