Do you want to slim down inner & outer Thighs? We have a serious thighs workout for you. The inner and outer thigh muscles are often neglected in traditional exercise programs. Your inner thigh comprises of three main muscles: the adductor magnus, the adductor longus, and the gracilis. These muscles originate in the pelvic area and run down toward your knee along the inside of your thigh. These muscles work as a unit to perform hip adduction and help stabilise the hips.