Anatomy Flashcards
Why is it less common for children to get pelvic fractures than adults?
3 hip bones do not fuse together until puberty - held together by cartilage
What is the dividing line between ABD and pelvis?
pelvic brim
What space makes up the lesser (true) pelvis? What is found above it?
- space between the pelvic brim and the pelvic floor/diaphragm
- above it is the greater (false) pelvis that still contains ABD viscera
What contributes to the pelvic brim?
- arcuate line of the ilium
- pectin pubis
What attaches to the pubic tubercle?
inguinal L. - from ASIS to pubic tubercle
What is the opening at the pelvic brim called? What is found below it?
- opening at pelvic brim = pelvic inlet
- pelvic outlet found below it
Describe general structure of male and female pelvis
Male - thick and heavy
Female - thin and light
Describe greater and lesser pelvis of males and females
Male - narrow and deep greater/lesser pelvis
Female - wide and shallow greater/lesser pelvis
What is the shape of the pelvic inlet in males and females?
Male - heart-shaped and narrow
Female - oval/rounded and wide
What is the pubic arch and subpubic angle in males and females?
Male - narrow arch (< 70)
Female - wide arch ( > 80)
What is the shape of the obturator foramen in males and females?
Male - round
Female - oval
Who has a larger acetabulum: males or females?
males
What is the degree of the greater sciatic notch in males and females?
Male - narrow (70)
Female - almost 90
What part of the pelvis is likely to fracture from anterior-posterior compression?
pubic rami
What part of the pelvis is likely to fracture from lateral compression?
acetabulum and ilum
Name the 4 weak areas of the pelvis?
- pubic rami
- acetabulum
- SI joint
- iliac ala (wings)
What is L5 spondylolysis?
separation of the vertebral arch from vertebral body
What is L5 spondylolisthesis?
abnormal anteriorly directed separation of the L5 vertebral segment from the sacrum
Describe the locations of the iliolumbar L. and lumbosacral L.?
- iliolumbar L. - L5 TP to iliac crest
- lumbosacral L. - L5 TP to sacral ala
What makes up the greater and lesser sciatic foramen?
sacrospinous L. (greater) and sacrotuberous L. (lesser)
What is the action of the obturator internus M. and piriformis M.? Where do they both attach?
- laterally rotate the thigh (external rotation)
- both attached to greater trochanter of femur
What is the function of the coccygeus M.?
supports pelvic viscera and supports coccyx (keeps it in flexion)
Name 2 pelvic wall muscles
obturator internus M. and piriformis M.
Name 4 pelvic floor (diaphragm) Ms.
- coccygeus M.
- iliococcygeus M.
- pubococcygeus M.
- puborectalis M.
What 3 muscles make up the levator ani? Where are the located in relation to each other?
- iliococcygeus M. - most lateral
- pubococcygeus M. - middle
- puborectalis M. - most medial
What 2 muscles are at risk of tearing during childbirth?
pubococcygeus M. and puborectalis M.
What is the tendinous arch of the elevator ani? What does it divide?
- thickening of obturator internus fascia between ischial spine and pubic body
- divides obturator internus into superior and inferior regions
What are the 2 openings created by pelvic floor muscles called and what passes through them?
- levator hiatus
- rectum, urethra, and vagina (female)
What is an important function of the puborectalis M.?
- helps maintain fecal continence - relaxes during urination/defecation
- works independent of GI sphincters
What is the anorectal flexure?
encirclement of the rectum by levator ani (important for fecal continence)
Describe each of the following: anal column, anal valves, anal sinuses
- anal column - longitudinal ridges in anal canal
- anal valves - folds at base of anal columns
- anal sinuses - adjacent to the valves (secrete mucus to help w/ defecation)
Where are the internal/external anal sphincters located in relation to each other?
- internal = more medial
- external = more lateral
What type of muscle makes up the internal/external anal sphincters? Are they voluntary/involuntary?
- internal = smooth muscle; involuntary
- external = skeletal muscle; voluntary
Which anal sphincter makes up the majority of the resting sphincter tone?
internal (70-85%)
What divides the anal canal into 2 regions? What is the embryologic origin of each region?
- pectinate line
- above the line (upper 2/3) = endoderm
- below the line (lower 1/3) = ectoderm
What is the innervation of the superior/inferior anal canal?
