Blue Boxes IV - pt. 2 Flashcards
Accessory renal vessels
During kidney ascent, blood supplied by successively superior arteries w/ degeneration of the inferior arteries (failure to degenerate forms an accessory a./v.)
Polar a. –> accessory renal a. entering a pole of the kidney
Inferior polar a. –> crosses ureter and may obstruct it
polar vs. inferior a.
types of accessory renal a.
Polar a. –> accessory renal a. entering a pole of the kidney
Inferior polar a. –> crosses ureter and may obstruct it
Bifid Renal Pelvis/Ureter
Due to incomplete division of metanephric diverticulum (ureteric bud)
supernumerary kidney
Due to complete division of metanephric diverticulum (ureteric bud)
Retrocaval ureter
Ureter leaves passes posterior to IVC; rare
horseshoe kidney
Rare inferior pole fusion of kidneys over the aorta/IVC
lying at L3-L5 level
halted beneath the inferior mesenteric artery
Ectopic pelvic kidney
Failure of the embryonic metanephros to enter the abd
leaves the kidney anterior to the sacrum with blood supplied by aortic bifurcation/common iliac artery
Renal/Ureteric Calculi
pass into renal pelvis and into the ureter, causing distension of the
ureter with severe intermittent pain (ureteric colic; may be referred to lumbar/inguinal/external
genital regions) as it is forced down
Nerve fibers responsible for referred pain of kidney stones
usually referred by visceral afferents to T11-T12 level extending to proximal anterior
thigh and scrotum/labia majora (L1, L2) via the genitofemoral nerve as the stone passes downward
(sympathetic least splanchnic n.
via aorticorenal ganglia transmits generalized nausea and cramping)
Where might kidney stones be entrapped? (3 places)
- At the point of the renal calyx/renal pelvis.
- As it passes in the ureter over the pelvic brim (over the iliac arteries).
- As it passes into the bladder (ureteric orifice).
Referred pain from diaphragm
- Irritation of diaphragmatic pleura or peritoneum referred to C3-C5 dermatomes (shoulder region), w/ ventral rami contributions of these regions to the phrenic nerves
- Irritation of the peripheral diaphragm (innervated by inferior intercostal n.) is localized to skin over costal margin
psoas abcess
Spread of lumbar spinal TB into the psoas sheath, producing an abscess that spreads inferiorly over the pelvic brim, deep to the inguinal ligament and out in the superior thigh
Pus may enter underneath the inferior part of the iliac fascia (into the iliacosubfascial fossa), allowing the cecum/appendix or sigmoid colon to trap in the fossa –> pain
Abdominal Aortic Aneurysm
Arises from a congenital or acquired weakness of the arterial wall, and can be detected by deep palpation of the midabdomen, w/ aneurysms detected further left of the midline.
Ruptured aneurysm –> severe back/abdominal pain and hemorrhage.
What sorts of tumors may appear as aortic aneurysms?
Pancreatic/stomach tumor may transmit aortic pulsations, causing them to appear as aneurysms
Gynecoid (pelvic variation)
Normal female type; rounded pelvic inlet with wide transverse diameter
(platypelloid is the other common female type)
Android (pelvic variation)
Normal male type, which if present in a female, can pose issues with vaginal delivery of a fetus (craniopelvic mismatch)
Anteroposterior compression of pelvis causes fracture of …
pubic rami
Lateral compression of pelvis causes fracture of …
acetabula and ilia
Fractures of the bony pelvic ring are almost always multiple fractures or a fracture combined with _________.
a joint dislocation
exp. hard to break a pretzel ring at just one point
Weak points of pelvis
pubic rami, acetabula, sacroiliac joints and alae of ilium
Iatrogenic Injury of ureter during hysterectomy
Ureter passes inferior to uterine a. near the lateral part of the fornix of the vagina
This makes it susceptible to damage during hysterectomy (when uterine a. is ligated and severed)
Iatrogenic Injury of ureter during ovariectomy
ureter can be damaged when the ovarian vessels are ligated/severed as they cross over the pelvic brim together
Rectal Examination
Structures to palpate?
What might impede scope passage?
- Palpate prostate (L/R lobes), seminal vesicles or cervix.
