Levator Ani

Question 1

Levator ani

Answer 1

1. Wide thin sheet
2. Linear origin from lesser pelvis walls
3. Fibers of both sides meet in middle line forming gutter for passage of urethra, vagina, and rectum

Question 2

Origin anterior fibers

Answer 2

From inner surface of pubic bone body

Question 3

Origin middle fibers

Answer 3

From white line (horizontal linear thickening in
obturator fascia covering obturator internus medial surface)

Question 4

Origin posterior fibers

Answer 4

From inner surface of ischial spine

Question 5

Insertion anterior fibers

Answer 5

1. Pass backward & medial towards midline to insert mainly in perineal body
2. Few fibers are attached to coccyx tip (sometimes called pubococcygeus)

Question 6

Insertion anterior fibers: male

Answer 6

1. Called levator prostatae,
2. Pass lateral and inferior supporting prostate

Question 7

Insertion anterior fibers: female

Answer 7

1. Called sphincter vaginae (pubovaginalis)
2. Pass across vagina sides

Question 8

Insertion middle fibers

Answer 8

Puborectalis:
1. Pass around recto-anal angle to blend
with opposite side fibers
2. Form U-shaped loop around anorectal junction

Question 9

Insertion posterior fibers

Answer 9

Iliococcygeus:
In anococcygeal body or raphe (extends from coccyx tip of to anal canal in midline) & in coccyx last 2 pieces

Question 10

Nerve supply

Answer 10

1. Superior surface: Direct branches from sacral plexus (S4).
2. Inferior surface: Inferior rectal branch of pudendal nerve (S2,3,4).

Question 11

Action

Answer 11

1. Supports pelvic viscera in position
2. Raises intra-abdominal pressure with other muscles in all straining
   processes as in defecation & labour
3. Sphincteric action:
   - Sphincter vaginae
   - Puborectalis part

Question 12

Sphincter vaginae

Answer 12

1. Supports vagina during fetal head descent during labor
2. Injury of levator ani causes uterine prolapse

Question 13

Puborectalis part

Answer 13

1. Keeps anorectal angle always closed except during
   defecation
2. Reinforces external anal sphincter playing important role in fecal continence

Question 14

Relations: pelvic surface

Answer 14

1. Covered by superior fascia of pelvic diaphragm
2. Related to:
   - Urinary bladder & rectum in both sexes
   - Uterus & vagina: in female
   - Prostate: in male

Question 15

Relations: perineal surface

Answer 15

1. Covered by inferior fascia of pelvic diaphragm
2. Forms ischiorectal fossa medial wall

Question 16

Relations: anterior border

Answer 16

Each muscle has free anterior border which is separated from its fellow by median triangular space through which descends:
1. Male: prostate and urethra
2. Female: vagina and urethra

Question 17

Relations: posterior border

Answer 17

Related to coccygeus