Deep Gluteal Muscles

Question 1

What are the attachments of the piriformis muscle?

Answer 1

Originates from anterior surface of sacrum, travels through greater sciatic foramen and inserts into greater trochanter of femur

Actions: Lateral rotation and abduction.
Innervation: Nerve to piriformis.

Question 2

What are the actions of the piriformis muscle?

Answer 2

Lateral rotation and abduction

Question 3

What is the innervation of the piriformis?

Answer 3

Nerve to piriformis (branch of sacral plexus)

Question 4

What are the attachments of the obturator internus?

Answer 4

Originates from pubis and ischium at obturator foramen, travels through lesser sciatic foramen and attaches to greater trochanter of femur

Question 5

What are the actions of the obturator internus?

Answer 5

Abduction and lateral rotation of lower limb

Question 6

What is the innervation of the obturator internus?

Answer 6

Nerve to obturator internus (branch of sacral plexus)

Question 7

Which tendon separates the two gemelli muscles?

Answer 7

Separated by tendon of obturator internus

Question 8

What are the attachments of the gemelli?

Answer 8

. Superior gemellus originates from ischial spine, attaches to greater trochanter
. Inferior gemellus originates from ischial tuberosity, attaches to greater trochanter

Question 9

What is the function of the gemelli?

Answer 9

Abduction and lateral rotation

Question 10

What is the innervation of the gemelli?

Answer 10

. Superior gemellus innervated by nerve to obturator internus
. Inferior gemellus innervated by nerve to quadratus femoris

Question 11

What are the attachments of the quadratus femoris?

Answer 11

Originates from lateral side of ischial tuberosity, attaches to quadrate tuberosity on intertrochanteric crest

Question 12

What is the function of the quadratus femoris?

Answer 12

Lateral rotation

Question 13

What is the innervation of the quadratus femoris?

Answer 13

Nerve to quadratus femoris (branch of sacral plexus)

Question 14

Why is the piriformis an important anatomical landmark?

Answer 14

. As piriformis travels through greater sciatic foramen, it divides the gluteal region into an inferior and superior part
. Superior gluteal nerve and vessels come into gluteal region superior to piriformis
. Inferior gluteal nerve and vessels come into gluteal region inferior to piriformis
. Sciatic nerve enters gluteal region directly inferior to piriformis, visible as a flat band (approx. 2cm wide)