Perineum - Urogenital and Anogenital Triangles

Question 1

Describe pelvis in general - specifics about triangles

Answer 1

Pelvic diaphragm = U shape, makes 2 triangles (pelvic diaphragm = levator ani - puborectalis, coccygeus), seals pelvic floor
Perinuem = outside pelvic diaphragm

Question 2

Name the 2 triangles of perinuem

Answer 2

Front - anterior = urogenital triangle
Back - posterior = anal (anogenital) triangle

Question 3

Describe pelvic floor

Answer 3

Delineates pelvic and perineal region
Muscular component has tonic role
*puborectalis

Question 4

Describe perineal membrane

Answer 4

Seals urogenital triangle
Tough ct, membrane sealing urogenital triangle so weight of ext genitalia not added to muscle - need to support pelvic organs

Question 5

What is perineal body

Answer 5

Levator ani and perineal membrane anchored
Fibrotic structure —> connects muscles

Question 6

Describe perineum

Answer 6

Diamond shaped space inferior to pelvic floor
Pelvic diaphragm - levator ani and coccygeus muscles
Funnel shaped, with anal aperture at inferior apex
Ischial tube = where you sit on bike
Delineated by bony features and lines

Question 7

Name all margins of perineum

Answer 7

Anterior = inferior aspect of pubic symphysis
Posterior = tip of coccyx
Lateral = ischial tuberosity= ischiopubic rami, sacrotuberous ligament
Ceiling = pelvic diaphragm
Floor = skin

Question 8

What is perineum divided by

Answer 8

An imaginary line between ischial tuberotisties

Question 9

Where are triangles of perineum

Answer 9

Urogenital = anterior
Anal= posterior

Question 10

Give a very general explanation of the 2 triangles and what the boundaries are

Answer 10

Urogenital = sex specific structures and urinary system, join at pubic symphysis, ischial pubic rami
Ischial tube = imaginary line
Anal triangle = apex is Coccyx, sacrotuberous lig laterally

Question 11

Describe urogenital triangle

Answer 11

Oriented in horizontal plane
Pelvis tilted forwards, asis and pubic symohysis in same plane
Basically sitting on it

Question 12

What is urogenital triangle defined by

Answer 12

Laterally = Ischiopubic rami
Posteriorly = Horizontal line between ischial tuberosity, Superficial transverse perineal muscle: to perineal body
Antyeriorly = Pubic symphysis
Roof= is the pelvic diaphragm

Question 13

Describe urogenital hiatus

Answer 13

U shaped opening in levator ani
Closed by perineal membrane - thick fibrous sheet
For urinary and genital systems
Pelvic diaphragm open at central line

Question 14

Describe where deep perineal pouch is

Answer 14

Between levator ani and perineal membrane

Question 15

Describe role of urogenital triangle

Answer 15

Provide support to ext genitalia and support of pelvic viscera

Question 16

Compare urogenital to anal triangle

Answer 16

Anal trinagle = facing more posterior - back

Question 17

Describe perineal membrane of urogenital triangle - gen

Answer 17

Triangular, fibrous sheet,
Between ischiopubic rami, pubic symphysis, ischial tuberosities

Question 18

Describe perineal membrane of urogenital triangle - specifics

Answer 18

Posterior edge free - floats, except at perineal body
Attach point for erectile tissue and their muscles
Contains urethral openings and vaginal opening in afab

Question 19

Describe perineal body of urogenital triangle

Answer 19

Central tensions structure of perineum
Between urogenital and anal triangles

Question 20

What attaches at perineal body of urogenital triangle

Answer 20

Muscles of pelvic floor - levator ani and perinuem attach (bulbospongiosus, transverse perineal muscles)

Question 21

Compare afab vs amab urogenital triangle

Answer 21

Amab = diff
Urethra opening anchored in perineal membrane directly
Afab = urethral opening and vaginal openings contained in membrane

Question 22

Describe episiotomy

Answer 22

Enlarge vaginal opening - episiotomy, now done to avoid perineal body, - helps maintain dynamic integrity

Question 23

Describe deep perineal pouch

Answer 23

Between perineal membrane and pelvic diaphragm
Contains thin muscular sheet = sphincters for urethra, thin deep layer, smooth muscle, Sphincters to close orifices

Question 24

Name a muscle that is important for urogenital trinagle

Answer 24

Superficial transverse perineal muscle
Core, tone, to membrane, provide more tension, ischial tuberosity to perineal body

