Posterior Thigh

Question 1

Gluteus Medius

Answer 1

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

Insertion: Elongate facet on the lateral surface of the greater trochanter

Innervation: L4-L5-S1 Superior gluteal nerve

Actions: Abducts femur at the hip joint, holds pelvis secure over stance leg prevent- ing pelvic drop with gait; medially rotates thigh

Question 2

Gluteus Minimus

Answer 2

Origin: External surface of the ilium between inferior and anterior gluteal lines

Insertion: Linear facet on the anterolateral aspect of the greater trochanter

Innervation: L4-L5-S1 Superior glu- teal nerve

Actions: Abducts femur at the hip joint, holds pelvis secure over stance leg prevent- ing pelvic drop with gait; medially rotates thigh

Question 3

Piriformis

Answer 3

Origin: Anterior surface of the sacrum (S2-4)between anterior sacral foramina

Insertion: Medial side of the superior border of greater trochanter of femur

Innervation: Branches of L5-S1-S2

Actions: Laterally rotates the ex- tended femur at hip joint, abducts flexed femur at hip joint