Pelvic Vasculature and Perineum

Question 1

Anterior Division of the Internal Iliac Artery

Answer 1

1. Obturator Artery (can arise from inferior epigastric; important to remember when repairing hernia
2. Umbilical Artery (gives off some superior vesical arteries; obliterated distal part =medial umbilical ligament)
3. Inferior vesical artery
4. Middle rectal artery
5. (F) Vaginal and uterine artery (must ligate during hysterectomy)
6. Inferior gluteal artery
7. Internal pudendal artery
   * Focus on where vessels are going as there is much variation

Question 2

Uterine Artery

Answer 2

Passes OVER the ureter; must remember to ligate during ovariectomy

Question 3

Internal Pudendal Artery

Answer 3

Travels out the greater sciatic foramen and back thru the lesser to supply perineal structures

*If it traveled thru the pelvic diaphragm, it could cause a potential site for herniation of pelvic organs

Question 4

Posterior branches of Internal Illiac

Answer 4

1. Iliolumbar artery
2. Lateral sacral artery
3. Superior gluteal artery

Question 5

Inferior rectal nerve

Answer 5

Branch of the internal pudendal nerve that innervates the external anal sphincter and provides somatosensory to the bottom 1/2 of the anal canal

*Other branches of internal pudendal also include the dorsal nerve of the penis/clitoris and the scrotal/labial nerves

Question 6

Beginning of anal canal

Answer 6

Coccyx

Question 7

Internal Anal Sphincter

Answer 7

Parasympathetic stimulation for the splanchnic nerves causes relaxation of the sphincter

Question 8

External anal sphincter

Answer 8

Somatic innervation from the pudendal nerve and contains three subgroups: 1. Deep part

                2. Superficial part
                3. Subcutaneous part

Question 9

Anorectal ring

Answer 9

Composed of deep part of external anal sphincter, puborectalis, and internal anal sphincter

*Palpable during exam

Question 10

Anal columns

Answer 10

Fold of mucosal membrane; contain the portal caval anastomoses

Question 11

Anal valves

Answer 11

Epithelial folds indicating the site of the pectinate line

Question 12

External hemorrhoids

Answer 12

Varicoses of the inferior rectal veins; very painful since lower half of anal column is somatosensory

Question 13

Perianal abscess

Answer 13

Infection in the ischiorectal fossa that typically stems from torn anal valves or a fistula; can travel from side to side and anteriorly to affect urogenital structures

Question 14

Urogenital Diaphragm

Answer 14

Lies inferior to the pelvic diaphragm and prevents herniation of prostate, uterus, and bladder thru the pelvic diaphragm

-Connected to inferior ramus and ischium

Question 15

Deep perineal pouch

Answer 15

Consists of striated muscles (deep transverse perineal muscle and sphincter urethrae) and bulbourethral glands (M)

-Also contains the pudendal NAV

Question 16

Deep transverse perineal muscle

Answer 16

Stabilizes the perineal body and reinforces the pelvic diaphragm

*Middle-layer muscle

Question 17

Sphincter urethrae

Answer 17

Voluntary muscle that relaxes during microtuition; also fnxns during ejaculation

*Middle-layer muscle

Question 18

Membranous urethrae

Answer 18

Found in the UGD; thinnest part of the urethra most susceptible to tearing, especially during catheterization

Question 19

Bulbourethral glands

Answer 19

Found in the UGD; secretes lubricant during sexual arousal into the penile (spongy) area of the urethra

Question 20

Superficial Perineal Pouch

Answer 20

Found inferior to the inferior fascial layer of the UGD and superior to the superior perineal fascia

Contains the superficial transverse perineal muscle, the erectile tissues (Crura and bulb), the internal pudendal NAV, and the bulbospongiosus and ischiocavernosus

Question 21

Superficial perineal fascia

Answer 21

Colle’s Fascia-a continuation of Scarpa’s fascia; attaches posteriorly to the perineal body and laterally to the ischiopubic rami

