Pelvis, Perineum & Reproductive Organs Flashcards
What is the pelvis?
The lowermost portion of the trunk and lies below the abdomen
abdomino-pelvic cavity
the cavities of both the abdomen and pelvis (which are continuous)
What structure closes the pelvic cavity inferiorly?
pelvic diaphragm or pelvic floor
What are the 2 joints of the pelvic girdle ?
- sacroiliac joint
2. pubic symphysis
sacrotuberous ligament
connects posterolateral border of sacrum with ischial tuberosity
sacrospinous ligament
connects anterolateral border of sacrum with ischial spine
Name 3 major pelvic foramina
- greater sciatic foramen
- lesser sciatic foramen
- obturator foramen
Where is the greater sciatic foramen located?
between the greater sciatic notch and the sacrospinous and sacrotuberous ligament.
Where is the lesser sciatic foramen located?
located between the lesser sciatic notch and both ligaments
Where is the obturator foramen ?
surrounded by the rami of the pubic and ischial bone and closed by the obturator membrane
What is the deepest cavity in women?
the rectouterine pouch
Where is the vesicouterine pouch?
anterior to the uterus
where is the rectovesical pouch located in men?
most caudal part of the abdomenpelvic cavity in men.
pelvic floor
musculofascial inferior closure of the abdominopelvic cavity and supports the position of viscera.
What 2 muscles make up the pelvic floor?
- levator ani
2. coccygeus
What 3 muscles make up the levator ani?
- puborectalis
- pubococcygeus
- illiococcygeus
from “inside” to outside: 1–>3
What is the action of the levator ani?
supports the pelvic viscera; raises pelvic floor
what is the action of the coccygeus?
supports pelvic viscera; draws coccyx forward
What the is the action of the piriformis?
rotates extended thigh laterally; abducts flexed thigh; stabilizes hip joint
The pelvic diaphragm maintains ________ through tonic contraction and relaxes during ________
- fecal and urinary continence
2. urination and defecation
levator hiatus
an anterior gap (a door) in the levator ani muscle that allows for the passage o the urethra, vagina and rectum
Where in the uterine tubes does fertilization occur?
in the ampulla
fundus
rounded superior part of body above oviducts, lies superior to the bladder
body
mobile part extending from cervix to fundus
cervix
communicates with vagina (external os) and with the uterine lumen (internal os)
endometrium
inner lining
myometrium
thick muscle layer
parametrium
surrounding connective tissue [perimetrium: peritoneal lining of funds and corpus]
infundibulum
fimbriated highly motile distal end that opens into the abdominal cavity; fimbriae move towards the ovulating surface of the ovary
ampulla
widest and longest part of fallopian tube
isthmus
thick-walled part that enters the uterus
uterine part
that traverses the uterine wall and opens into the uterine cavity
What connects the ovaries to the uterus?
ovarian ligament
How does the main blood supply from the abdominal aorta reach the ovary?
Through the suspensory ligament of the ovary: infundibulopelvic ligament. carries ovary blood and lymph vessels connecting the ovary to the retroperitoneal abdominal space
Broad ligament
- peritoneal fold reaching from the lateral pelvic wall to the uterus
- contains the uterine artery and vein and autonomous nerves
mesovarium and mesosalpinx
parts of the broad ligament reaching to ovary and uterine tube
suspensory ligament
carries ovarian blood and lymph vessels connecting the ovary to the retroperitoneal abdominal space
proper ligament of the ovary (ovarian ligament)
caudal connection to the uterus
describe the fallopian tube from the uterus to the ovary
- isthmus
- ampulla
- infundibulum
- fimbriae
round ligament of uterus
- courses within the broad ligament
- connects the fundus of the uterus through the inguinal canal to the labia major
What are the 4 functions of the fallopian tube?
