The main muscles of the hip and pelvis consist of the iliopsoas, pectineus, rectus femoris, and sartorius at the front. The gluteus medius, gluteus minimus, piriformis, tensor fasciae latae on the outside. Gluteus maximus, biceps femoris, semitendinosus, semimembranosus at the back and the adductor or groin muscles (adductor brevis, adductor longus, adductor Magnus, and gracilis).
Gracilis is another muscle that works in conjunction with the groin muscles or adductors.
Adductor Magnus is the largest of the adductor muscles and the gracilis muscle forms the long adductor group.
Adductor Longus is the middle of the three short adductor muscles (adductor brevis and pectineus are the other two). The adductor magnus and gracilis are the two long adductor muscles that go from the pubic bone to the knee.
Adductor Brevis is the smallest and shortest of the five adductor muscles with the others being Adductor longus, Adductor magnus, Gracilis and Pectineus.
Tensor Fasciae Latae
The Tensor Fasciae Latae is a small muscle which attaches inferiorly to the long thick strip of fascia, known at the iliotibial band (ITB)
The Rectus Femoris muscle is part of the Quadriceps muscle group. It is the only muscle of the group which crosses the hip joint and is a powerful knee extensor when the hip is extended but is weak when the hip is flexed.
The Sartorius is a two joint muscle and so is weak when the knee is flexed and the hip is flexed at the same time. It works better during single movements.
Pectineus is positioned between the Iliopsoas and Adductor Longus muscles.
The Piriformis muscle is an important muscle. The sciatic nerve passes underneath this muscle on its route down to the posterior thigh. In some individuals, the nerve can actually pass right through the muscle. This can lead to sciatica symptoms due to a condition known as piriformis syndrome.
Gluteus Maximus is the largest and most superficial of the three gluteal muscles.
Gluteus Medius is an important muscle in controlling the level of the hips. Weaknesses in gluteus medius often result in a trendelenburg sign, an abnormal gait cycle where the hip of the swinging leg drops down, rather than raises up. This results in increased degrees of knee flexion in order to clear the ground.
Iliopsoas is sometimes classified as two muscles, Iliacus and Psoas major.