Perineum

Question 1

Where is the perineum?

Answer 1

inferior to the pelvic diaphragm, bounded by the pelvic outlet

Question 2

What are the 2 triangles of the perineum?

Answer 2

urogenital triangle

anal triangle

Question 3

What is the ischioanal fossae?

Answer 3

fat filled space on either side of the anal canal, allow for dilation of the anal canal

lateral wall of each fossae made up of obturator internus and ischial tuberosity

medial wall of each fossae is made of up levator ani and external anal sphincter

Question 4

anterior recesses

Answer 4

the ischioanal fossa project into the UG triangle forming these recesses which facilitate the spread of infection between the UG and anal triangles

they also communicate with each other, facilitating the spread of infection between the left and right sides of the anal triangle

Question 5

Anal canal

Answer 5

begins at anorectal flexure and ends at the anus

• anal columns: vertical folds in the mucosal lining
• anal valves: crescent shaped folds that unite the anal columns inferiorly
• pectinate line: irregular line at level of anal valves, where internal tissue meets external tissue

Question 6

Where is blood supplied/drained superior to the pectinate line?

Answer 6

superior rectal veins (from inferior mesenteric vessels) (portal) and partly middle rectal veins

Question 7

Where does lymph drain superior to the pectinate line?

Answer 7

internal iliac lymph nodes

Question 8

Anal canal is derived from…superior to the pectinate line and ….inferior to the pectinate line

Answer 8

endoderm

ectoderm

Question 9

What supplies/drains anal canal inferior to the pectinate line?

Answer 9

inferior rectal vessels (internal pudendal vessels from internal iliac)

Question 10

Where does lymph drain inferior to the pectinate line?

Answer 10

superficial inguinal lymph nodes

Question 11

Inferior to the pectinate line, anal canal receives somatic innervation from what nerve?

Answer 11

inferior rectal nerve (caval system)

Question 12

In the case of portal hypertension, the increased blood to the inferior rectal veins can lead to…

Answer 12

external hemorrhoids

Question 13

Internal anal sphincter

Answer 13

smooth muscle sphincter

Question 14

What does sympathetic innervation to the internal anal sphincter do? parasympathetic?

Answer 14

contract to prevent defecation via lumbar splanchnic nerves

relax to allow for defecation via pelvic splanchnic nerves

Question 15

external anal sphincter

Answer 15

skeletal muscle

Question 16

What kind of innervation does the external anal sphincter receive? What does it do?

Answer 16

somatic motor innervation via inferior rectal nerves

contract to prevent defecation

Question 17

What are the layers of the perineal fascia covering the UG triangle?

Answer 17

superficial perineal fascia

• SF fatty layer> continuous with camper fascia of abd wall
• deep membranous layer aka colles fascia > continuous with scarpa fascia (or dartos in males)

deep perineal fascia

perineal membrane

Question 18

perineal membrane

Answer 18

attachment for erectile tissue and muscles

urethra and vagina pass through it

Question 19

perineal body

Answer 19

thickening of the posterior border of the perineal membrane where muscles and the perineum insert

Question 20

Weakening of the perineal body can result in…

Answer 20

vaginal prolapse

Question 21

episiotomy

Answer 21

controlled cut through perineal body prior to childbirth to prevent ragged tear

Question 22

vulva/pudendum

Answer 22

external female genitalia

Question 23

labia majora

Answer 23

homologous to scrotum

fat filled folds containing the round ligament of the uterus

Question 24

labia minora

Answer 24

thin folds located on either side of the midline, join together superior to the clitoris to form the prepuce

Question 25

vestibule

Answer 25

space btwn labia majora, contains opening for the urethra and vagina

Question 26

hymen

Answer 26

mucous membrane that spans the vaginal orifice

Question 27

What are the erectile tissues in the female?

Answer 27

clitoris, bulb of the vestibule (both paired)

Question 28

clitoris

Answer 28

corpora cavernosa, supported by the suspensory ligament of the clitoris, extension of deep fascia

Question 29

bulb of the vestibule

Answer 29

paired structure corresponds to corpus spongiosum located on either side of the vaginal opening

Question 30

erectile tissue in male

Answer 30

corpora cavernosa (paired) dorsal body of penis corpus spongiosum (unpaired) ventral body of penis, glans and bulb of penis

Question 31

prepuce

Answer 31

foreskin

Question 32

Skeletal muscle of the UG triangle

Answer 32

ischiocavernosus- paired muscles covering crura, aids in erection bulbospongiosus- paired, covers bulbs, unite in the midline for males superficial transverse perineal muscle- attached to the ischial tuberosities laterally and the perineal body medially, help stabilize

Question 33

What are the deep muscles of the UG triangle?

Answer 33

deep transverse perineal muscles-attach to perineal body, help stabilize external urethra sphincter, surrounds urethra

Question 34

What kind of innervation does the external urethral sphincter receive?

Answer 34

somatic motor innervation via perineal nerves contract to prevent urination

Question 35

parts of the urethra in males (SF to deep)

Answer 35

prostatic urethra, membraneous urethra, penile spongy urethra

Question 36

greater vestibular (bartholin) gland

Answer 36

only in females just posterior to the bulbs of the vestibule, secrete mucous for lubrication into the vestibule

Question 37

bulbourethral (cowper) gland

Answer 37

only in males just lateral to the external urethral sphincter secretes pre-ejaculation into the penile urethra which helps with lubrication and neutralize the urethra

Question 38

Spinal level of sacral plexus

Answer 38

L4-S4 can be compressed by pelvic tumors or the fetal head during childbirth

Question 39

spinal level of lumbosacral trunk

Answer 39

L4-L5

Question 40

What is a major branch of the sacral plexus?

Answer 40

pudendal nerve "S2-S4 keep your junk off the floor"

Question 41

branches of pudendal nerve

Answer 41

inferior rectal nerves, perineal nerves, dorsal nerve of the penis/clitoris

Question 42

inferior rectal veins

Answer 42

innervate the external anal sphincter and skin of anal triangle

Question 43

perineal nerves

Answer 43

innervate the muscles and skin of the UG triangle

Question 44

deep nerve of the penis or clitoris

Answer 44

innervate the skin, particularly glans

Question 45

pudendal nerve block to..

Answer 45

numb the perineum

Question 46

Autonomic controls of sex function

Answer 46

point and shot parasympathetic: via pelvic splanchnic nerves- achieve erection sympathetic: via lumbar splanchnic nerves-emission and contraction of internal urethra spinchter

Question 47

primary source of blood to perineum?

Answer 47

pudendal artery, branch off internal iliac

Question 48

Branches of pudendal artery

Answer 48

inferior rectal artery, perineal arteries, dorsal artery of the penis/clitoris, deep artery of the penis/clitoris

Question 49

where does lymph drain from the deep perineal tissue?

Answer 49

deep perineal tissue> | internal iliac lymph nodes

Question 50

where does lymph drain from the superficial perineal tissue?

Answer 50

superficial perineal tissue> superficial inguinal nodes