- superior: inferior hypogastric plexus (visceral innervation)
- inferior: inferior rectal N. (from pudendal N.) - somatic innervation
What is the blood supply (artery) of the superior/inferior anal canal?
- superior: superior rectal A (from IMA)
- inferior: inferior rectal A. (from internal iliac A. -> internal pudendal A.)
What is the venous drainage of the superior/inferior anal canal?
- superior: superior rectal V. (IMV -> portal)
- inferior: inferior rectal V. (systemic: internal pudendal -> internal iliac -> common iliac -> IVC)
What is the lymphatic drainage of the superior/inferior anal canal?
- superior: internal iliac nodes -> inferior mesenteric nodes
- inferior: superficial inguinal nodes
What is the cause of internal hemorrhoids? What is seen with them? Are they painful?
- prolapsed rectal mucosa due to weakened muscular mucosae - usually due to portal HTN
- usually see bright red blood
- visceral innervation (not painful)
What is the cause of external hemorrhoids? Are they painful?
- external venous plexus covered w/ epidermis
- increased pressure causes dilated veins to rupture
- somatic innervation (painful)
What supplies lymph drainage to the superior/inferior rectum?
- superior: pararectal nodes -> sacral nodes
- inferior: internal iliac nodes
Where is the pelvic pain line located? What carries afferent info to the CNS above and below the pelvic pain line?
- located at the inferior limit of the peritoneum in pelvic cavity
- above the line = sympathetics (T12-L2)
- below the line = parasympathetics (S2-S4)
What is the deepest portion of the male and female peritoneal cavities? Why are these spaces important?
- Male: rectovesical pouch (between rectum and bladder)
- Female: rectouterine pouch (between rectum and uterus)
- spaces where ABD fluid collects; likely to develop abscesses here
Describe each of the following: supravesical fossa, paravesical fossa, pararectal fossa
- supravesical fossa: peritoneum on superior surface of bladder between median and medial umbilical folds
- paravesical fossa: depressions on either side of bladder
- pararectal fossa: pouches on either side of rectum
Describe each of the following: retropubic space and retrorectal space
- retropubic space: between bladder and pubic bone
- retrorectal space: between rectum and sacrum
What prevents you from putting your hand down between the pubic bone and the prostate/bladder in males? What is similar in females?
- puboprostatic L. in males
- pubovesical L. in females
What artery supplies the top of the bladder and where does it come from? Where is this artery found?
- superior vesical A. -> comes from patent umbilical A.
- found within the lateral L. of the bladder
Name 2 ligaments that help support the bladder
pubovesical L. and lateral L. of the bladder
What is the thickened fascia between the lateral vagina and tendinous arch of levator ani called?
paracolpium
At what angle do the ureters enter the bladder and what does this allow?
enter bladder at an inferomedial angle - allows pressure of bladder filling to clamp the ureters shut and prevent back flow of urine
Are the kidneys and ureters peritoneal or retroperitoneal?
retroperitoneal
What do the ureters run inferior to in males and females?
males: inferior to vas deferens
females: inferior to uterine A. (A. wraps around ureter)
What 4 arteries help supply the ureters?
- renal A.
- gonadal A.
- ABD aorta
- common/internal iliac As.
Name 3 nerves that innervate the ureters
- prearotic plexus
- hypogastric plexus
- pelvic splanchnic N. (parasympathetic)
What is connected to the apex of the bladder?
median umbilical L. (originally the urachus)
What type of epithelium are the ureters and bladder lined with?
transitional epithelium
What is the trigone of the bladder?
inferior/posterior wall where ureters and urethra open
What is the name of the smooth muscle lining the bladder wall?
detrusor M.
What type of muscle fibers make up the internal/external urethral sphincters?
internal: smooth muscle (continuous w/ detrusor M.)
external: skeletal muscle
Where are the internal/external urethral sphincters primarily located?
- mainly in the membranous urethra
- internal is continuous w/ bladder wall
- external is considered part of pelvic floor
What is the innervation of the internal/external urethral sphincters?
- internal: inferior hypogastric plexus; involuntary
- external: deep perineal branch of pudendal N.; voluntary)
What are the 3 regions of the male urethra? Which is the longest?
- prostatic urethra (passes through prostate)
- membranous urethra (contains sphincters)
- spongy/penile urethra (longest)
Define each of the following: urethral crest, prostatic sinuses, seminal colliculus, prostatic utricle.
