Pelvic Muscles And Obturator Internus

Question 1

Pelvis muscles

Answer 1

1. Pelvic wall muscles
2. Pelvic floor muscles (pelvic diaphragm)

Question 2

Pelvic wall muscles

Answer 2

1. 2 Obturator internus muscles: on front and lateral wall
2. 2 piriformis muscles: on posterior wall

Question 3

Origin

Answer 3

1. Inner margins Obturator foramen
2. Inner surface Obturator membrane
3. Inner surface bony pelvis between Obturator and greater sciatic foramina

Question 4

Insertion

Answer 4

Tendon leaves pelvis via lesser sciatic foramen to
insert in medial surface of femur greater trochanter

Question 5

Nerve supply

Answer 5

Nerve to obturator internus from sacral plexus

Question 6

Action

Answer 6

Thigh lateral rotation

Question 7

Obturator fascia

Answer 7

1. Covers it’s medial surface
2. Forms white line which gives origin to levator ani
3. Splits forming
   pudendal (Alcock’s) canal in lateral wall of ischiorectal fossa