The hip adductor muscles help to bring your legs together and rotate your hip inwards towards the midline of your body. The short adductors include the pectineus, adductor brevis, and adductor longus, and the long adductors include the adductor magnus and gracilis. All of these muscles are located on the inside of your thigh. At the end of these muscles are tendons, which are tough, fibrous tissues that connect your muscles to your bones. Most of these muscles and tendons attach your pubic bone (lower part of the pelvis) to your thigh bone (femur); however the gracilis muscle attaches to the lower leg bone (tibia) not the femur. These muscles and tendons start in the groin (crease at the junction of the inner part of the thigh where it meets the body near the external genital area) and move down through the inner thigh to the inside of the knee.
Your hip flexor muscles are among the most powerful muscles and tendons in your body. They are comprised of your iliopsoas (deep set muscles at the front of your hip), your tensor fasciae latae (outer hip muscle), and your rectus femoris and sartorius (they lie over top of the iliopsoas muscles in your front, upper thigh area). Hip flexors help you lift your upper leg to your torso or flex your torso towards your thigh (like when sitting up from a lying down position), they externally rotate your spine and thigh bone, and also limit your hip extension when walking or running.
Although it is often regarded as a single muscle, the iliopsoas is comprised of 2 muscles: the psoas major and the iliacus (psoas minor Ð weak flexor muscle) which lie deep beneath your skin surface. The psoas muscle lies at the front of your hip. It starts in your lower back, attaches to the base of your sacrum (triangular bone that forms the bottom of your spine and the back part of your pelvis) on the inner surface of your ilium (the upper and widest part of the pelvis/hip bone) and ends on the top of your femur (thigh bone). The iliacus starts from your hip bone/ilium, and attaches across to the inner surface of your lower spine and sacrum. It also ends at the top of your femur. Both of these muscles come together via the same tendon (thick, fibrous tissue that connects muscle to bone) and attach to the bump on the inside of the shaft of your femur (the lesser trochanter) - this is where most injuries occur.