Shape and innervation of popliteus muscle.

The aim of this study was to delineate the shape of the popliteus muscle and determine the correct motor point site for treating spasticity. A total of 22 legs from 13 fresh Korean cadavers were evaluated. The x-axis was set as a transverse line across the lateral and medial epicondyle of the femur and the y-axis as a vertical line at the midpoint of the medial malleolus of the tibia and lateral malleolus of the fibula. The popliteus muscle is an obtuse triangle in shape. Superior, medial, and inferior angles were 27.2±4.3°, 114.8±19.8°, and 38.0±18.8° respectively. The lengths of the superior, medial, and lateral sides of the triangle were 7.6±1.0 cm, 6.2±1.0 cm, and 11.9±1.5 cm respectively. Nerve branches ran superficially on the periosteum of the tibia and entered the popliteus on its superficial surface. The diverging point of the nerve branch entered the popliteus from the tibial nerve located at the midline of the popliteal fossa and 17% of the leg length above the intercondylar line. Most nerve entry points (83.3%) were within a 2.0×3.0 cm rectangle with the center located at -1.0 cm (-7%) on the x-axis and -3.3 cm (-9%) on the y-axis.