MORPHOLOGICAL VARIATIONS OF MUSCLE PLANTARIS: ANATOMICAL AND CLINICAL INSIGHT

Background: Plantaris is large muscle in mammals other than primates. Plantaris muscle has long been a subject of much confusion and speculation Evolutionists have speculated on its phylogenetic significance, as a vestigial organ, while surgeons have removed it ‘useless vestige’ to employ its tendon as a spare part for the surgical repair, example tendon transfer operations and reconstruction and as a graft in reconstruction of ligaments etc. In humans it is reduced greatly in size, power, and function and may even be absent. Aim: With this background the aim of the present work is to study morphology, describe the observed variations of the Plantaris muscle, and to discuss the functional significance of Plantaris muscle. Methodology: For the present work 84 limbs available in the department of Anatomy were dissected. The posterior aspect of the knee was dissected using standard surgical equipment and dissection techniques. The Plantaris muscle was isolated and length of fleshy belly and tendon were measured. Any variations in origin, insertion and size were recorded. Result: Mean length of fleshy belly of the Plantaris muscle was 8.39 cm on right side and 8.16 cm on left side. In present study Plantaris muscle was absent 6.66% on right side of the leg; while 12.82 % on left side. In present study variation in insertion of the Plantaris were observed like insertion along medial margin of tendocalcaneus on to calcaneus, in front of tendocalcaneus on to calcaneus, fused to tendocalcaneus and insertion of the Plantaris on deep fascia of leg at the level of ankle. Other variations noted were two bellies of the Plantaris one from lateral supracondylar ridge and other from deep surface of Gastrocnemius, two heads of Plantaris: Both bellies were fused in the lower part producing bipennate arrangement, thin & thick belly of the Plantaris muscle. Variations were also observed in relation to origin that Plantaris muscle originating from deep surface of lateral head of Gastrocnemius & in other case origin from capsule. Bicipital Plantaris was seen where one head was originating from capsule of knee joint and other from lateral condyle. Conclusion: In order to avoid any inadvertent injury during surgical operations, variation of the Plantaris must be borne in mind. Awareness of the insertion pattern of the Plantaris tendon is also important for clinicians in the diagnosis of muscle tears and for surgeons performing reconstructive procedures. Considering the above facts, the existence and importance of the Plantaris muscle cannot be undermined.