Lab 6 - Module 1 - The Gluteal Region: Page 7 of 8

Add the Gluteus Medius muscle which lies between gluteus maximus posteriorly and tensor fasciae lata anteriorly. Much of the muscle is covered by gluteus maximus.

Origin - External surface of the ilium between the anterior and posterior gluteal lines

Insertion - Lateral surface of the greater trochanter

Innervation - Superior Gluteal Nerve

Action - Abducts and medially rotates the femur; keeps pelvis level when opposite leg is raised.

Add the Gluteus Maximus muscle which is a large, coarsely fibered, quadrilateral mass of muscle, which forms the prominence of the buttock and covers the ischial tuberosity.

Origin - Ilium posterior to the posterior gluteal line, dorsal surface of the sacrum and coccyx, and sacrotuberous ligament

Insertion - Gluteal tuberosity of femur, iliotibial tract

Innervation - Inferior Gluteal Nerve

Action - Extends thigh, assists lateral rotation, through its attachment to the iliotibial tract it stabilizes the knee joint when the extensors are relaxed.

Add the Tensor Fascia Lata.

Clinical Correlation - Trendelenburg Test:

The ‘Trendelenburg test’ is conducted with the opposite non-weight bearing hip in extension. This allows the pelvis to be carefully tilted for assessment from the front. Flexion of the opposite hip tends to cause a forced negative result owing to action of the psoas muscle. Both an immediate and a delayed, after 20 to 30 second, Trendelenburg test are checked and correlated with gait and the ability to hop. In a negative test, the hemi-pelvis on the weight bearing side stays low but if the test is positive the muscle forces cannot keep that side of the pelvis down, and it rises. This is due to a number of causes including weakness of the hip abductors (gluteus medius and minimus), short femoral neck and coxa vara.