- Palpate sacrum/coccyx, ischial tuberosities/spines and enlarged iliac lymph nodes, thickening of the ureters, or swellings of the ischioanal fossae (abscesses or abnormal contents of the rectovesical or rectouterine pouches)
- Transverse rectal folds may impede scope passage
Prostate Hypertrophy
may distort the prostatic urethra impeding urine flow
usually due to middle lobe enlargement which causes further occlusion with strain
sx: nocturia, dysuria, urgency
inc risk of bladder infection (cystitis) and kidney damage
prostate cancer metastasis
can metastasize to internal iliac/sacral lymph nodes or to Batson’s Plexus (internal vertebral plexus) to the brain
Vaginal examination
can palpate cervix, ischial spines, sacral promontory and pulsations of the uterine arteries in the lateral parts of the fornix, along with ovarian cysts
Uterine Examination
Bimanual palpation: Two fingers anteriorly in vagina while other hand presses inferoposteriorly in the pubic region of the anterior abdomen
^can detect whether the uterus is in its normal anteverted position
Hegar’s Sign
Softening of the uterine isthmus, causing cervix to feel separated from the body – early pregnancy sign
Normal proportion of uterus at birth
body:cervical ratio 2:1
Normal proportion of uterus postpartum
shrinks to childhood dimensions (1:1 body:cervical ratio)
Normal proportion of uterus during puberty
Uterine body grows, returning to 2:1 size
Normal proportion of uterus Postpuberty/Premenopausal
Pear-shaped body, with thick walled ⅔ lying within the pelvic cavity
Normal proportion of uterus during pregnancy
Massive expansion and thinning of the walls
after delivery –> thick-walled and edematous, w/ a nodular body extending into the pelvis and causing a protrusion of the inferior abdominal wall
Normal proportion of uterus during menopause
Decreased size, involuted and assuming childhood proportions (1:1)
Spinal Anesthesia
Anesthetic into subarachnoid space at L3-L4 producing complete anesthesia below waist level
Perineum, pelvic floor, birth canal are anesthetized with loss of motor/sensory function in lower limbs
Pudendal Nerve Block
Anesthetic peripherally blocking S2-S4 dermatomes (including most of the perineum and inferior quarter of the vagina).
Pain still felt in the superior birth canal (uterine cervix and superior vagina) and sensation of uterine contractions is maintained.
Readministration can be dangerous for pregnancy.
Caudal Epidural Block
aka saddle block
Administered in advance of delivery via injection through the sacral hiatus.
Blocks S2-S4 nerve roots, including afferent pudendal nerve fibers and pain fibers of the cervix/superior vagina.
(anesthetizes sub peritoneal + somatic areas inner. by pudendal n.)
Perineal Body Disrupt`
Perineal body=supports muscles that cross the pelvic outlet (insertion point)
May be disrupted during childbirth, causing prolapse of the pelvic viscera (bladder, through urethra), prolapse of uterus/vagina (through vaginal orifice)
Can be caused by trauma,
May result in diastasis (separation) of the puborectalis and pubococcygeus parts of the levator ani
- -> cystoceles, rectoceles, enteroceles
- -> bladder, rectum, or rectovaginal pouch herniations into the vaginal wall
Episiotomy
Incision of perineum and inferoposterior vaginal wall enlarges the vaginal orifice during childbirth.
Median Episiotomy
Incision through the perineal body, causes scar produced to be similar to the fibrous CT of the perineal body itself
further tearing is toward the anus with risk of anovaginal fistulae or sphincter damage
Mediolateral Episiotomy
Lower incidence of damage to anal sphincter
Rupture of Male Urethra
via rupture of intermediate part of the urethra
Rupture of intermediate part of the urethra (inferior to prostate) can occur with pelvic girdle fractures (when pubic symphysis and puboprostatic ligaments are separated) causing extravasation of urine/blood into the deep perineal pouch
Rupture of Male Urethra
via rupture of corpus spongiosum
Rupture of corpus spongiosum (spongy/penile urethra) at the bulb of the penis often occurring with a straddle injury/false passage of Foley catheter
Causes extravasation of urine into the superficial perineal space, building up in the scrotum, around the penis, or within fascial layers surrounding the tissues
Internal hemorrhoids
Prolapsed rectal muscosa containing internal rectal venous plexus veins, w/ breakdown of muscularis mucosa layer
May be compressed by sphincters if near the anal canal
External hemorrhoids
Thromboses in the external rectal venous plexuses covered by skin
How do anastomoses between superior/middle/inferior rectal veins provide a portovenous shunt
Superior Rectal Vein drains to inferior mesenteric vein.
Middle, Inferior Rectal Veins drain through systemic venous system via internal iliac vein to IVC.
How can portal HTN lead to varicosities in the rectal region?
Portal HTN can cause blood to backup through the portal system through the superior rectal vein and out to the systemic venous system via the middle/inferior rectal veins –> varicosities.
How is pain superior to pectinate line transmitted?
via visceral fibers, making it virtually insensitive
How is pain inferior to pectinate line transmitted?
via somatic fibers of the inferior anal/rectal nerves, making it highly sensitive
Urethral Catheterization
Intermediate part of the urethra just past the corpus spongiosum flexes anteriorly and is vulnerable to puncture along the bulb of the penis, at the point where it passes through the external urethral sphincter
Pudendal Block
Injection made where pudendal n. crosses the lateral aspect of the sacrospinous ligament near attachment to the ischial spine
Ilioinguinal Block
Abolishes sensation in anterior perineum
Urethral stricture
may result from external trauma of the penis or infection of the urethra.
Urethral sounds are used to dilate the constricted urethra in such cases (spongy urethra will expand enough to permit passage of an instrument ~8 mm in diameter)
narrowest and least distensible part of the male urethra
external urethral orifice
