The tibialis posterior compartment is a more recently described subdivision of the deep posterior compartment. It consists of the tibialis posterior, which has been shown to have its own fascial layer.
Four interconnected compartments of the forearm are recognized, as follows:
Superficial volar (flexor)
Deep volar
Dorsal (extensor) compartment
Compartment containing the mobile wad of Henry
The deep volar compartment contains the flexor digitorum profundus, flexor pollicis longus, and pronator quadratus muscles and tendons. The mobile wad of Henry comprises the brachioradialis, extensor carpi radialis brevis (ECRB), and extensor carpi radialis longus muscles and tendons.
Elevated pressures most commonly affect the volar compartments, but the dorsal and mobile wad compartments may also be involved, alone or in addition to the volar compartments. It is usually difficult to clinically differentiate isolated or combined involvement of the deep and superficial volar compartments.
In the wrist, most of the soft tissues are bound within rigid compartments for example the volar wrist tendons, for the most part, are tightly constrained within the carpal tunnel (thumb and finger long flexor tendons), except for the flexor carpi radialis, flexor carpi ulnaris, and palmaris longus tendons, which are in separate compartments. The dorsal compartments are primarily channels for tendons and are rarely afflicted by compartment syndrome.
The dorsal extensor tendons pass under an extensor retinaculum and are divided into 6 compartments, as follows:
Radial wrist abductor (abductor pollicis longus tendon) and thumb extensor (extensor pollicis brevis tendon) dorsal to the trapezium bone
Radial wrist extensors (extensor carpi radialis longus and ECRB tendons) dorsal and radial to the trapezoid bone
Extensor pollicis longus tendon
Common finger extensors (extensor digitorum communis [EDC] tendon) dorsal to the capitotrapezoid articulation
Extensor digiti minimi tendon to the fifth digit
Ulnar wrist extensor (extensor carpi ulnaris tendon) in a groove adjacent to the ulnar styloid
↑Mrsiç V, Rasic A, Adam VN, Stojcić EG, Smiljanić A (March 2011). "[Acute compartment syndrome of the muscle in intensive care patients]". Acta Med Croatica. 65 (1): 31–9. PMID21568072.
↑Botte MJ, Gelberman RH (August 1998). "Acute compartment syndrome of the forearm". Hand Clin. 14 (3): 391–403. PMID9742419.
↑Gerow G, Matthews B, Jahn W, Gerow R (May 1993). "Compartment syndrome and shin splints of the lower leg". J Manipulative Physiol Ther. 16 (4): 245–52. PMID8340719.