Details
Gluteus maximus muscle
These specimens show the gluteus maximus muscle and the structures lying deep to the gluteus maximus muscle.
The Gluteus muscle is the largest, most superficial muscle of the gluteal region. It takes origin from the posterior part of the gluteal surface of the ilium, the dorsal segment of the iliac crest, dorsal surface of sacrum and the coccyx and the sacrotuberous ligament. It is inserted into the iliotibial tract and the gluteal tuberosity of the femur. It is supplied by the inferior gluteal nerve (L5, S1, S2). It is the chief extensor of the hip joint. Numerous structures such as the gluteus medius, the gluteus minimus, the piriformis, the obturator internus, the gemelli, the quadratus femoris, the superior gluteal nerve and vessels, the inferior gluteal nerve and vessels, the sciatic nerve and the posterior cutaneous nerve of the thigh can be observed deep to the gluteus maximus muscle.
Iliotibial tract:
The iliotibial tract is the thickened deep fascia of the thigh extending from the hip bone to the upper end of tibia. It is seen along the lateral aspect of the thigh. In its upper part, it receives the insertion of the tensor fascia lata and the gluteus maximus muscles. It stabilizes the knee during locomotion.
Gluteus medius:
The gluteus medius takes origin from the gluteal surface of the ilium (between the posterior gluteal line and anterior gluteal line) and inserts into the greater trochanter. It is supplied by the superior gluteal nerve (L4, L5, S1). It is the abductor of the hip joint and prevents the unsupported side of the pelvis from sagging during walking. Its paralysis leads to a clinical condition known as the Trendelenburg’s sign, where the pelvis sags on the healthy side if that foot if off the ground. Thus the person walks with a lurching gait.
Gluteus minimus:
The gluteus minimus takes origin from the gluteal surface of the ilium (between the anterior gluteal line and inferior gluteal line) and inserts into the greater trochanter. It is supplied by the superior gluteal nerve (L4, L5, S1). It is the abductor of the hip joint and prevents the unsupported side of the pelvis from sagging during walking. Its paralysis leads to a clinical condition known as the Trendelenburg’s sign, where the pelvis sags on the healthy side if that foot if off the ground. Thus the person walks with a lurching gait.
Piriformis:
The piriformis takes origin from the pelvic surface of the sacrum and inserts into the tip of the greater trochanter. It is supplied by the ventral rami of S1, S2. It is the lateral rotator of thigh at the hip joint. It is considered to be a key muscle of the gluteal region since it is related to a number of structures in the gluteal region. Its upper border is related to the superior gluteal nerve and vessels and its inferior border is related to the sciatic nerve, the posterior cutaneous nerve of thigh, the inferior gluteal vessels and nerve.
Obturator internus:
The obturator internus takes origin from the pelvic surface of the obturator foramen and the obturator fascia and inserts in to the medial surface of the greater trochanter of the femur. It is supplied by the nerve to obturator internus (ventral rami of L5, S1, S2).
Gemelli:
The gemelli (superior and inferior) are present above and below the obturator internus respectively. The superior gemellus is supplied by the nerve to obturator internus (ventral rami of L5, S1, S2) and the inferior gemellus is supplied by the nerve to quadratus femoris (ventral rami of L4, L5, S1).
Quadratus femoris:
The quadratus femoris takes origin from the dorsal surface of the body of the ischium and inserts into the quadrate tubercle of the femur. It is supplied by the nerve to quadratus femoris (ventral rami of L4, L5, S1).
Superior gluteal nerve:
The superior gluteal nerve supplies the gluteus medius and the gluteus minimus muscles. Its root value is L4, L5, S1. Its damage leads to paralysis of the muscles supplied by it, which is manifested by the Trendelenburg’s sign.
Inferior gluteal nerve:
The inferior gluteal nerve supplies the gluteus maximus muscle. Its root value is L5, S1, S2). Its damage can lead to paralysis of the muscle supplied by it.
Sciatic nerve:
The sciatic nerve is the thickest nerve of the body. Its root value is L4, L5, S1, S2 and S3. It is formed in the pelvis. It enters the gluteal region by passing through the greater sciatic notch. It is related to the lower border of piriformis muscle. It passes downwards and enters the back of the thigh to supply the hamstring muscles. It damage leads to foot drop, in which case, the dorsiflexion of the foot is not possible.
Posterior cutaneous nerve of the thigh:
The posterior cutaneous nerve of thigh is related to the lower border of piriformis muscle. Its root value is ventral rami of S1, S2, S3. It supplies the skin of the gluteal region and the back of the thigh.
Content partner
