Pelvis: Pelvic Muscles

Question 1

enumerate pelvic wall muscles

Answer 1

• 2 obturator internus: anterolateral wall of pelivs
• Piriformis: posterior wall of pelvis

Question 1

Origin of obturator internus

Answer 1

• Inner margins of obturator foramen
• Inner surface of obturator membrane
• inner bony surface between greater sciatic notch & obturator foramen

Question 2

Insertion of Obturator internus

Answer 2

tendon leaves pelvis through lesser sciatic foramen & inserts in medial surface of greater trochanter of femur

Question 3

Nerve supply of Obturator internus

Answer 3

nerve to obturator internus

Question 4

Action of obturator internus

Answer 4

• Lateral rotation of thigh
• its covering is obturator fascia which has white line that gives origin to levator ani + it forms pudendal canal between the fascia and the muscle

Question 5

Origin of piriformis muscle

Answer 5

front of Middle 3 sacral pieces

Question 6

Another name for anterior fibers of levator ani

Answer 6

• In male: levator prostate
• In female: sphinctor vaginae (pubovaginalis)

Question 7

Another name for Middle fibers of Levator ani

Answer 7

Puborectalis

Question 8

Another name for posterior fibers of levator ani

Answer 8

Iliococcygeus

Question 9

Origin of anterior fibers of levator ani

Answer 9

inner surface of body of pubic bone

Question 10

Insertion of anterior fibers of levator ani

Answer 10

aka levator prostate/ sphincter vaginae
* moves backwards and medially
* mainly inserts in perineal body
* some fibers insert in coccyx tip (known as pubococcygeus)

Question 11

origin of middle fibers of levator ani

Answer 11

white line of obturator fascia

Question 12

Insertion of middle fibers of levator ani

Answer 12

aka puborectalis:
makes a U-shaped loop around anorectal junction & attaches to fibers of the opposite side

Question 13

Origin of posterior fibers of levator ani

Answer 13

inner surface of ischial spine

Question 14

insertion of posterior fibers of levator ani

Answer 14

aka iliococcygeus:
* insert in ano-coccygeal ligament (body/raphe)
* coccyx last 2 pieces

Question 15

attachement of ano-coccygeal body/raphe

Answer 15

• tip of coccyx
• anal canal
• (sometimes post. fibers of levator ani/ iliococygeus attaches to it)

Question 16

Nerve supply of levator ani

Answer 16

• upper surface: S4 directly from sacral plexus
• Lower surface: inferior rectal branch of pudendal N (S2,S3,S4)

Question 17

Action of levator ani muscles

Answer 17

• Supports pelvic viscera in position
• Raises intra-abdominal pressure for straining (defecation, labour, etc)
• Sphincter action of sphincter Vaginae or puborectalis

Question 18

Pelvic (superior) surface relations of levator ani

Answer 18

• Sup. pelvic fascia
• urinary bladder
• rectum
• in male: prostate
• In female: uterus & vagina

Question 19

Perineal (inferior) surface relations of Levator ani

Answer 19

Inferior plevic fascia

Question 20

Anterior relations of Levator Ani

Answer 20

• Male: prostate & uerthra
• female: Urethra & Vagina

Question 21

posterior relations of levator ani

Answer 21

coccygeus muscle

Question 22

origin of coccygeus muscle

Answer 22

Ischial spine

Question 23

insertion of coccygeus

Answer 23

last sacral & 1st coccygeal

Question 24

Nerve supply of coccygeus

Answer 24

S4 & S5 sacral plexus

Question 25

Action of coccygeus

Answer 25

supports coccyx during delivery & defecation