Pelvic Walls, Nerves, and Vasculature Flashcards
What makes up the pelvic floor?
-coccygeus, levator ani muscles (puborectalis, iliococcygeous, pubococcygeous)
and their fascias
-Perineal membrane (inferior fascia of UG diaphragm)
-muscles of deep perineal pouch
What is the perineal membrane?
inferior fascia of UG diaphragm
What separates the pelvic cavity from the perineum?
pelvic floor
What is the origin and insertion of the coccyeous muscle?
(origin) the ischial spine and the sacrospinous ligament
(insertion) to coccyx and inferior sacrum
What is the function of the coccygeous muscle?
supports pelvic viscera, pulls coccyx forward after defecation
The levator ani consists of three paired muscles, what are they?
puborectalis
iliococcygeus
pubococcygeus
What is the puborectalis and where does it arise from?
arises from right and left pubic bodies
U-shaped sling
Where does the pubococcygeus arise from and attach to?
from posterior part of pubic body and anterior tendinous arch and
attaches at coccyx
The pubococcygeus is divided into several sections which were….?
pubovaginalis
puboprostaticus
puboanalis
The iliococcygeus muscle arises from the (blank)
posterior tendinous arch and ischial spine
The iliococcygeous forms a ligament/raphe between what 2 things?
the anal aperature and the coccyx
Is the iliococcygeous muscle thick?
no it is thin and poorly developed
What is the importance of the levator ani?
for support, continence, as a vaginal sphincter, defecation and urination
What is the innervation to the levator ani?
Direct branches from ventral rami of S4 and inferior rectal branch of pudendal nerve (S2-S4)
What muscles insert at the perineal body?
bublospongiosus muscle, sup. transverse perineal muscle, pubococcyeus mucsle, external anal sphincter muscle
Other than the main muscles that insert at the perineal body, what are some additional fibers that insert there?
deep transverse perineus
external urethral sphincter
puborectalis
What is the clinical relevance of knowing the muscles that insert at the perineal body?
episiotomy
The common iliac splits into the internal and external iliacs at the level of the IV disc between (blank and blank)
L5 and S1
The internal iliac splits into what?
the anterior and posterior divisions
What supplies the pelvic viscera, walls, floors, perineal structure, gluteal region and thigh with blood?
anterior and posterior branches of internal iliac
Besides the anterior and posterior branches of the internal iliac, what also supplies the pelvic region?
gonadel artery (from aorta)
median sacral artery (from aorta)
superior rectal artery (from IMA)
The internal iliac’s anterior branch,branches into what 8 arteries?
umbilical -> superior vesical artery obturator inferior vesical (males) vaginal (female) middle rectal uterine (or artery to ductus deferens) internal pudendal inferior gluteal
The posterior branch of the internal illiac branches into what 3 arteries?
iliolumbar
lateral sacral
superior gluteal
The internal iliac’s anterior branch,branches into what 8 arteries?
umbilical-> superior vesical artery obturator inferior vesical (males) vaginal (female) middle rectal uterine (or artery to ductus deferens) internal pudendal inferior gluteal
The posterior branch of the internal illiac branches into what 3 arteries?
iliolumbar
lateral sacral
superior gluteal
(blank) is the first branch of the anterior trunk of internal illiac and gives rise to the superior vesical artery.
umbilical artery
What does the umbilical artery turn into?
the superior vesical artery
What happens after birth to the umbilical artery?
it becomes a solid fibrous cord and creates a medial umbilical fold and medial umbilical ligament
What does the superior vesical artery supply?
supplies superior bladder and distal ureter
What often comes off the superior vesical artery?
artery of the ductus deferens
What is this:
It usually is the second branch off of the anterior trunk of the internal illiac. It runs along obturator fascia on the lateral wall of the pelvis and leaves the pelvis through the obturator canal.
