THE PERONEOCALCANEUS INTERNUS MUSCLE - MR-IMAGING FEATURES

OBJECTIVE. The peroneocalcaneus internus muscle is a rare muscle of th e posterior calf that to our knowledge has not been reported in the ra diology literature. The purpose of our study was to describe the norma l anatomy and MR characteristics of this muscle in eight patients in w hom the muscle was identified. CONCLUSION. The peroneocalcaneus intern us muscle is a rare muscle that originates from the inner aspect of th e distal fibula, descends within the tarsal tunnel, and inserts on a s mall tubercle in the calcaneus, just distal to the sustentaculum tall. The muscle may displace the flexor hallucis longus muscle medially an d thus indirectly encroach on the neurovascular bundle.