Anatomical Locations of the Motor Points of the Triceps Surae Muscles

ABSTRACT

OBJECTIVE: To identify the range of the precise locations of the motor points of triceps surae muscles in relation to bony landmarks. METHOD: Eight limbs of four male cadavers were dissected. The number and location of the motor points from the tibial nerve to each head of the triceps surae muscle were identified related to the bony landmarks. Bony landmarks were medial and lateral epicondyles of the femur, and medial and lateral malleolli of the tibia. The length of the lower leg was defined as the distance from the intercondylar line of the femur to the intermalleolar line of the tibia. The locations of the motor points were expressed as the vertical distance from the intercondylar line, which was normalized to the length of the lower leg. RESULTS: The most proximal motor points of the medial gastrocnemius, lateral gastrocnemius, and soleus were located in 9.6+/-3.5%, 12.0+/-3.4% and 20.5+/-3.9% of the lower leg below the intercondylar line of the femur. The most distal points were in 37.5+/-5.5%, 37.9+/-2.3% and 46.7+/-3.6%. CONCLUSION: The identification of the locations of motor points related to the bony landmarks would increase the ease and accuracy of the motor point blocks to the triceps surae muscles.