Module 3: The pelvis and perineum Flashcards
What does the bony pelvis consist of?
Right and left hip bones, sacrum, coccyx
What is hip bone composed of?
Ilium, ischium, pubis
What is the pelvic cavity divided into?
- Greater (false) cavity
- Lesser (true) cavity
*separated by pelvic brim
Greater cavity
Region above pelvic brim
Lesser cavity
Below pelvic brim
Contains a pelvic inlet and pelvic outlet
Pelvic floor
Wide thin muscular layer of tissue that forms the inferior border of abdominopelvic cavity
Female pelvis
Wider and more shallow, with a lager inlet and outlet
Subpubic angle of female pelvis
90-100 degrees
Subpubic angle of male pelvis
70 degrees
Joints of the pelvis
- Sacroiliac joint
- Pubic symphysis
Symphysis pubis dysfunction
Instability of the pubic symphysis at the pelvic joint during pregnancy
Results in increase in symphyseal width and mobility
Symptoms of symphysis pubis dysfunction
Difficulty walking, pain localized to pubic area , pain that worsens w weight bearing activities and pain in perineum region
Features of pelvic floor
Levator ani
Coccygeus
Urogenital hiatus
Anal aperture
The puborectal sling
Attaches to pubic bone and wraps posteriorly around rectum forming the anorectal flexure
What forms the puborectal sling?
Fibres of the levator ani muscle group
Pelvic organ prolapse
Protrusion of pelvic organs through vaginal wall resulting from weakened pelvic floor that causes a drop of pelvic viscera
Who is pelvic organ prolapse more common in?
Females, after birth
What are the structures that may prolapse in females?
Bladder, rectum, uterus, cervix, vagina
What are the structures that may prolapse in males?
Rectum
Symptoms of pelvic organ prolapse
Difficulty initiating urine flow, strain to defecate
Two distinct pouches of the female pelvic peritoneum
- Vesicouterine pouch
- Rectouterine pouch
Vesicouterine pouch
Anterior abdominal wall to upper surface of urinary bladder
Anterior surface of uterus
Rectouterine pouch of Douglas
Anterior surface of rectum, btwn uterus and rectum
Pouch of the male pelvic peritoneum
Rectovesical pouch
Rectovesical pouch
Superior surface of urinary bladder to anterior surface of rectum
Pathway of ureter
- Abdominal wall: crosses over common iliac arteries
- Pelvic cavity: enters urinary bladder posteriorly
- Pelvic wall
- Males: ductus deferens cross ureter where ureters drain into bladder
- Females: each ureter crossed by uterine artery
Urinary tract infection
Bacterial infection in any part of urinary system
Why are females at a higher risk of UTI?
Shorter urethra- bacteria doesn’t have to travel far to infect bladder
Most common sites of UTI
Urethra and bladder
Symptoms of UTI
Burning with urination, localized pain at bladder, centre of pelvis and around pubic bone
Sigmoid colon
Forms S-shaped loop in upper pelvic cavity, ends at S3, continuous w rectum
Rectum
Follows curvature of sacrum (sacral flexure) before turning posteriorly at anorectal flexure, ends at anal canal
Location of rectum in females
Posterior to uterus
Location of rectum in males
Posterior to bladder
Venous drainage of sigmoid colon and rectum
Inferior mesenteric vein
Pregnancy hemorrhoids
Occurs in third trimester when veins in lower rectum become large and swollen
Symptoms of pregnancy hemorrhoids
Painful and itchy swellings in lower rectum, near anus, constipation, blood in stool if blood vessels rupture
Vas deferens
Superior to epididymis
Meets with seminal vesicle to form ejaculatory duct
Location of prostate
Inferior to bladder
Anterior to seminal vesicle
Pathway of vas deferens
Through inguinal canal with spermatic cord
Epididymitis
Bacterial infection of epididymis
Affects testis, epididymis, vas deferens, bladder
Epididymitis in children who havent hit puberty
Infection may start in bladder or kidney before spreading through ejaculatory duct to vas deferens to reach epididymis
Symptoms of epididymitis
Localized pain of infected testicle, fever, unilateral swelling of testes
Prostate tumor
Present in males 50+, as it grows it presses on prostatic urethra and disrupts flow of urine
Symptoms of prostate tumor
Difficulty urinating, blood in urine/semen
Male reproductive vasculature
Testicular artery
Artery to vas deferens
Pampniform plexus
Cremaster artery
Where does the testicular artery branch off?
Abdominal aorta
Where does the artery to the vas deferens branch off?
Internal iliac artery
What is the pampniform plexus?
Network of veins that drains venous blood from testis into testicular vein
What does the cremaster artery supply?
