The 4 major groups of muscles in the thigh are Flexors, extensors, abductors and adductors. The thigh muscles are the largest group of the lower extremity. They can be separated into two parts. The strongest muscle group of the anterior part is quadriceps, they consist of the rectus femoris, vastus intermedius, vastus lateralis and vastus medialis. The main muscle group of the posterior part is the hamstrings; they consist of the biceps femoris, semimembranosus and semitendinosus. Those muscles play a major role in moving and stabilizing the knee joint. The triceps surae consist of gastrocnemius and soleus. Its tendons go along the posterior part of the leg and then form the Achilles tendon at the ankle level. The peroneal muscles go through laterally, they perform the eversion motion.