Anatomical variations and dimensions of the popliteus muscle in cadaveric specimens v1
Authors: Virupakshamurthy Murlimanju , Vadgaonkar Rajanigandha 
Published: August 2023

Introduction The popliteus muscle is located at the flexor aspect ofthe leg and is supplied by the tibial nerve. This is the only muscle in theback of leg, which actions on the knee joint and never over the ankle joint.This is considered as the knee’s unlocking muscle. It laterally swaps the femurover tibia, while walking when one foot is on the ground. It also causes medialrotation of the tibia on the femur bone, once the foot is over the ground. Alongwith lateral collateral ligament and popliteo-fibular ligament, the tendon ofpopliteus plays instrumental role in the stabilization of the posterolateral partof knee (1). The lateral femoral condyleand lateral meniscus at its posterior horn, offers the origin of popliteus. Itsorigin is tendinous and it is interesting to know that there exists variabilityin its origin like from the styloid process of the fibula (2). Aims and Objective Thegoal of this investigation is to describe the morphology of popliteus muscle withits tendon in context to its variability in origin, mode of insertion, innervationpatterns and its dimensions. The objectives are to measure the length,thickness and width of the popliteus at various locations. Methodology Study setting: Departmentof Anatomy, Kasturba Medical College, Mangalore Study design: InstitutionalBased Descriptive Cross Sectional Study Study participants:A meticulous dissection will be done in adult human cadaveric lower limbspecimens and the morphology of the popliteus muscle will be tabulated for the statisticalanalysis. Inclusion criteria: Lower limbspecimens with an intact posterior compartment will be included Exclusion criteria: Thespecimens showing fractures, any visible deformities and missing parts will beexcluded. Study duration: 3 months Sample size: 25adult cadavers (25 right and 25 left sided lower limbs) Sampling method: Thesample size is similar to the earlier study performed by Olewnik et al. (1). Data collection methodology: The variability of the origin of popliteusand the insertion of popliteus will be noted down. To study the morphometry,the popliteus muscle is divided into certain sections extending from the originto its final insertion into the posterior surface of the tibia. The parametersconsidered in the study are measuring the length, width and thickness of themuscle belly and its tendon, which will be taken by digital Vernier caliper. Data analysis: Thedata collected as above will be analyzed by applying paired samples t test. Implications The anatomy and biomechanics of popliteus makes it animportant structure, which keeps the knee stable. But its involvement isignored in the complex injury of the knee joint (3). The isolatedinvolvement of popliteus is seen in sports injuries and it may bemisinterpreted as a tear of lateral meniscus. The sports like tennis,basketball and downhill running may put additional stress on the tendon ofpopliteus (3). In this context, the morphometric data of popliteus are clinically important for the effective treatment of thepopliteus muscle spasticity (4).