- pick-up of ovulated oocytes
- transport of the maturating oocyte
- nourishment of oocyte and blastocyst
- sperm reservoir
function of the vagina
- forms the inferior part of the birth canal
- receives penis and ejaculate during sexual intercourse
function of ovary
- secretion of the steroid hormones estrogen (follicular granulosa cells) and progesterone (luteal cells of the corpus luteum)
- production of ova (ovarian follicles)
uterus
- harbouring and nourishing the embryo/fetus (endometrium and myometrium)
Pain sensation from the fundus and body of the uterus
travels along sympathetic nerve fibres (Th10-L1)
pain sensation of vagina and cervix uteri
travels along parasympathetic pathway (S2-S4) spinal sensory ganglia
The inferior part (lowest 5th) of vagina receives what kind of innervation?
somatic innervation through the perineal branch of the pudendal nerve
Which part of the fallopian tube is responsible for pick-up of ovulated oocytes?
infundibulum
What part of the fallopian tubes is responsible for transport of the maturating oocyte?
infundibulum and ampulla
Which part of the fallopian tube is responsible for nourishment of oocyte and blastocyst
ampulla
What part of the fallopian tube is the sperm reservoir?
isthmus
In the ovary, what kind of cells are responsible for secretion of the steroid hormone estrogen?
follicular granulosa cells
In the ovary, what kind of cells are responsible for secretion of the steroid hormone progesterone?
luteal cells of the corpus luteum
Where are the seminal vesicles located?
posterior to the bladder
What 2 structures join together to form the ejaculatory duct?
vas deferens & seminal vesicle
What sheath covers the epididymis and testis?
tunica vaginalis testis
Where are the testicular arteries derived and where do they course through?
Derived from from the abdominal aorta and traverse through the inguinal canal
What produces spermatozoa ?
tubuli seminiferi
what produces testosterone?
leydig cells
Where do the lymph vessels in the testis drain into?
they travel along the testicular vessels and drain into the pre-aortic lymph nodes (lumbar nodes)
What is the function of the rectum?
storage and controlled release of feces
Describe the rectum
- on the distal end of the large intestine
- rectal ampulla above the pelvic floor
- rectal ampulla transitions into anal canal
What arteries supply the rectum?
- superior rectal artery (from inferior mesenteric artery)
- middle rectal artery (from internal iliac artery)
- inferior rectal artery (from pudendal artery)
List the veins of the rectum. Trace them back to the inferior vena cava and portal vein
- superior rectal vein –> inferior mesenteric vein –> to portal vein
- middle rectal vein –> common iliac vein
- inferior rectal vein –> pudendal vein –> common iliac vein –> inferior vena cava
Name the anal sphincter muscles. What kind of muscles are they?
- internal anal sphincter - smooth muscle
2. external anal sphincter - skeletal muscle
how is voluntary closure of the anus achieved?
achieved by striated muscles of the anal sphincter apparatus
What innervates the external anal sphincter?
pudendal nerve
the internal anal sphincter is under sympathetic or parasympathetic control?
sympathetic; permanently contracted to close the anal canal
What does the INFERIOR GLUTEAL ARTERY supply?
- pelvic diaphragm
- gluteus maximus
- hamstrings
- quadratus femoris
Where does the INFERIOR GLUTEAL ARTERY branch off from? Where is it located?
- branches from the internal iliac artery (parietal branch) and courses through the greater sciatic foramen inferior to the piriformis muscle.
What does the SUPERIOR GLUTEAL ARTERY supply?
- gluteus medius
- gluteus minimus
- tensor fasciae lata
Where does the SUPERIOR GLUTEAL ARTERY branch off from? Where is it located?
- internal iliac artery (parietal branch)
2. runs between lumbosacral trunk and 1st sacral nerve above the piriformis muscle
What does the INTERNAL PUDENDAL ARTERY supply?
- supplies perineum (skin, muscles, erectile tissues)
Where does the INTERNAL PUDENDAL ARTERY branch off from? Where is it located?
- internal iliac artery (parietal branch)
2. branches off the interior rectal artery
what does the ILIOLUMBAR ARTERY supply?
- iliacus
- psoas
- quadratus lumborum muscle
LATERAL SACRAL ARTERY
branches enter the pelvic sacral foramina
What are the major parietal branches of the internal iliac artery?
- iliolumbar artery
- lateral sacral artery
- superior gluteal artery
- obturator artery
- internal pudendal artery
- inferior gluteal artery
OBTURATOR ARTERY
leaves through obturator foramen; supplies obturator muscles
What are the visceral branches of the internal iliac artery?
