Lecture 8 - The Perineum

Question 1

anal triangle

Answer 1

Connects from the coccyx bone to the ischial tuberosity

Question 2

what is the border between the anal canal and the rectum?

Answer 2

It is at the puborectalis muscle

Question 3

What controls our anal canal?

Answer 3

• We have an internal sphincter, which is smooth muscle and is controlled by both sympathetics and parasympathetics. The sympathetics keep the internal sphincter tonically closed whereas the parasympathetics open it when it is time to defecate.
• external sphincter - skeletal muscle and under our control

Question 4

Pectinate Line

Answer 4

separates things that are from hindgut origin (endoderm) vs. Proctodeum derived (ectoderm)

Question 5

Innervation above vs. below pectinate line

Answer 5

Above: Motor is autonomic
- Sensory - visceral afferent, pressure
Below: motor it somatic (all is pudendal)
- Sensory - somatic afferent, pain, touch, temperature

Question 6

Blood supply above vs. below pectinate line

Answer 6

Above: Arterial - superior rectal (inferior mesenteric)
- venous - superior rectal (portal)
Below: Arterial - inferior rectal (internal iliac)
- venous - inferior rectal (caval)

Question 7

Lymphatic Drainage above vs. below

Answer 7

Above: Internal iliac nodes
Below: superficial inguinal nodes

Question 8

Hemmorhoids above vs. below

Answer 8

Above: internal
Below: external

Question 9

Pudendal Canal

Answer 9

in the perineal portion of the obturator internus muscle. Has all of the pudendal nerves and vessels in here.

Question 10

Urogenital Hiatus

Answer 10

Area of the levator ani that the vagina and urethra go through

Question 11

Urogenital Diaphragm (Male)
- and 3 steps to making it

Answer 11

Basically it contains the deep perineal pouch and has sphincteric control of the urethra and vagina.

1) Lay down a superior layer of facia from ramus to ramus
- covers urogenital hiatus
2) lay down skeletal muscle from ramus to ramus
- sphincter urethrae and deep transverse perineal muscle
3) lay down inferior layer of fascia from ramus to ramus
- named perineal membrane

Question 12

Contents of the deep perineal pouch in the male

Answer 12

• sphincter urethrae muscle
• deep transverse perineal muscle
• bulbourethral glands (lubricates urethra)
• blood vessels and nerves
• membraneous urethra

Question 13

Deep perineal pouch contents (female)

Answer 13

• sphincter urethrae muscle
• deep transverse perineal muscle
• blood vessels and nerves
• urethra and vagina

Question 14

Construct male genitalia

Answer 14

1) Attach erectile bodies to UG diaphragm
2) Deep penile fascia ( bucks fascia)
3) skeletal muscle
4) Superficial perineal fascia
5) Skin

Question 15

Erectile bodies in male

Answer 15

corpora cavernosa - attach to ischiopubic rami and diaphragm

corpus spongiosum - bulb of penis, attaches to the midline to the perineal membrane of the UG diaphragm

Question 16

Skeletal muscle in the penis

Answer 16

Ischiocavernosus - covers the cruras
bulbospongiosum - squeezes the bulb that contains the urethra to make sure that you get everything out during ejaculation and urination.
superior transverse perineal muscle - meet at the central tendon

Question 17

Superficial perineal pouch

- borders and contents

Answer 17

Lies superficial to the deep perineal pouch. It’s borders are the perineal membrane on top and the superficial perineal fascia (colle’s fascia) on bottom.
contents - erectile bodies, skeletal muscle, fascia, blood vessels and nerves, spongy urethra

Question 18

Superficial perineal fascia

Answer 18

scarpas –> dartos –> colle’s

Question 19

Urethral tears

Answer 19

blood will pool in different places depending on where the tear occurs. If it is like a motorcycle accident then you can tear the urethra in the pelvis which would cause blood to pool in the pelvis area. If you tear the urethra in a strattle type injury then you are likely to tear the urethra in the spongy area and blood can pool pretty much everywhere if the buck’s fascia and colle’s fascia is torn

Question 20

Erectile bodies in female

Answer 20

• vestibular bulb - equivalent to the bulb of the penis?
• greater vestibular gland - equivalent to the bulbourethral gland. Will secrete liquid into the vestibule.
• crura of clitoris

Question 21

Skeletal muscle in superficial perineal pouch (female)

Answer 21

bulbospongeosus - compresses the vaginal opening
ischiocavernosus
superficial trasverse perineal muscle

Question 22

Contents of superficial perineal pouch in female

Answer 22

• erectile bodies
• skeletal muscle
• fascia
• blood vessels and nerves
• urethra and vagina (really this splits the pouch in half)
• greater vestibular gland

Question 23

perineal body

Answer 23

This is the central tendon of the perineum. Attached to it is the levator ani (pelvic diaphragm) as well as the external anal sphincter, bulbospongiosus, superficial transverse perineal muscles, fibers from the external urinary sphincter, deep transverse perineal muscle

Question 24

Blood supply and nerve supply to the perineum

Answer 24

Internal Pudendal artery
pudendal nerve (somatic) (S2, S3, S4)
Sympathetics - preganglionics from L1-L2, postganglionics from sacral paraverterbal ganglia
parasympathetics - preganglionics from pelvic splanchnic nerves (S2, S3, S4) and postganglionics from caverous nerves

Question 25

Venous drainage of pernieum

Answer 25

perineum - internal pudendal vein

erectile bodies - deep dorsal vein

Question 26

Urogenital Triangle

Answer 26

Connects from pubic symphasis to the ischial tuberosity

Question 27

Branches of the pudendal nerve

Answer 27

Inferior rectal - motor to external anal sphincter and levator ani
- sensory to ischioanal fossa
Dorsal nerve - sensory to the clitoris and dorsum of penis
perineal nerve - motor and sensory to all structures in the superficial and deep perineal pouches as well as some skin