Anatomy Gray's Flashcards
prostatic urethra
- part of the male urethra passing thro prostate gland
- begins at i_nternal urethral orifice_ at the antero-inferior angle of vesical trigone
- posterior wall of urethra has an elevated ridge called urethral crest with a prominence called seminal colliculus
The perineum is ______ to the floor of the pelvic cavity; its boundaries form _____.
inferior
the pelvic outlet
corona of the glans
- margin of the glans projecting beyond the ends of the corpora cavernosa
- overhangs the neck of the glans that separates the body from the glans of the penis
labia minora
paired folds of hairless skin
medial to labia majora
extend postero-inferiorly from the clitoris
anterior end of each labium minus divides: anterior division = prepuce of the clitoris, posterior division = frenulum of the clitoris
spermatic cord
- bundle of vessels, nerves and lymphatics ensheathed in layers from abdominal wall
- begins at deep inguinal ring, passes thro inguinal canal and superficial ring to reach testis
- spermatic cord comprises the: ductus deferens, testicular a., pampiniform plexus, deferential a. & v. and genital br. of genitofemoral n.
- coverings of the cord: internal spermatic fascia (from transversalis fascia), cremasteric muscle and fascia (from internal oblique), external spermatic fascia (from external oblique aponeurosis)
2 ligaments of the pelvic wall
sacrospinous and sacrotuberous ligaments
- important bc they link each pelvic bone to the sacrum and coccyx
- also convert 2 notches on the pelvic bones—greater and lesser sciatic notches —into foramina on the lateral pelvic walls.
The external anal sphincter is innervated by ___
- inferior rectal branches of pudendal nerve
- branches directly from anterior ramus of S4
ductus deferens is contenous with ___ , ascends to pass through the abdominal wall via _____
epididymis
the inguinal canal
How does the blood get to the gluteal muscles? (pain in buttocks if obstructed)
aorta bifurcation –> common iliac–> internal exernal iliac–> anterior and posterior branches –> vessels that leave the pelvis through greater sciatic foreaman
1) –> supply gluteal muscles
2) internal pudendal artery from anterior division of internal iliac a. –> penis
features that distinguish the male from the female bony pelvis
subpubic angle:
- male – less than 70º
- female it will exceed 80º
pelvis – (Latin basin) consists of 3 bones: 2 hip bones + sacrum
Unlike the anal triangle, the urogenital triangle contains…..
a strong fibromuscular support platform– perineal membrane and deep perineal pouch (attached to the pubic arch)
vulva
- serves as sensory and erectile tissue for sexual intercourse and arousal
- directs the flow of urine
- prevents entry of foreign material into urogenital tract
- clinically called the pudendum
three bones that form the os coxae:
ilium, ischium, pubis
lesser sciatic foramen
- lies inferior to the pelvic floor
- provides communication bw gluteal region and perineum
clitoris combination of 3 erectile bodies:
glans clitoris
2 corpora cavernosa clitoris
(covered by smooth skin)
labia majora
- fat-filled elevations of hair-covered skin
- lying on either side of the vestibule of the vagina
- labia majora are joined across the midline by the anterior and posterior labial commissures; they blend into each other anteriorly to form the mons pubis
body of the uterus
part of the uterus from the fundus and the isthmus
Sciatic nerve forms at ___ from root of _____.
on anterior belly of piriformis muscle
L4 - S3
uterine artery embolization
- treatment for uterine fibroids (benign tumors)
- use a catheter to inject small particles into the uterine arteries
- This reduces blood supply to the fibroids and causes them to shrink
The pelvic floor is supported anteriorly by:
▪ perineal membrane,
▪ muscles in the deep perineal pouch
Placenta previa
- “leading the way”
- A placenta implanted over the cervical region of the uterus blocking entrance to the birth canal.
- Occurs in less than 1% of pregnancies, but can cause significant bleeding
in men urogenital triangle contains ____
root of the penis
pudendal canal
- a tubular compartment formed in the fascia that covers the obturator internus muscle.
- contains internal pudendal artery + veins.
How to define the margins of the perineum
The pubic symphysis, ischial tuberosities, and tip of the sacrum ( palpable)– thighs flexed and abducted in the lithotomy position
The ischial tuberosities are palpable on each side as large bony masses near the crease of skin (gluteal fold) between the thigh and gluteal region. They mark the lateral corners of the diamond-shaped perineum.
The tip of the coccyx is palpable in the midline posterior to the anal aperture and marks the most posterior limit of the perineum.
The anterior limit of the perineum is the pubic symphysis. In women, this is palpable in the midline deep to the mons pubis. In men, the pubic symphysis is palpable immediately superior to where the body of the penis joins the lower abdominal wall.
epididymis = greek for ___
covering the testicle
penile urethra
- contained within the bulb and corpus spongiosum of penis
- longest part of male urethra
- has a dilation in the region of glans called navicular fossa
- aka: spongy urethra
narrowed inferior end of the uterus
cervix!