Obturator artery
What does the obturator artery supply?
the adductor region of the thigh
Where does the obturator artery run?
it runs along the obturator fascia on the lateral wall of the pelvis
What is a common variation of the obturator artery?
presence of an accessory obturator artery arising from inferior epigastric artery and descending the normal path of the main branch
Why is it important to know the variations of the obturator artery?
important for hernia repair surgeries
What artery is the equivalent to the vaginal artery in the male?
inferior vesical artery
What does the inferior vesical artery supply?
supplies the bladder, distal ureter, seminal vesicles (male)
What does the vaginal artery supply?
supplies the vagina, bladder and rectum and anastomoses with the uterine artery and superior vesical artery
What supplies the inferior rectum where it anastomoses with the superior and inferior rectal arteries and the seminal glands and prostate or vagina?
middle rectal artery
Where does the middle rectal artery arise from?
Either from the internal iliac artery
or in common with the inferior vesicle artery or
internal pudendal artery
What does the middle rectal artery spply?
supplies,
inferior rectum, seminal glands, prostate or vagina
Where do we find the uterine artery?
within the cardinal ligament and arises from the umbilical artery (usually)
Does the uterine artery pass under or over the ureter?
over
The uterine artery is homologous to what?
to the artery to the ductus deferens
The umbilical artery divides into branches that supply what?
A branch that supplies the vagina and cervix
A branch that supplies the body and fundus of the uterus
The uterine artery anastomoses with what?
the ovarian artery
What is enlarged during pregnancy?
the uterine artery
What all does the uterine artery supply?
the utereus, the ovary, ovarian tubes
Explain the path of the internal pudendal artery.
leaves the pelvis through the greater sciatic foramen and enters the ischioanal fossa via the lesser sciatic foramen with the pudendal nerve and passes through the pudendal canal
The internal pudendal artery divides into what?
deep and dorsal branches of the clitoris or penis as it exits the pudendal canal.
What is the main artery of the perineum?
internal pudendal artery
Explain the path of the inferior gluteal artery
passes posteriorly between the sacral nerves and leaves the pelvis though the greater sciatic foramen (inf. to piriformis).
What does the inferior gluteal artery supply?
the muscles and skin of the buttock and posterior thigh
What does the inferior gluteal artery anastomose with?
a network of vessels around the hip joint
What is the largest branch of the internal iliac artery?
superior gluteal artery
What is the terminal continuation of the posterior division of the internal illiac?
the superior gluteal artery
How does the superior gluteal artery pass through the pelvic cavity?
Courses posteriorly and between nerves of the lumbosacral trunk and S1, leaves the pelvis through the greater sciatic foramen (superior to piriformis).
What does the superior gluteal artery supply?
supplies the muscles and skin of the gluteal region as well as supplying branches to adjacent muscles and bones of the pelvic wall
What is the path the iliolumbar artery takes?
ascends laterally back out of the pelvic inlet and divides
What does the iliolumbar artery branch into?
the iliac branch and the lumbar branch
What branch of the iliolumbar passes laterally into the iliac fossa (supplies the iliacus and ilium)
iliac branch
What branch of the iliolumbar supplies the posterior abdominal wall, the cauda equina, the psoas major and quadratus lumborum muscles?
lumbar branch
What does the iliac branch of the iliolumbar artery supply?
supplies the iliacus and ilium
What does the lumbar branch of the iliolumbar artery supply?
supplies the posterior abdominal wall, the psoas muscle and quadratus lmborm and the cauda equina
What is this: Usually two (superior and inferior) arteries on each side arising from a the posterior trunk of the internal illiac
lateral sacral arteries
What gives off spinal branches which supply the sacral meninges enclosing the roots of the sacral nerves?
lateral sacral arteries
What do the lateral sacral arteries supply?
supply the erector spinae muscles and skin covering the sacrum
What do the spinal branches off of the lateral sacral arteries supply?
supplies the sacral meninges and encloses roots of sacral nerves
There is collateral circulation to the posterior abdominal and pelvic wall and spinal cord, how is this achieved?
lumbar (abdominal aorta) and iliolumbar arteries (posterior trunk of internal iliac)
There is collateral circulation to the back and spinal cord, how is this achieved?
median sacral (abdominal aorta) and lateral sacral (iliolumbar /posterior trunk of internal iliac)
There is collateral circulation to the rectum, how is this achieved?
superior rectal (IMA) and middle rectal (anterior division of internal iliac)
There is a collateral circulation to the gluteal muscles and hip joint, how is this achieved?
