Gluteus maximus muscle
The gluteus maximus is the most superficial gluteal muscle that forms the prominence of the gluteal region. Along with the gluteus medius, gluteus minimus and tensor fasciae latae, it belongs to the gluteal group of the hip muscles. Gluteus maximus extends from the pelvis to the gluteal tuberosity of femur. It is innervated by the inferior gluteal nerve (L5-S2).
The main functions of the gluteus maximus muscle are the extension and external rotation of the thigh at the hip joint. Additionally, its superior part can produce thigh abduction, while the inferior part causes the thigh adduction.
Lateroposterior surface of sacrum and coccyx, gluteal surface of ilium (behind posterior gluteal line), thoracolumbar fascia, Sacrotuberous ligament
Iliotibial tract, gluteal tuberosity of femur
Hip joint: Thigh extension, thigh external rotation, thigh abduction (superior part), thigh adduction (inferior part)
|Innervation||Inferior gluteal nerve (L5, S1, S2)|
Inferior gluteal and superior gluteal arteries
In this article, we will discuss the anatomy and function of the gluteus maximus muscle.
Origin and insertion
The gluteus maximus muscle originates from several sites; the posterolateral aspect of the sacrum and coccyx, the sacrotuberous ligament, gluteal surface of ilium (behind the posterior gluteal line), thoracolumbar fascia and gluteal aponeurosis. The muscle fibers take an inferolateral course, converging towards the femur.
The most superficial three-quarters of the muscle form a tendinous lamina that inserts between the two layers of the fascia lata, thus contributing to the formation of the iliotibial tract. The remaining deep one-quarter of the muscle inserts to the gluteal tuberosity of femur via a broad aponeurosis.
The gluteus maximus is the most superficial and the largest of all three gluteal muscles. It is enveloped with a thin fascia that separates the muscle from the adjacent subcutaneous tissue.
The deep surface of the gluteus maximus muscle covers a number of structures; gluteus medius muscle, pelvic bones, the proximal attachments of the hamstring muscles and several lateral rotators of the hip (piriformis, inferior gemellus, superior gemellus and obturator internus muscles).
The deep surface of the muscle is also in relation to the three bursae:
- The trochanteric bursa separates the muscle from the greater trochanter.
- The ischiofemoral bursa, when present, is situated on the tuberosity of the ischium.
- The gluteofemoral bursa is found between the tendon of the gluteus maximus and that of the vastus lateralis.
Gluteus maximus receives its innervation from the inferior gluteal nerve (root value L5-S2).
The gluteus maximus muscle exhibits four actions on the hip joint; extension, external rotation, abduction and adduction of the thigh.
When its proximal attachment is fixed, gluteus maximus acts as the main extensor of the hip joint, pulling the shaft of the femur posteriorly. The external rotation of the thigh happens simultaneously with the extension, assisting in raising the medial longitudinal arch of the foot.
On the contrary, when its distal attachment is fixed, gluteus maximus pulls the pelvis posteriorly. As it usually happens in synergy with the same action of the hamstring muscles, this action of gluteus maximus helps to bring the trunk from a flexed to an upright position. Furthermore, these muscles help in maintaining the upright posture by balancing the pelvis on femoral heads.
The superior portion of the muscle participates in the abduction of the thigh, while the inferior part participates in its adduction. Additionally, the latter portion tenses the fascia lata and stabilizes the femur from the lateral aspect of the knee joint.
Unlike the other gluteal muscles, the gluteus maximus is not active while standing; instead, it intermittently activates while walking or climbing. While sitting down, the static contraction of gluteus maximus is important for relieving the pressure of the weight of the trunk on the ischial tuberosities.
To expand your knowledge on the muscles of the hip and thigh check out our other articles, videos, quizzes and labeled diagrams.