Rare Bilateral Variations in the Origin of the Plantaris Muscle: A Case Report and Literature Review

The plantaris muscle is spindle-shaped in the posterior compartment of the leg. It is distinguished for its small muscle belly and an exceptionally long tendon. It presents with great variability in its origin and insertion when present. This case report presents a novel bilateral variation in the origin of the plantaris muscle in a male cadaver. In addition, it studies the clinical implications behind this novel variation. A 75-year-old male cadaver was dissected following the guidelines of the 16th edition of Grant's Dissector in the Anatomy Lab at the American University of Beirut. This case report showcased that the plantaris muscle in the left lower limb of the male cadaver comprises two separate plantaris muscle bellies that have distinct origins, and their tendons insert distally at the Achilles tendon. While in the right lower limb, two plantaris muscle bellies emerged from the same origin, i.e., the lateral supracondylar line of the femur, and their tendons insert distally at the Achilles tendon. The presence of such an anatomical variation in the plantaris muscle can have significant clinical outcomes that could possibly help physicians with diagnosis and treatment.