Question 25

Describe anal triangle

Answer 25

Oriented postero inferior Not flat, more dome shaped

Question 26

What is anal triangle defined by

Answer 26

Laterally = sacrotuberous ligament Anteriorly = horizontal line between ischial tuberosity Posteriolry = coccyx Roof= pelvic diaphragm

Question 27

Describe anal aperture

Answer 27

Funnel shaped levator ani’s central opening

Question 28

What is external anal sphincter

Answer 28

Surrounds anal canal, after passing through levator ani

Question 29

Describe what anal aperture and external anal sphincter do

Answer 29

Divide anal triangle in 2 lateral spaces = ischioanal fossa

Question 30

What are ischioanal fossae

Answer 30

Paired wedge shaped spaces on either side of anal canal, filled with adipose tissue Tilted anteriorly

Question 31

What are ischioanal fossa defined by

Answer 31

Superiorly = pelvic diaphragm Laterally = ischium and sacrotuberous ligament Ifneiorly = skin of anal region

Question 32

What is role of ischioanal fossae

Answer 32

Allows for movement of pelvic diaphragm - puborectalis needs to relax so needs soft tissue here so can expanded Allows movement of pelvic diaphragm Expansion fo anal canal during defecation Possess of internal pudendal vessels, pudendal nerve and associated brnaches

Question 33

What is found near ischioanal fossa

Answer 33

N/v = in pudendal canal Away from levator ani (since would stretch vessels) and close to bone = embedded in fascia of obturator muscle

Question 34

Describe anterior recesses

Answer 34

Ischioanal fossa of anal trinagle projects anteriorly in urogenital triangle Forms 2 anterior reccesses on each side = anterior recess of ischioanal fossae Space between dome shaped levator ani and perineal body, continuous with ischioanal fossa and forms recess

Question 35

What are anterior reccesses defined by

Answer 35

Superomedial wall = levator ani Lateral wall = obtruator internus Floor = deep perineal pouch, and perineal membrane, not skin, solid floor

Question 36

Describe what passses through anterior reccesses

Answer 36

Where levator ani enlarges when need Vessels continue in space to where they need to go

Question 37

Describe blood supply of perineum

Answer 37

Internal pudendal artery

Question 38

Describe entire pathway of internal pudendal artery

Answer 38

From anterior trunk of internal illiac artery —> leaves pelvic cavity through greater sciatic for amen inferior to piriformis —> Passes lateral to ischial spine —> Reaches perineum through lesser sciatic for amen —> Enters pudendal canal (alcocks) formed by obturator internus muscles fascia

Question 39

What does internal pudendal artery supply

Answer 39

Erectile tissue, perineum, inferior rectum

Question 40

What branches does internal pudendal artery give

Answer 40

Inferior rectal artery Perineal arteries = erectile tissues and muscles, skin, scrotum, labia and bulb glands

Question 41

Describe innervation perineum

Answer 41

Pudendal nerve - s2-3-4 = motor and sensory

Question 42

Describe pathway of perineum n/v generally

Answer 42

Vessels use for amen to leave and then loop back and travel to perineum - pudendal canal

Question 43

Why is it called pudendal nerve and not internal pudendal nerve

Answer 43

Arteries = called internal pudendal Nerve = just pudendal since no external

Question 44

What is pudendal block

Answer 44

Episiotomy or procedure Palpate spine and inject and numb nerve Since pudendal nerve goes around ischial spine

Question 45

Describe pathway of pudendal nerve

Answer 45

Leaves pelvic cavity through greater sciatic formaen inferior to piriformis —> Passes around sacrospinous ligament, loops over ischial spine —> Through lesser sciatic foreman to reach perineum —> Enters perineum through pudendal canal - alcocks with internal pudendal arteries

Question 46

What does pudendal nerve inervate

Answer 46

Somatic innervation of perineum and associated structures

Question 47

Name branches off pudendal nerve

Answer 47

Inferior rectal Perineal nerve Dorsal nerve of penis/clitoris

Question 48

Describe inferior rectal nerve

Answer 48

Sensory = anal region Motor = external anal sphincter

Question 49

Describe perineal nerve

Answer 49

Sensory = perinuem Motor= muscle of ext genitalia

Question 50

Describe dorsal nerve of penis/clitoris

Answer 50

In anterior recess sensory to penis/clitoris

Question 51

Describe path of pudendal vessels and nerve

Answer 51

Greater sciatic, piriformis = leaves pelvic and loops back in outside pelvic diaphragm = leaves Cavoty and bypasses levator ani insertion and now in perinuem