inferior gluteal artery (anterior division of internal iliac) and deep artery of the thigh (femoral artery)
What happens if you blockage of right internal iliac and left internal iliac?
you will get Leriche syndrome which will result in impotence and (claudation) loss of sensation in buttocks and thighs
There is collateral circulation to the posterior abdominal and pelvic wall and spinal cord, how is this achieved?
lumbar (abdominal aorta) and iliolumbar arteries (posterior trunk of internal iliac)
There is collateral circulation to the back and spinal cord, how is this achieved?
median sacral (abdominal aorta) and lateral sacral (iliolumbar /posterior trunk of internal iliac)
There is collateral circulation to the rectum, how is this achieved?
superior rectal (IMA) and middle rectal (anterior division of internal iliac)
There is a collateral circulation to the gluteal muscles and hip joint, how is this achieved?
inferior gluteal artery (anterior division of internal iliac) and deep artery of the thigh (femoral artery)
What happens if you blockage of right internal iliac andleft internal iliac?
you will get Leriche syndrome which will result in impotence and (claudation) loss of sensation in buttocks and thighs
There is collateral circulation to the posterior abdominal and pelvic wall and spinal cord, how is this achieved?
lumbar (abdominal aorta) and iliolumbar arteries (posterior trunk of internal iliac)
There is collateral circulation to the back and spinal cord, how is this achieved?
median sacral (abdominal aorta) and lateral sacral (iliolumbar /posterior trunk of internal iliac)
There is collateral circulation to the rectum, how is this achieved?
superior rectal (IMA) and middle rectal (anterior division of internal iliac)
There is a collateral circulation to the gluteal muscles and hip joint, how is this achieved?
inferior gluteal artery (anterior division of internal iliac) and deep artery of the thigh (femoral artery)
What happens if you blockage of right internal iliac andleft internal iliac?
you will get Leriche syndrome which will result in impotence and (claudation) loss of sensation in buttocks and thighs
Pelvic veins follow the course of all internal iliac artery branches except for the (balnk) arteries.
umbilical artery, iliolumbar artery and some of the internal pudendal artery (i.e deep dorsal vein).
In the pelvis, the veins all drain into the (blank) which drain into the (blank)
internal iliac veins
common iliac veins
Where are there extensive interconnected venous plexuses?
around the bladder, rectum, prostate, uterus, vagina which collectively form the pelvic plexus of veins
The venous plexus surrounding rectum and anal canal drains via (blank) and (blank).
Superior rectal veins
middle and inferior rectal veins
Where do superior rectal veins drain into?
into IMV so into the hepatic portal system
Where do middle and inferior rectal veins drain into?
into internal illiac and common iliac so into the caval system
Why is it important the the rectal veins have different ways of drainage?
This is called the portal-caval shunt and it is important because if you have blockage of one vein you will still have venous drainage
The inferior part of the rectal plexus around anal canal has 2 parts, which are?
internal rectal plexus and external venous plexus
The (blank) that drains the erectile tissue of the penis and clitoris passes directly into the pelvic cavity.
deep dorsal vein
What does the deep dorsal vein join with ?
the prostatic or vesical venous plexuses
Ovarian veins on the left join the (blank)
renal vein
On the right, the ovarian veins join the (blank)
IVC
How does the lymphatic drainage work in the pelvis?
it follows the venous drainage therefore most drainage via internal iliac nodes
What lymphatic nodes drain this:
perineum (skin, penis, scrotum and vulva), uterus (area of round ligament), lower limb, gluteal region, anal canal (below pectinate line), vagina (external orifice)
superficial inguinal nodes
What lymphatic nodes drain this:
perineum (clitoris and glans penis, distal spongy urethra)
Deep inguinal nodes
What lymphatic nodes drain this:
anterosuperior pelvic viscera
External iliac nodes
What lymphatic nodes drain this:
most pelvic viscera (inferior aspects), anal canal (above pectinate line), deep perineal strucutres (vagina, urethra), inferior rectum, prostate
internal iliac nodes
What are some minor nodes?
sacral and pararectal
What lymphatic nodes drain this:
gonads
lumbar nodes
How does drainage of lymphatics occur?
drainage into common iliac nodes, then lumbar trunks, ultimately into cisterna chylli
Where does the inferior gluteal nerve come from?