*Continues in the scrotum as the Dartos muscle

Question 22

Damage to perineum

Answer 22

Often causes urethral rupture @ the 90 degree angle where it enters the UGD

=>Urine enters superficial perineal pouch and anterior abdomen

• CANNOT enter ischiorectal Fossa or thigh due to posterior attachment of perineal membrane to UGD and lateral attachment of perineal membrane to the ischiopubic rami
• Can be caused by landing badly on top of fence

Question 23

Muscles of superficial perineal pouch

Answer 23

1. Superficial transverse perineal muscle
2. Bulbospongiosus-aids the emptying of the urethra; compresses blood vessels during erection
3. Ischiocavernosus muscles- aids in erection by compressing crus of penis

Question 24

Root of penis

Answer 24

Composed of the crus and bulb of the penis; firmly attached to the inferior fascial layer of the perineal membrane

Question 25

Suspensory ligament of penis

Answer 25

Originates at pubic symphysis and attaches to the tissue of the penis

Question 26

Buck's Fascia

Answer 26

Located deep to the superficial dorsal vein of the penis and envelops the deep dorsal veins and arteries of the penis

Question 27

Tunica albuginea

Answer 27

White CT that invests the corpus cavernosa and forms a septum b/w the two

Question 28

Dorsal artery of the penis

Answer 28

Supplies the skin of the penis and the surrounding erectile tissues

Question 29

Penis lymphatics

Answer 29

Skin => Superficial inguinal nodes Deep structures => Internal iliac nodes

Question 30

Erection

Answer 30

Parasympathetics relax dorsal artery of the penis and artery of the bulb to engorge the penis w/ blood *Veins are compressed by bulbospongiosus and ischiocavernosus

Question 31

Ejaculation

Answer 31

Smooth muscle contraction of ductus deferens, seminal vesicle, and prostate gland to eject secretions; pudendal nerve activates bulbospongiosus *Point and Shoot

Question 32

Crura of clitoris

Answer 32

Paired erectile tissues that become the body of the clitoris anteriorly

Question 33

Bulbs of vestibule

Answer 33

Split into two halves by the opening of the vagina; unite anteriorly as the glans clitoris

Question 34

Greater Vestibular Glands

Answer 34

Analogous to bulbourethral glands; secrete lubricant *Often become blocked and infected => cysts

Question 35

Mons pubis

Answer 35

Mass anterior to the pubic symphysis covered w/ fat and hair

Question 36

Frenulum

Answer 36

Point where the labia minora unites posteriorly *Anterior point is the prepuce of the clitoris

Question 37

Sensory innervation of the clitoris

Answer 37

Somatosensory nerves provided by dorsal nerve of the clitoris (from internal pudendal)

Question 38

Episiotomy

Answer 38

Surgical incision into posterior wall of the vagina to prevent tearing of the perineal body during childbirth; surgical repair of this incision to the perineal body is much easier to repair *Mediolateral incisions are more common because median incisions could damage the anorectal sphincter

Question 39

Pudendal Nerve Block

Answer 39

Physician locates the ischial spine usually thru a transvaginal approach and injects anesthetic thru the vaginal wall and sacrospinous ligament to relax the pudendal nerve *Performed to anesthetize the perineum prior to an episiotomy

Question 40

Inferior rectal artery

Answer 40

Branch of the internal pudendal artery that supplies the lower 1/2 of the anal canal

Question 41

Ischiorectal Fossa

Answer 41

Triangle formed by the skin, Obturator internus, and pelvic diaphragm -Contains mostly fat but also the pudendal NAV bundle in the Obturator internus fascia and the external anal sphincter

Question 42

Innervation of upper 1/2 of anal canal

Answer 42

Visceral sensory to the inferior hypogastric plexus

Question 43

Crura of penis

Answer 43

Attached to perineal membrane and ischiopubic ramus -erectile tissue

Question 44

Navicular Fossa

Answer 44

Widening of the male urethra at the glans of the penis

Question 45

Deep dorsal vein and vein to the bulb drainage

Answer 45

Prostatic venous plexus