ANATOMICAL DISSECTION OF THE DEEP POSTERIOR COMPARTMENT AND ITS CORRELATION WITH CLINICAL REPORTS OF CHRONIC COMPARTMENT SYNDROME INVOLVINGTHE DEEP POSTERIOR COMPARTMENT

Patients with clinical presentation of deep posterior chronic compartm ent syndrome (CCS) frequently have symptoms limited to either proximal or distal components of the deep posterior compartment. In this study the posterior aspect of 15 cadaver legs was dissected to document ana tomical separations and delineate boundaries, if any, of the deep post erior compartment and to correlate the findings to these patients. Ori gins of flexor hallucis longus (FHL), flexor digitorum longus (FDL), a nd tibialis posterior (TP), as well as whether TP existed in its own o sseofascial compartment, were noted. Ten specimens had an identifiable distinct layer of tissue separating the deep posterior compartment in to two potentially clinically relevant components. Much of this layer was derived from origins of FDL and its anatomical position in relatio n to the TP muscle. In seven of these cases, FDL had a significant fib ular origin in addition to the well-established tibial origin. This es sentially compartmentalized the distal third of the tibialis posterior as it descends anterior and medial to FDL in the lower one-third of t he leg in five specimens. No cadaver possessed a significant fascial s eptum encasing TP and separating it from other deep posterior muscles. This study confirms the existence of a proximal and distal sub-compar tment of the deep posterior compartment as a variant and supports the most frequent clinical presentation of deep posterior CCS as involving either the distal or proximal deep compartment, rather than the entir e deep posterior compartment. The anatomic arrangement of muscles in t he deep posterior compartment creates sub-compartments, which may expl ain the successful outcomes following a deep compartment release limit ed to symptomatic portion(s) of the deep compartment. (C) 1997 Wiley-L iss, Inc.