Anatomic Investigation of the Deep Posterior Compartment of the Leg

The purpose of this study is to critically investigate the anatomy of the deep posterior compartment of the leg. Specifically, the relationship of the deep posterior compartment to the superficial posterior compartment and their insertion onto the posteromedial border of the tibia are assessed. Cross-sectioning of 10 fresh-frozen cadaver legs was performed at 2-cm increments. The inferior surface of each section was photographed. The photographs were visually analyzed, and the fascial separation between the posterior compartments along with their relationship to the posteromedial border of the tibia were recorded for each specimen. Magnetic resonance images in the axial plane of 10 healthy, normal volunteers’ lower extremities at 2-cm increments were obtained and analyzed. All specimens and images demonstrated that the medial fascial attachment of the deep posterior compartment was along the posteromedial aspect of the tibia in the proximal third of the leg and was not superficially accessible. In the proximal third of the leg, the superficial posterior compartment fascial attachment overlapped the deep posterior compartment by inserting medial and anterior to the deep posterior compartment fascial attachment. In the middle and distal thirds of the leg, the medial fascial attachment of the deep posterior compartment shifted medially and anteriorly, making the deep posterior compartment superficially accessible. The surgeon must appreciate the change in the anatomic relationships along the medial side of the leg while performing double-incision four-compartment fasciotomy release to obtain a complete release of the muscular portion of the deep posterior compartment.