– is inferior to isthmus of uterus and projects into vagina; surrounded by vaginal fornices (anterior, posterior and lateral)
The penile part of the male urethra has two angles:
- A fixed angle where urethra bends anteriorly in the root of the penis, after passing through perineal membrane. (more important)
- occurs distally where unattached part of the penis curves inferiorly—when the penis is erect, this second angle disappears.
scrotum in men are analogous to ___ in women
labia majora
Three apertures in the pelvic wall that communicate with the lower limb
- the obturator canal,
- the greater sciatic foramen,
- the lesser sciatic foramen.
inferior rectal nerve
- is often multiple, penetrates through fascia of pudendal canal
- courses medially across ischio-anal fossa to innervate external anal sphincter + related regions of levator ani muscles.
- also general sensory for skin of the anal triangle
- 65-year-old man
- buttock pain and impotence
- reduced peripheral pulse on the left foot compared to the right.
- unable to obtain an erection
- smoked heavily
Left common iliac artery obstruction
(pain in buttocks is ischemic)
sacrotuberous ligament
- Inferior view of pelvis.
- strong, resists tendency of upper body weight to rotate the superior aspect of the sacrum anteriorly.
- It originates from the posterior aspect of the sacrum and extends to the ischial tuberosities.
Varicocele – presentation and treatment
- venous drainage of testis is via pampiniform plexus of veins (runs within the spermatic cord).
- A varicocele = dilated veins that arise from pampiniform plexus.
- soft nodular swelling at the top of testes and epididymis (no pain) — “bag of worms”
- “dragging feeling”
- embolize vessels or surgery through inguinal incision – at inguinal ligament aponeurasis of ecternal oblique is divided
2 muscles of pelvic wall
obturator internus + piriformis muscles – arise in the pelvis and exit through the sciatic foramina to act on the hip joint.
During childbirth, the fetus passes through the _____ from the abdomen, into which the uterus has expanded during pregnancy, and then passes through the _____.
fetus passes through the pelvic inlet from the abdomen, and then pelvic outlet.
Compression of sciatic nerve causes:
pain in gluteal region, posterior thigh, posterior/lateral leg (dermatomes for L4-S3)
muscular weakness, sensory loss, footdrop (common fibial nerve, br of sciatic)
The perineal nerve
- passes into the urogenital triangle and gives rise to motor and cutaneous branches.
- motor branches supply skeletal muscles in the superficial and deep perineal pouches.
- largest of the sensory branches is the posterior scrotal nerve in men and the posterior labial nerve in women.
Structures within the right iliac fossa that may caus pain:
- appendix, cecum, and small intestine
- Musculoskeletal pain and referred pain maybe
- In women, pain may arise from: ovary, fallopian tube, and uterus (rare in young pt)
- Infection and pelvic inflammatory disease may occur in younger pt
uterine artery
- from internal iliac a., anterior division
- branches into: tubal + vaginal
- supplies uterus and uterine tube
- anastomoses with ovarian a. and vaginal a.; it passes superior to ureter in the pelvis (remember: “water under the bridge”)
The _____ contains the external genitalia and external openings of the genitourinary and gastrointestinal systems.
perineum
What is the pelvic diaphragm?
- bowl- or funnel-shaped structure
- 2 levator ani muscles that join each other at midline
- completed posteriorly by the coccygeus muscles
- female pt can’t pass urine after hysteroctomy (a bilateral salpingo-oophorectomy)
- abdomen distended
- fluid in abdomen (urine)
Iatrogenic ureteric injury
the superior region related to upper parts of the ____ and ____ is the false pelvis ( greater pelvis ) and is generally considered part of the ______
pelvic bones + lower lumbar vertebrae
considered part of the abdomen
Bone marrow biopsy: In certain diseases (leukemia), a sample of bone marrow must be obtained to assess stage and severity. Where is it done?
- iliac crest is often used, bc its close to the surface and easily palpated.
- injecting anesthetic in the skin and pass a cutting needle through the cortical bone of the iliac crest.
- bone marrow is aspirated and viewed under a microscope.
- also provide info about bone metabolism
Round ligament of uterus (aka. ligamentum teres uteri)
– traverses the ___ ring to reach lateral surface of uterus
– a remnant of ____
– continuous with ____
– holds the ____ of uterus forward
- superficial AND deep inguinal ring AND inguinal canal
- gubernaculum
- ovarian ligament
- fundus
ampulla of the ductus deferens
- joins with the duct of the seminal vesical to form the ejaculatory duct
- dilated part of the ductus deferens located posterior to the bladder
ischium
the “V”- shaped bone that forms the posteroinferior part of the pelvis
ejaculatory duct
- formed by joining of duct of seminal vesicle and ampulla of the ductus deferens
- ejaculatory duct passes through the prostate gland to empty onto the seminal colliculus along the urethral crest in the prostatic urethra
3 parts of the epididymis
beginning of the duct system of the testis
- head– on superior surface of testis, receives sperm from efferent ductules
- body – postero-lateral to testis, separated from it by sinus of epididymis
- tail – inferiorly, continuous with ductus deferens
possible location of a pelvic kidney, symptoms?