- urethral crest: ridge in the prostatic urethra (thin on either end)
- prostatic sinuses: holes on either side of ridge where prostate gland secretes prostatic fluid
- seminal colliculus: enlarged portion of crest where 2 ejaculatory ducts open
- prostatic utricle: remnant of paramesonephric system
What 2 things make up the ejaculatory ducts?
vas deferens (sperm) and seminal vesicle (fluid)
What is the blood supply and innervation of the prostate?
- blood supply: inferior vesicle A. and middle rectal A.
- innervation: prostatic plexus from inferior hypogastric plexus
What are some sx of BPH?
nocturia, dysuria, and urinary urgency
What is BPH and how would you detect it?
hypertrophy of the prostate into the urinary bladder - impedes urination and can lead to cystitis and kidney damage
- detected by a digital rectal exam
Explain the route of the vas deferens
- enters ABD via deep inguinal ring
- passes superior to all structures
- expands into an ampulla before narrowing again to join seminal vesicle duct
Where are seminal vesicles located?
lateral on either side of the ampulla of the vas deferens
What is the vascular supply of the seminal vesicles?
branches of superior and inferior vascular arteries
What is the lymphatic drainage of the vas deferens?
- scrotal portion: external iliac
- majority of vas deferens: internal iliac
What is the lymphatic drainage of the prostate?
internal iliac (most) and some to the sacral nodes
What is the lymphatic drainage of the bladder?
- superior portion: external iliac
- inferior portion (fundus and neck): internal iliac
What is the diagnostic procedure for bladder cancer?
cystoscopy
What 2 pelvic spaces are located in both males and females? What space in a female is a pouch in a male?
- retropubic space
- retrorectal space
- retrovesical space (pouch in males)
Space vs pouch
space - cavity filled w/ fat
pouch - cavity lined w/ peritoneum
What 2 pelvic pouches are unique to females?
vesicouterine pouch and the rectouterine pouch
How can the rectouterine pouch be surgically approached?
through the posterior fornix of the vagina
What is the broad L.?
double fold of peritoneum that goes over the top of the uterus/ovaries and attaches to the lateral wall of the pelvis
What are the contents of the board L. (6)?
- round L. (through inguinal canal and connects to uterus)
- uterine tube
- ovaries
- uterus
- proper ovarian L. (connects ovary to uterus)
- ovarian vessels (within suspensory L.)
Explain each of the following parts of the broad L.: mesometrium, mesovarium, mesosalpinx
- mesometrium: surrounds the uterus
- mesovarium: surrounds the ovaries
- mesosalpinx: surrounds uterine tube
What 2 ligaments combine to support the cervix?
- transverse cervical L. (cardinal L.)
- uterosacral L.
What L. provides the main support for the uterus?
transverse cervical L. (cardinal L.)
What vessels run within each of the following Ls.: lateral bladder L., cardinal L., and uterosacral L.
- lateral bladder L. - superior vesicular A. and V.
- cardinal L. - uterine A. and V.
- uterosacral L. - middle rectal A. and V.
What are the 3 layers of the uterus?
- perimetrium: outside adventitia layer
- myometrium: muscular layer
- endometrium: inner epithelium that changes w/ the menstrual cycle
What are the openings on either side of the cervical portion of the uterus?
internal os and external os
What are the 2 uterine positions? What are they called normally?
- verted: angle between cervix and vagina (normally anteverted)
- flex - angle between uterine body and cervix (normally anteflexed)
What can having a retroverted uterus cause?
- no effect on fertility but can cause lower back pain, dysuria, and dyspareunia (pain during intercourse)
What can having a retroverted and retroflexed uterus cause?
can become trapped in curve of sacrum when pregnant
What is uterine prolapse? What are the varying degrees?
- when pelvic ligaments or pelvic diaphragm weakens/tears and can’t support the uterus (usually by pregnancy)
- 1st degree: small prolapse into vagina
- 2nd degree: uterus enters directly into vagina
- 3rd degree: complete prolapse (vagina falls outside body)
What are the 5 common parts of the uterine tube
- fimbria: finger-like appendages that cover the ovary
- infundibulum: funnel portion that takes up egg from ovary
- ampulla: largest portion of tube
- isthmus: narrow portion near the uterus
- intrauterine portion
What 3 ligaments are attached to the ovaries?
