Deep 6 External Rotators

Question 1

Piriformis

Answer 1

Origin:
- Anterior surface of sacrum
Insertion:
- Medial surface of greater trochanter (through greater sciatic foramen)
Action:
- Medially rotates the hip when hip is flexed past 90°
- Laterally rotates the hip when hip is flexed less than 90°
Nerve:
- Nerve to piriformis
- S1,2

Question 2

Superior Gemellus

Answer 2

Origin:
- Ischial spine
Insertion:
- Tendon of obturator internus
Action:
- Laterally rotates hip 
Nerve:
- Nerve to obturator internus
- L5, S1-2

Question 3

Obdurator Internus

Answer 3

Origin:
- Internal surface of obturator foramen
Insertion:
- Medial aspect of greater trochanter (through lesser sciatic foramen)
Action:
- Laterally rotates hip 
Nerve:
- Nerve to obturator internus  
- L5, S1-2

Question 4

Inferior Gemellus

Answer 4

Origin:
- Ischial tuberosity
Insertion:
- Tendon of obturator internus
Action:
- Laterally rotates hip 
Nerve:
- Nerve to quadratus femoris
- L4-5, S1

Question 5

Obturator Externus

Answer 5

Origin:
- External surface of obturator membrane
Insertion:
- Trochanteric fossa of femur
Action:
- Laterally rotates hip 
Nerve:
- Obturator 
- L2,3,4

Question 6

Quadratus Femoris

Answer 6

Origin:
- Ischial tuberosity
Insertion:
- Quadrate tubercle
Action:
- Laterally rotates hip 
Nerve:
- Nerve to quadratus femoris