(other one may be normal)
L5 or L4
behind the bladder
No symptoms
In women, these organs can develop large masses:
- ovaries (solid and cystic tumors)
- embryological remnants within the broad ligaments and the uterus (pregnancy, fibroids)
slit like opening of the spongy urethra near the tip of the glans
external urethral meatus (orifice)
ampulla
= a flask or the dilated part of a duct or channel
Abscesses in the ischio-anal fossae
anal mucosa is particularly vulnerable to injury and may be easily torn by hard feces.
pt may develop inflammation and infection of anal canal (sinuses or crypts), can spread between sphincters, producing intersphincteric fistulas.
infection can move superiorly into pelvic cavity or laterally into ischio-anal fossae.
The only structure that passes between the ureter and the peritoneum in men is ____ .
In women, as the ureter descends on the pelvic wall, it passes ____ .
the ductus deferens
under the uterine artery
The urogenital triangle is defined:
- laterally by the ischiopubic rami,
- posteriorly by an imaginary line between the ischial tuberosities, and
- anteriorly by the inferior margin of the pubic symphysis.
* As with the anal triangle, roof/ceiling of the UG triangle is levator ani.
membranous urethra
part of the urethra that passes through urogenital diaphragm (sphincter urethrae muscle and perineal membrane)
female: connects urinary bladder to external urethral orifice at vestibule of vagina
male: connects prostatic urethra with spongy/penile urethra
Somatic nerves: Pudendal nerve
The major somatic nerve of the perineum
originates from the sacral plexus and carries fibers from spinal cord levels S2 to S4.
It leaves pelvic cavity through the greater sciatic foramen inferior to the piriformis muscle, passes around the sacrospinous ligament, and then enters the anal triangle of the perineum by passing medially through the lesser sciatic foramen.
As it enters and courses through the perineum, it travels along the lateral wall of the ischio-anal fossa in the pudendal canal
skeletal muscles of perineum and pelvic floor (external anal sphincter, external urethral sphincter) are innervated by spinal cord levels …..
S2 to S4
In women, ureter continues close to ____ of the vagina, especially on the left, and enters the ___ of the bladder.
lateral fornix of the vagina
postero-superior angle of the bladder
The anal canal passes from the pelvis to the perineum through
a posterior circular orifice in the pelvic diaphragm.
sacrotuberous ligament attached to
ischeal tuborisity
what’s anterior to the rectum?
prostate in men
uterus in women
The superficial perineal pouch contains:
- erectile structures that join together to form the penis/ clitoris
- skeletal muscles associated with erectile structures attached to the perineal membrane and adjacent bone.
dorsal nerve of the penis and clitoris
- enters deep perineal pouch
- passes along lateral margin of the pouch, then exits by passing inferiorly through the perineal membrane (just inferior to pubic symphysis) where it meets body of clitoris or penis.
- It courses along dorsal surface of body to reach the glans.
- dorsal nerve is sensory to the penis and clitoris, particularly to the glans.
The pudendal nerve has three major terminal branches
inferior rectal
perineal nerves
dorsal nerve of the penis/clitoris
** each accompanied by branches of internal pudendal artery
usign a bimanual examination can palpate these in women:
- cervix
- lower part of the body of the uterus
- ovaries and uterine tubes.
a band of connective tissue that connects the ovary to the lateral surface of the uterus
ovarian ligament
- a remnant of the gubernaculum
- it is continuous with the round ligament of uterus (on the sides)
- lies within the mesovarium/ proper ovarian ligament
ectopic pregnancy case
- positive pregnancy test.
- ruptured fallopian tube caused by an ectopic pregnancy
- no fetus or sac in uterus
- 25 yr old
- pain in right iliac fossa, rapidly developed (40 min)
- associated with cramps and vomiting
ductus deferens is continuous with _____, passes through _____ to reach behind/under the bladder to join duct of the seminal vesicle to form _____
- continuous with the tail of the epididymis
- it passes through the superficial inguinal ring, inguinal canal and deep inguinal ring
- the ejaculatory duct
rounded, fatty prominence anterior to the pubic symphysis
mons pubis
obturator canal forms a passageway between ___, is formed by ____
- the pelvic cavity and the adductor region of the thigh
- formed in the superior aspect of the obturator foramen (between bone, a connective tissue membrane and muscles that fill the foramen)
coccygeal vertebrae
- are reduced in complexity
- have no pedicles, laminae or spines
- all 4 may be fused together or only 3 fused togeher
when muscular branches of the ___ artery are occluded/stenosed, pt develop ischemic pain in the calf muscles called intermittent claudication.
femoral artery
Much of the somatic motor and sensory innervation of the perineum is provided by
the pudendal nerve from S2 to S4.
testicular artery
- from aorta
- suppiles testis and epididymis