L5-S2 nerves
Where do the lumbosacral trunk, sciatic nerve, pudendal nerve, superior gluteal nerve, inferior gluteal nerve all leave the pelvis through?
from the sacral plexus and leave pelvis via greater sciatic foramen
What two muscles form a bed for sacral and coccygeal nerves?
the piriformis and coccygeus muscles
The piriformis and coccygeus muscles form a bed for (blank and blank) nerves.
sacral and coccygeal nerves
(blank) primarily innervate the lower limb and perineum.
somatic nerves
(blank) passes through the lesser pelvis passing through the obturator membrane and innervates the medial thigh (does not innervate the actual pelvis).
obturator nerve (L2-L4)
Explain how the lumbosacral trunk starts
The lumbosacral trunk comprised of the anterior division of the fifth and a part of the fourth lumbar nerve; it appears at the medial margin of the psoas major and runs downward over the pelvic brim to join the first sacral nerve.
Where does the sciatic nerve come from?
L4-S3 (passes through but does not innervate the pelvis)
Where does the pudendal nerve come from?
S2-S4
Where does the superior gluteal nerve come from?
L4-S1
Where does the inferior gluteal nerve come from?
L5-S2 nerves from the sacral plexus and leave pelvis via greater sciatic foramen
Where do the lumbosacral trunk, sciatic nerve, pudendal nerve, superior gluteal nerve, inferior gluteal nerve all leave the pelvis through?
from the sacral plexus and leave pelvis via greater sciatic foramen
(blank) is the main nerve of the perineum and the chief sensory nerve to the external genitalia
pudendal nerve
How does the pudenedal nerve travel through the pelvis?
out of the pelvis via greater sciatic foramen and into the perineum via the lesser sciatic foramen
What do the terminal branches of the pudendal nerve innervate?
innervates the exerternal urethra sphincter, external anal sphincter, sensory to external genitalia and skin surrounding the anus and perineum
Tell me about the coccygeal plexus
lies on the pelvic surface of the coccygeus
innervates coccygeus and part of levator ani
What nerves arise from the coccygeal plexus?
anococcygeal nerves
What is the main function of the periarterial plexus?
vasomotion of the arteries they accompany
What do the parasympathetic pelvic autonomic nerves do?
vasodilation leading to erection
bladder contraction
contraction of rectum
modulation of ENS (the part not innervated by the vagus)
(causing peeing, and defecation, erection)
Autonomic nerves enter the pelvic cavity via four main routes, what are they?
1) Sacral sympathetic trunks
2) Periarterial plexuses
3) Hypogastric plexuses:
- Superior hypogastric plexus
- Inferior hypogastric plexus
4) Pelvic splanchnic nerves
Autonomic nerves enter the pelvic cavity via four main routes, what are they?
1) sacral sympathetic trunks
2) periarterial plexuses
3) hypogastric plexuses
4) pelvic splachnics
What is the sacral sympathetic trunk?
it is the continuation of the lumbar sympathetic trunk to innervate the lower limbs
What does the sacral sympathetic trunk do?
sends grey communicating rami to each anterior ramus of sacral and coccygeal nerves
sends small branches to inferior hypogastric plexus (sacral splachnics)
What is the main function of the sacral sympathetic trunk?
provides postsynaptic fibers to the sacral plexus for sympathetic innervation of the lower limb
(contributes to only 10% of sympathetic innervation)
What kind of fibers are in the periarterial plexuses?
postsynaptic, sympathetic, vasomotor fibers
Where do the fibers of the periarterial plexus go?
go to the superior rectal, ovarian and internal iliac arteries and their branches
Is the periarterial plexus the major route for sympathetic fibers to enter the pelvis?
No, it is a minor route
What is the main function of the periarterial plexus?
vasomotion of the arteries they accompany
What is the most important route by which sympathetic fibers are conveyed to pelvic viscera?
hypogastric plexuses
What kind of fibers are wtihin the hypogastric plexus?
networks of sympathetic, parasympathetic, and visceral afferent nerve fibers
There are 2 hypogastric plexuses?
superior and inferior
What is made up of the continuation of the aortic plexus, branches off the L3, L4 and lumbar splachnics (sympathetic)?
superior hypogastric plexus
Explain how superior hypogastric plexus turns into the inferior hypogastric plexus
superior hypogastric plexus divides into right and left hypogastric nerves once it enters the pelvis, they descend laterally to the rectum andthen converge with pelvic splachnics and forms the left and right inferior hypogastric plexuses.
