3-25 Gluteal Muscles

Question 1

in general, what do the gluteal muscles do

Answer 1

muscles of the buttock
- extend, abduct and laterally rotate the femur at the hip joint
- gluteus maximus is strongest muscle + is used in extension (where it is used to rise from a sitting position + climb stairs)

Question 2

gluteus maximus

Answer 2

proximal attachment:
- ileum posterior to posterior gluteal line
- dorsal surface of sacrum + coccyx
- sacrotuberous ligaments

distal attachment:
- most fibres end in iliotibial tract that inserts into lateral condyle of tibia
- some fibres insert on gluteal tuberosity of femur

innervation:
inferior gluteal nerve (L5-S2)

main actions:
- extends thigh at the hip
- assists in thigh lateral rotation
- steadies thigh
- assists in raising trunk from flexed position

Question 3

gluteus medius

Answer 3

proximal attachment:
external surface of ilium

distal attachment:
lateral surface of greater trochanter of femur

innervation:
superior gluteal nerve (L4-S1)

main actions:
- abducts and medially rotates thigh at hip
- steadies pelvis on limb when opposite limb is raised

Question 4

gluteus minimus

Answer 4

proximal attachment:
lateral surface of ileum

distal attachment:
anterior surface of greater trochanter

innervation:
superior gluteal nerve (L4-S1)

main actions:
- abducts and medially rotates thigh at hip
- steadies pelvis on limb when opposite limb is raised

Question 5

piriformis

Answer 5

proximal attachment:
- anterior surface of sacrum
- sacrotuberous ligament

distal attachment:
superior border of greater trochanter

innervation:
branches of anterior rami (L5-S2)

main actions:
- laterally rotates extended thigh at hip
- abducts flexed thigh at hip
- steadies femoral head in acetabulum

Question 6

obturator internus

Answer 6

proximal attachment:
pelvic surface of obturator membrane + surrounding bones

distal attachment:
medial aspect of greater trochanter of femur

innervation:
nerve to obturator internus (L5-S2)

main actions:
- laterally rotates extended thigh at hip
- abducts flexed thigh at hip
- steadies femoral head in acetabulum

Question 7

gemelli (superior and inferior)

Answer 7

proximal attachment:
- superior: ischial spine
- inferior: ischial tuberosity

distal attachment:
medial aspect of greater trochanter of femur

innervation:
- superior: nerve to obturator internus (L5-S2)
- inferior: nerve to quadratis femoris (L4-S1)

main actions:
- laterally rotates extended thigh at hip
- abducts flexed thigh at hip
- steadies femoral head in acetabulum

Question 8

quadratis femoris

Answer 8

proximal attachment:
lateral border of ischial tuberosity

distal attachment:
quadrate tubercule on intertrochanteric crest of femur

innervation:
nerve to quadratis femoris (L4-S1)

main actions:
laterally rotates thigh at hip

Question 9

CC: what can weakness or paralysis of the gluteus medius + minimus do?

Answer 9

• can lead to an unstable pelvis
• during walking, the pelvis tilts to the unaffected side

Question 10

what are considered the main superficial muscles of the gluteal region

Answer 10

• gluteus maximus
• gluteus medius
• gluteus minimus
• [tensor fascia lata] as this is sometimes considered anterior thigh muscle

Question 11

what are some similarities between gluteus medius + minimus

Answer 11

same general actions of abducting, stabilising + rotating thigh medially, and keeping pelvis level during walking

same innervation by the superior gluteal nerve

same general orgins and insertions
O = external surface of ileum
I = different surfaces of the greater trochanter

common blood supply of superior gluteal artery

both are fan-shaped

Question 12

what are considered the main deep muscles of the gluteal region

Answer 12

from top to bottom
- piriformis
- superior gemellus
- obturator internus
- inferior gemellus
- quadratus femoris

Question 13

what are the general common actions of the piriformis, obturator internus + gemelli

Answer 13

• laterally rotating extended thigh
• abducting flexed thigh
• steadying femoral head in acetabulum