All reported cases have occurred in the anterior tibial or rarely peroneal compartments. Case I and V in this series follow this same pattern. Case II and III are unusual in that they are the first recorded cases of this syndrome occuring in the calf of a leg. In Case IV the syndrome was present both in the anterior compartment as well as in the calf. Case III in addition, demonstrated arteriographic evidence of impairment of blood flow preoperatively which was relieved by fasciotomy. It is this author's opinion that this syndrome develops due to obstruction of venous drainage by a rise in pressure in the myofascial compartment with exercise. Perhaps it occurs in athletes because the muscle hypertrophy in these patients in greater than that in the general public and the margin of safety is reduced. It is not necessary to perform complicated or painful investigative studies to make the diagnosis. Kennelly and Blumberg state that "a convincing history is all that is necessary," and the author is in complete agreement with this statement. Fasciotomy gives complete relief and is earnestly recommended both to relieve symptoms and to prevent the catastrophic consequences of muscle necrosis. In fact, in severe cases it is best to advise cessation of physical exercise until the operation can be done in order that this severe complication does not develop.