- ovarian L. (round L. of ovary) - attaches ovary to uterus
- suspensory L. - ovary to pelvic wall
- broad L. via the mesovarium
What is the fornix of the vagina?
recess of the vagina that protrudes past the opening to the cervix (due to angle of cervix)
What helps increase the tone of the external urethral sphincter (EUS)?
pelvic floor exercises
At what level is a spinal epidural nerve block injected?
L3-L4
At what level is a caudal epidermal nerve block injected?
L5-S1
How many arteries do males and females have that enter the lesser pelvis? What makes up the difference?
Males: 4 (testicular As. do not enter)
Females: 6 (paired ovarian As. enter)
What are the common As. between males and females that enter the lesser pelvis?
- paired internal iliac A. (x2)
- median sacral A.
- superior rectal A.
What injury can occur when ligating the uterine A.?
can accidentally cut the ureter during a hysterectomy (uterine A. wraps around the ureter)
What injury can occur when ligating the ovarian A.?
can accidentally cut the ureter during oophorectomy (ovarian A. is close to ureter at pelvic brim)
Where do iliolumbar Vs. drain into?
drain directly into common iliac rather than internal iliac
What do superior, middle, and inferior rectal Vs. anastomose as?
rectal portocaval anastomosis (portal system)
What does the lateral sacral V. anastomose with and where does the anastomosis drain?
anastomoses w/ internal vertebral plexus -> IVC/SVC
What are the 2 nerve plexuses of the pelvis?
- sacral (lumbosacral) and coccygeal plexus
What makes up the sacral (lumbosacral) plexus?
anterior rami of S1-S4 and lumbosacral trunk (L4-L5)
Name the 4 branches of the sacral plexus?
- sciatic N. (L4-S3)
- superior gluteal N. (L4-S1)
- inferior gluteal N. (L4-S2)
- pudendal N. (S2-S4)
What does the pudendal N. innervate?
innervates perineum and provides sensory afferents for external genitalia and anal canal (below pectinate line)
What does the sciatic N. innervate?
hamstring muscles, leg and foot
Which nerve from the sacral plexus exits the greater sciatic foramen and enters the perineum via the lesser sciatic foramen?
pudendal N. (PIN structures)
Where would you perform a pudendal N. block/saddle block?
near inferior margin of ischial spine
What do the superior and inferior gluteal Ns. innervate?
- superior gluteal N.: gluteus medius and minimus ms.
- inferior gluteal N.: gluteus maximus
What makes up the coccygeal plexus?
anterior rami S4-S5 and coccygeal Ns. (Co)
What does the coccygeal plexus innervate?
coccygeus M., part of levator ani and sacrococcygeal joint
What branch comes off the coccygeal plexus and what does it innervate?
anococcygeal Ns. -> innervate small area of skin between tip of coccyx and anus
What makes up superior/inferior hypogastric plexuses (sympathetics or parasympathetics)?
- superior: sympathetic
- inferior: sympathetic (superior sacral) and parasympathetic (pelvic splanchnic Ns.)
What plexuses does the superior hypogastric plexus give rise to?
ureteric, testicular, and common iliac plexuses
What 3 things communicate with the inferior hypogastric plexus
- gray rami communicantes (feed sympathetic fibers into anterior rami)
- pelvic splanchnic Ns. (parasympathetics to the plexus)
- sacral splanchnic Ns. (sympathetics to the plexus)
Which artery does the ureter cross anterior to?
common iliac A.
From what lymph nodes do the common iliac nodes receive lymph? Where do they drain?
- receive from sacral lymph nodes, internal iliac lymph nodes, and external iliac lymph nodes
- drain into lumbar lymph nodes
Where do sacral lymph nodes receive lymph from?
rectum, bladder, prostate, cervix, and posterior pelvic wall
Where do internal iliac lymph nodes receive lymph from?
pelvic viscera, deep part of perineum, and gluteal region
Where do external iliac lymph nodes receive lymph from?
deep inguinal lymph nodes anterior ABD wall, bladder, prostate, uterus and upper vagina
What are the 2 branches of the external iliac A.?
- deep circumflex iliac A.
- inferior epigastric A.
What are the 3 branches of the posterior division of internal iliac A.?
- iliolumbar A.
- superior gluteal A.
- lateral sacral A.
What are the 6 branches of the anterior division of the internal iliac A. in females?