- umbilical artery
- superior and inferior vesical artery
- middle rectal artery
- uterine artery
umbilical artery
distal part obliterated as medial umbilical ligament, gives rise to sup. vesicle artery
What do the superior and inferior vesicle artery supply?
bladder and ureter, seminal vesicle and prostate (in men)
what does the middle rectal artery supply?
inferior rectum and seminal vesicles
where does the uterine artery arise from?
may arise from umbilical or directly from internal iliac artery
What nerve and artery supply the perineum?
- pudendal artery
2. pudendal nerve
The perineum is separated into a diamond shape. What are the two triangles called that make up this diamond?
- urogenital triangle
2. anal triangle
What are the contents of the urogenital triangle of the perineum?
- urogenital diaphragm
- urethra
- external genitalia
What are the contacts of the anal triangle of the perineum?
- anus and anal canal
2. ischioanal fossae
perineum
area inferior to the pelvic floor
the levator hiatus is a gap in the levator ani that allows for the passage of what structures?
- urethra
- vagina
- anal canal
What nerve innervates the muscles of the perineum?
the pudendal nerve
perineal membrane does what?
provides support in the area of the urogenital triangle
What is the root of the penis?
bulb of penis is covered by a scrotal raphe
What is contained within the scrotum?
- testis
- epididymis
- blood vessels
what innervates the scrotum?
anteriorly: branches from ilioinguinal and genitofemoral nerve
posteriorly: branches from pudendal nerve
sensory innervation is conveyed by what nerve to the penis?
pudendal nerve (S2-S4): dorsal nerve of the penis
what important artery in the penis arises from the internal pudendal artery?
deep penile artery
What is the structure that contain the corpora cavernosa?
tunica albuginea
What structure allows the urethra to remain open during erection?
corpus spongiosum
What causes an erection? What happens?
- parasympathetic stimulation (S2-S4) via pelvic splanchnic nerves
a) closes arteriovenous anastomoses
b) relaxes smooth muscles in helicine arteries (branches of deep artery of penis)
c) arterial blood flows into the cavernous spaces in corpora cavernosa
d) venous return is decreased by pressure in the tunica albuginea
what relaxes smooth muscles in helicane arteries?
inhibitors of cGMP-selective phosphodiesterase-type 5 (PDE5)
what causes emission and ejaculation? What happens before ejaculation? What happens during ejaculation?
- sympathetic stimulation (L1/L2)
before
a) stimulates peristalsis of ductus deference and seminal vesicles
b) semen and secretions delivered to prostatic urethra through ejaculatory ducts
during
a) semen is expelled from urethra
b) contraction of bulbospongiosus muscle (s2-s4, pudendal nerve)
c) closure of the internal urethral sphincter (vesicle sphincter)
ischioanal fossae
space beneath the pelvic diaphragm (pelvic floor)
what are some pathological conditions common in the perianal region?
- anal fissures and fistulas
2. peri-anal abscesses
What nerve innervates the perineum?
pudendal nerve (S2-S4)
Where does the pudendal nerve course?
- exits through the greater sciatic foramen
- winds around the ischial spine and sacrospinous ligament
- enters the pelvis again through the lesser sciatic foramen
- reaches the perineum below the pelvic diaphragm
the somatic motor nerve of the perineum goes to what muscles?
voluntary sphincter muscles: external urethral and anal sphincter
What is pudendal nerve block useful for?
useful to reduce the perineal pain associated with the second stage of labour or with episiotomy or the repair thereof
In pudendal nerve block, where is the anaesthesia effective? Where is it not effective?
- S2-S4 dermatomes and lower part of the vagina
- not effective for cervix and upper part of vagina
Where is pudendal nerve block administered?
near the ischial spine
Why may anesthesia of the pudendal nerve not eliminate all perineal pain?
Pudendal nerve only reaches posterior labial nerves and inferior rectal nerve but not other areas that are innervated by for example, the branch of the ilioinguinal nerve and the perineal branch of posterior cutaneous nerve of the thigh