Fascial coverings and muscle of spermatic cord
Testicular torsion
Testis rotate, twisting the spermatic cord that supplies and drains blood from testis
**age 12-18
Symptoms of testicular torsion
Sudden, severe pain, swelling, change in scrotum colour (redness/darkening) on affected side of scrotum, localized pain in inguinal region of abdomen
Location of vagina
Inferior to uterus
Anterior to rectum
Posterior to bladder
Ectopic pregnancy
Egg attaches somewhere outside of uterus such as in uterine tube
Symptoms of ectopic pregnancy
Usual pregnancy symptoms at first
Then as embryo grows theres pelvic pain on affected side, and sharp pain if fallopian tubes burst
Arterial supply of female reproductive system
Ovarian arteries
Uterine arteries
Vaginal branches of uterine and internal iliac arteries
Ovarian arteries
Lateral branches of abdominal aorta at L1, supply ovaries and distal uterine tubes
Uterine arteries
Branches of internal iliac arteries, anastomose w ovarian arteries, supply proximal uterine tubes
Venous drainage of female reproductive system
Right and left ovarian vein
Right and left uterine veins
Right and left ovarian vein
Right drains into IVC while left drains into left renal vein
Uterine veins
From a plexus that drains to internal iliac veins
Ovarian cysts
Fluid filled sac that develops on an ovary, may effect ovaries, mesosalphinx (pelvic peritoneum) and ovarian arteries
Symptoms of ovarian cysts
Unilateral pelvic pain (dull and heavy) localized to ovary w cyst, pain during intercourse
Perineum
Diamond shaped area bounded by pubis symphysis anteriorly, ischial tuberosities laterally and coccyx posteriorly
What is the perineum divided into?
Anal triangle posteriorly and urogenital triangle anteriorly
Perineal membrane
Separates the urogenital triangle into superficial and deep pouches
Pouches of the urogenital triangle
Superficial perineal pouch
Deep perineal pouch
Superficial perineal pouch
Contains muscle, skin, external genitalia
Deep perineal pouch
Contains urogenital diaphragm, external urethral sphincter and deep transverse perineal muscles
Perineal body
Fibromuscular mass at centre of perineum that provides attachment for muscles of perineum and strengthens pelvic floor
Ischiorectal fossa
Wedge-shaped space btwn ischium and anal canal, allows for expansion of anal canal during defecation
Pudendal canal
On lateral wall of each ischiorectal fossa, formed within obturator fascia, contains pudendal nerve and internal pudendal vessels
Ischiorectal abscesses
Infection of the anal canal that causes abscesses that perforate laterally through the external sphincter into the lower ischiorectal space
Symptoms of ischiorectal abscesses
Pain/discomfort when walking and sitting, painful defecation, painful, swollen and tender at site of abscesses
Muscles of the penis
- Ischiocavernosus
- Bulbospongiosus
Ischiocavernosus
Cover 2 cura of the penis at the root
Bulbospongiosus
Cover bulb of penis
Foreskin of penis
Thin, loose skin at back of glans
Frenulum of penis
Fold of skin attaching to foreskin on ventral surface of glans
Advantages of having cicumsised penis
Reduces risk of bacterial growth that can cause infection or inflammation of foreskin
Disadvantages of having circumsised penis
Surgical complications such as bleeding, infection; decreased sensitivity at glans due to a loss of nerve endings
Balantis
Inflammation of foreskin or head of penis due to infection or chronic skin conditions in uncircumsised men
Symptoms of balantis
Pain, red, swollen penis, sometimes painful urination
How is the clitoris attached to the perineal membrane
2 cura and 2 vestibular bulbs
Parts of the clitoris
- Body
- Glans
Body of clitoris
Formed by union of right and left crus
Glans of clitoris
Distal, formed by union of vestibular bulbs
Female external genitalia
Mons pubis
Prepuce
Frenulum
Mons pubis
Rounded mass of fatty tissue formed by union of labia majora
Prepuce
Anterior and superior to clitoris, formed by union of labia minora
Frenulum
Anterior and inferior to clitoris, fusion of labia minora forms one frenulum
Vulvitus
Inflammation of vulva (labia majora and minora)
Symptoms of vulvitis
Redness and swelling in vulva, itching and burning, some cases vulva turns white, cracks or develops fluid filled blisters that break open, ooze and crust over
The greater vestibular glands
Posterior to vestibular bulbs on each side of vaginal orfice
Produce mucus during sexual arousal, carried by ducts that open at vaginal orfice
What are the greater vestibular glands homologous to in males?
Bulbourethral glands
Muscles of the clitoris
Two ischiocavernosus muscles cover the cura
Two bulbospongiosus muscles cover the vestibular bulbs and greater vestibular glands
Vasculature of the pelvis and perineum
Umbilical artery
Inferior vesicle artery
Internal pudendal artery
Umbilical artery
Transport deoxygenated blood from fetus to placenta, after birth proximal branches become superior vesical artery that supplies upper part of bladder
Inferior vesicle artery
Supplies bladder, ureter, seminal vesicles, prostate and ductus deferens
How does the internal pudendal artery enter the perineum?
Exits through greater sciatic foramen and enters lesser sciatic foramen to perineum through pudendal canal
What does the internal pudendal artery supply?
Skin and muscles of anal triangle, urogenital triangle and associated erectile bodies
Priapism
Common side effect of drug use, leads to prolonged (>6hrs) painful erection of penis or clitoris unassociated with sexual arousal
Female priapsim
Impaired outflow of blood, swollen clit due to inadequate drainage
Male priapism
Uncontrolled inflow of blood from branches of internal pudendal artery leading to red and swollen glans and shaft of penis
Pudendal nerve
S2-S4
Main branch of sacral plexus to perineum
Where does the pudendal nerve travel?
Leaves through greater sciatic foramen, crossing the ischial spine and enters perineum through lesser sciatic foramen
Where does the perineal nerve travel?
Branch of pudendal nerve that runs from deep perineal pouch to the superficial pouch
What does the perineal nerve supply?
Sensory and motor innervation to urogenital region
