AN ANATOMICAL VARIATION OF THE PERONEUS QUARTUS MUSCLE: A CASE STUDY

Abstract

The peroneus quartus (PQ), an extraneous assessory muscle of the ankle, is found in the lateral compartment of the leg. It is the most frequent source of genesis and its insertion is along the peroneus brevis muscle into the calcaneo retrotrochlear prominence. We noticed a peculiar variation of the muscle that arises from the lateral surface of the fibula in between the two peroneal muscles. A lateral malleolus that was protruding from the skin was crammed with tendons. The muscle was discovered to be attached to the peroneal trochlea. The peroneus quartus is found with a frequency varying from 10 to 21.7% of observed individuals. It is rarely involved in pathologic processes of the foot and ankle. Only a few reports exist in the literature involving peroneus quartus in a “retro malleolar conflict” (lateral ankle stenosis), sometimes in association with longitudinal attrition and tears of the peroneus brevis. The presence of this muscle in individuals can complain of ankle pain with throbbing and tingling sensation along with swelling. It could include the ankle weakness along with ankle instability.1