What branch comes off in males?
- middle rectal A.
- internal pudendal A.
- vaginal A. (F)
- uterine A. (F)
- obturator A.
- umbilical A.
- inferior vesical A. (M)
What artery supplies the urinary bladder in females? From what artery does it branch?
superior vesical A. -> comes from umbilical A.
Where does the umbilical A. end?
ends in the medial umbilical L.
What do inferior gluteal A. and inferior rectal A. branch off?
internal pudendal A.
What is contained in the perineum?
external genitalia and anal canal
What are the boundaries of the perineum?
- Anterior: pubic symphysis Posterior: coccyx - Anterolateral: ischiopubic ramus - Posteriolateral: sacrotuberous L. - Superior: pelvic diaphragm - Inferior: skin associated w/ external genitalia and anal canal
What is contained within the anal triangle of the perineum?
- anal canal (internal and external sphincters)
What is the perineum divided into?
divided into a urogenital triangle (anteriorly) and an anal triangle (posteriorly)
What are the boundaries of the ischiorectal fossa?
- lateral wall - obturator internus and ischium
- superomedial wall - levator ani and anal canal
- base - skin of perineum
Where is the pudendal canal?
fascia lined space on the medial surface of the obturator internus M.
What passes through the pudendal canal?
- pudendal N.
- internal pudendal A.
- internal pudendal V.
What are the 2 spaces found within the urogenital triangle
- superficial perineal space
- deep perineal space (contains urogenital diaphragm)
What is the name of the lower layer of fascia on the urogenital diaphragm?
perineal membrane
What is the narrowest portion of the male urethra?
membranous urethra (passes through urogenital diaphragm) - contains IUS and EUS
Where does the duct of the bulbourethral gland empty? What does it pass through to do this?
passes through perineal membrane to empty into the spongy (penile) urethra
What is the muscle that runs transversely across the urogenital diaphragm?
deep transverse perineum M.
What are the 4 structures found at the root of the penis?
- crura (2)
- bulb of penis
- ischiocaverous M. (covers the crura)
- bulbospongiosus M. (covers the bulb)
What helps empty the penis of urine/semen?
bulbospongiosus M.
What is found in the shaft of the penis (5)?
- corpus spongiosum (contains penile urethra)
- corpus cavernosum (bilateral)
- Dorsal A/V/N of the penis
What does the vulva consist of (3)?
- labia majora
- labia minora
- clitoris
What is the space between the labia minora called?
vestibule of the vagina
What is contained within the vestibule of the vagina?
- external urethral orifice
- vaginal orifice
- paraurethral glands orifices
- greater vestibular glands orifices
What is another name for the greater vestibular glands and what is their function?
Bartholin’s glands - secrete clear mucus that lubricates external genitalia
What are the 4 parts of the clitoris?
- bilateral crura covered by ischiocavernosus M.
- bilateral corpora cavernosus (continuous w/ crura)
- body
- glans clitoris (visibile externally)
What does the bulbocavernosus M (bulbospongiosus M) cover over in females
bulb of vestibule and greater vestibular glands
What does the external pudendal A. supply?
scrotum/penis (males) and labia majora/clitoris (females)
What type of fibers does the pudendal N. contain?
- preganglionic parasympathetic
- postganglionic sympathetic
- somatic motor and sensory fibers
What 3 branches does the pudendal N. give off?
- inferior rectal N.
- perineal N.
- Dorsal N. of penis/clitoris
What are 6 causes of male impotence?
- nerve damage to prostatic nerve plexus
- atherosclerosis to blood supply of erectile tissues
- NIDDM
- spinal cord injury
- hormonal disorders
- psychological disorders
What is the lymphatic drainage of the superficial perineal space?
superficial inguinal nodes
What is the lymphatic drainage of the deep perineal space?
internal iliac nodes
What is an episiotomy?
surgical incision between vagina and anus to prevent perianal tearing during vaginal delivery
What type of episiotomy is the most common?
medio-lateral episiotomy
What are the 3 layers that require sutures after an episiotomy?
- vaginal wall
- muscle layer
- subcutaneous fascia
What does the round L. of the uterus connect?
connects uterus to labia majora
The inferior gluteal A. can branch of 2 different arteries, what are they?
- internal pudendal A. from anterior division of internal iliac A.
- posterior division of internal iliac A.