How do parasympathetic fibers get to the superior hypogastric plexus?
through right and left hypogastric nerves
How do you get to the inferior hypogastric plexus?
the right and left hypogastric nerves join together withpelvic splachnics and sacral splachnics
The hypogastric plexus contains what kind of fibers?
postganglionic sympathetic and preganglionic parasympathetic fibers as well as visceral afferent fibers
(blank) form sub-plexuses known as pelvic plexuses (middle rectal, uterovaginal, vesical, prostate) which travel with appropriate branches of the internal iliac artery to target organ.
Inferior hypogastric plexus
Terminal branches of the inferior hypogastric plexus will penetrate and pass through the (blank) innervate erectile tissues (release NO)
deep perineal pouch
Where do pelvic splachnics originate?
from the anterior rami of S2-S4
What do pelvic splachnics do?
convey presynaptic parasympathetic fibers
(blank) join the hypogastric nerves to form the inferior hypogastric plexus and also supply the superior hypogastric plexus.
Pelvic splachnics
How do you get parasympathetic innervation of the pelvic viscera and descending and sigmoid colon?
via the pelvic splachnics
Visceral afferent fibers travel with (blank)
autonomic nerves
How do visceral afferent fibers travel?
they follow the course of sympathetic and parasympathetic fibers in the pelvis.
The course of pain fibers depends upon whether the pain is arising from above or below the (blank)
pelvic pain line
The pelvic pain line refers to organs being above (or in contact with) or below the (blank)
peritoneum
Superior to the pain line, how do visceral afferents travel?
follow sympathetic fibers and reach cell bodies in inferior thoracic/upper lumbar spinal ganglia (only true for the pelvis!)
Inferior to the pain line, how do visceral afferents travel?
follow parasympathetic fibers to reach cell bodies in spinal sensory ganglia of S2-4
What is the only exception to the pain line rule?
large intestine, the pelvic pain line is located in the middle of the sigmoid colon.
T or F
Pain from below the pain line is less likely to be felt consciously
T
Explain how males get an erection.
parasympathetics (pelvic splachinics S2-4)
make dilation and straightening of helicine arteries and engorgement of corpus cavernosum and contraction of bulbospongiosus and ischiocavernosus muscles and traps blood
Explain how males have emission.
sympathetic nerves L1-L2
Sperm and other secretions released in prostatic urethra, contraction of ductus deferens, seminal glands and prostate
Contraction of internal urethral sphincter
Explain male ejaculation.
Somatomotor (S2-S4), Sympathetic
somatomotor: Contraction of bulbospongiosus, levator ani, EAS, gluteal muscles
sympathetic: Propulsion of semen along the penile urethra
Explain male remission
(detumescence/resolution) – Sympathetic
Vasoconstriction and recoil of helicine arteries, flaccid
Relaxation of bulbospongiosus and ischiocavernosus muscles, drainage of blood into deep dorsal vein
Refractory period
Explain female arousal
Parasympathetic (Pelvic splanchnic nerves, S2-S4)
Increased vestibular and vaginal secretions
Erection of clitoris (similar mechanism to erection of the penis)
Explain female plateau
(lasts minutes to hours) – Sympathetic (L1-L2 nerves)
Vascular engorgement (clitoris, labia, breasts, lower vagina)
Erection of nipples
Sex flush (reddening of chest)
Dilation of upper vagina
Tenting of the uterus (lengthening of vagina)
Explain female orgasm
Somatomotor (S2-S4), Sympathetic
Contraction of bulbospongiosus, ischiocavernous (~1 second intervals, variable)
Dilation of cervix
Uterine contractions (oxytocin)
Dipping of the uterus (shortening of vagina)
Explain female resolution
(detumescence) – Sympathetic
Return of pre-arousal stage
Relaxation of bulbospongiosus and ischiocavernosus muscles, drainage of blood into deep dorsal vein
No refractory period
