Relevant Anatomy for Measuring Forearm Compartment Pressure The forearm has 3 compartments: Volar compartment: Includes the flexor carpi ulnaris, flexor pollicis longus, flexor digitorum profundus, flexor digitorum superficialis, palmaris longus, and flexor carpi radialis muscles and also the ulnar, superficial radial, and median nerves and the radial, ulnar, and anterior interosseus arteries Dorsal compartment: Includes the extensor pollicis longus, abductor pollicis longus, extensor digitorum, extensor digiti minimi, and the extensor carpi ulnaris muscles and also the posterior interosseus nerve and posterior interosseus artery Mobile wad compartment: Includes the brachioradialis, the extensor carpi radialis brevis, and the extensor carpi radialis longus muscles The volar compartment is most commonly affected by compartment syndrome.