MSK Muscles of the gluteal region

Question 1

What are the 2 broad groups of the gluteal muscles and name the muscles in each group?

Answer 1

The superficial abductors and extenders
(glut max med min, tensor fascia lata)

The deep lateral rotators
(quadratus femoris, piriformis, gemellus sup and inf, obturator internus)

Question 2

What are the attachments and actions of the gluteal maximus?

Answer 2

Originates from gluteal surface of ilium, sacrum and coccyx
Inserts into iliotibial tract and greater trochanter of femur

Actions:
Main extensor of thigh
Assists with lateral rotation when force is required eg running or climbing

Question 3

What are the attachments and actions of the gluteal medius?

Answer 3

Originates from gluteal surface of ilium
Inserts onto lateral surface of greater trochanter

Actions:
Abducts and medial rotates
Secures pelvis during walking preventing pelvic drop of opposite limb

Question 4

What are the attachments and actions of the gluteal minimus?

Answer 4

Originates from ilium and converges to form a tendon which attaches to anterior side of greater trochanter

Actions:
Abducts and medial rotates
Secures pelvis during walking preventing pelvic drop of opposite limb

Question 5

What are the attachments and actions of the tensor fascia lata?

Answer 5

Originates from anterior iliac crest attaching to ASIS
Inserts into the iliotibial tract which attaches to the lateral condyle of tibia

Actions:
Abducts and medial rotates

Question 6

What is the innervation of the superficial abductors and extenders? (glut max med min, tensor fascia lata)

Answer 6

Glut max = inferior gluteal nerve

Glut med min and tensor fascia lata = superior gluteal nerve

Question 7

What happens if there is damage to the superior gluteal nerve?

Answer 7

Innvervates glut med and min which support pelvis during walking.
If the nerve is paralysed you see ‘Tendelenbergs sign’ which is where the pelvis drops on the lifted leg.
It is detected by looking at the level of the iliac crests on both sides

Question 8

What are the attachments and actions of the piriformis?

Answer 8

Most superior of the deep muscles

Originates from anterior sacrum and travels infero-laterally through greater sciatic notch to greater trochanter

Actions:
Lateral rotation and abduction

Question 9

What are the attachments and actions of the obturator internus?

Answer 9

Originates from pubis and ischium at the obturator foramen
Travels through lesser sciatic foramen and attaches to greater trochanter

Actions:
Lateral rotation and abduction

Question 10

What are the attachments and actions of the gemelli superior and inferior?

Answer 10

2 triangular muscles separated by the obturator internus tendon

Superior originates from ischial spine and inferior from ischial tuberosity
Both attach to greater trochanter

Actions:
Lateral rotation and abduction

Question 11

What are the attachments and actions of the quadratus femoris?

Answer 11

Flat square most inferior of the deep gluts

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

Actions:
Lateral rotation

Question 12

What innervates the deep gluteal muscles? (piriformis, gemelli sup + inf, obturator internus, quadratus femoris)

Answer 12

Piriformis - nerve to piriformis
Obturator internus - nerve to obturator internus
Quadratus femoris - nerve to quadratus femoris

Superior gemellus - nerve to obturator internus
Inferior gemellus - nerve to quadratus femoris

Question 13

Why is the piriformis muscle an important anatomical landmark of the gluteal region?

Answer 13

As the muscle travels through the greater sciatic foramen it divides the gluteal region into an inferior and superior part.

This determines the names of the nerves and vessels
eg the superior glut nerve emerge superiorly to the piriformis and visa versa for the inferior nerve

Also the piriformis can be used to locate the sciatic nerve as it enters the glut region directly inferior to the piriformis