Pelvic Viscera I Flashcards
What is the urinary bladder?
Muscular, pyramidal shaped sac for urine storage
Apex attached to median umbilical ligament
Located in anterior pelvis, filling extends bladder superiorly into abdominal cavity
What is a suprapubic cystostomy?
Suprapubic catheterization to draw urine from bladder
Doesn’t enter peritoneal cavity
What are the muscles of the bladder?
Detrusor muscles - three layered smooth musccular coat, stimulated by parasympathetic fibers of pelvic splanchnic nerves, inhibits by sympathetic fibers from T12-L2
Internal urethral sphicter of Bladder - males only, stimulated by sympathetics, inhibited by parasympathetics
What is the trigone?
Smooth triangular area on inner surface of posterior wall of bladder
Upper corners mark openings of ureters
Lower corner marks inernal origice of urethra
What is micturition?
Excretion of urine
Result of PNS stimulation causing detrusor contraction
What is the innervation to the bladder?
Pelvic splanchnic nerves - detrusor and IUS
Afferents are supplied by S2-S4 via pelvic splanchnic nerves and T11-L2 (inferior thoracic and upper lumbar)
What is a neurogenic bladder?
Dilated, flaccid bladder due to spinal cord injury at S2-S4 (loss of PNS)
Where is referred pain from the bladder?
Tip of penis (S2-S4) or hypogastric region of anterior abdominal wall (L1)
What is the blood supply to the bladder?
Superior and inferior vesical arteries
Vesical venous plexus - surrounds neck of bladder, drain into inernal superior/inferior vesical veins
Where do the lymphatics from the bladder drain?
Internal Iliac nodes
What are key characteristics of the female urethra?
Anterior to vagina
External urethral sphincter under voluntary control by perineal branch of pudendal nerve
Bladder infections (cystitis) are common since it is only 1.5” long
Injury to vagina can involve urethra
What is the rectum?
Continuation of sigmoid colon arising at S3
No taenia coli, haustra, or appendices epiploicae
What structures lie posterior to the rectum?
Sacrum/Coccyx
Piriformis
Sympathetic trunk
What structures lie anterior to the rectum in males?
Posterior Bladder
Ductus deferens
Seminal Vesicles
Prostate
Rectovesical spetum lies between base of bladder and rectum
What structures lie anterior to the rectum in females?
Vagina and Cervix
Rectovaginal septum separates vagina from rectum, can limit spread of infection
What structures lie lateral to the rectum?
Ischial spine
Ischial tuberosity
Sacrotuberous ligament
What is the rectovesical pouch (male)?
Formed by the reflection of peritoneum from rectum to superior-posterior bladder
Lowest part of male peritoneal cavity
Peritoneal exudates (peritonitis) will drain into this pouch in sitting or supine positions
What is the rectouterin pouch (females)?
Formed by reflection of peritoneum from rectum to posterior vagina and uterus
Peritoneal exudates, acid from duodenal ulcer, or blood from rptured ectopic pregnancy willd rain here in siting or supine positions
What are the transverse rectal folds?
3 semicircular horizontal folds of rectal mucosa
Hard stool or proctoscope can tear folds; leads to infection of rectal wall
What is the blood supply to the rectum?
Superior rectal artery
Middle rectal arteries (2)
Inferior rectal arteries (2)
Anastomose with each other
Where do lymphatics from the rectum drain?
Inferior mesenteric nodes
What is the innervation to the rectum?
PNS from pelvic splanchnic nerves fia inferior hypogastric plexus
SNS from superior and inferior hypogastric plexuses
What is rectal prolaspe?
Abnormal descent of rectum through anal canal
Can occur in young children
What is the anal canal?
Terminal part of large intestine
Two sphincters that surround canal
What is the internal anal sphincter?
involuntary control
Thickening of smooth circular muscle of upper part of anal canal wall
PNS stimulation relaxes sphincter
What is the external anal sphincter?
Voluntary control
Striated muscle surrounding lower part of canal
Deep/Superficial/and subcutaneous parts
Innervated by inferior rectal nerve - closes canal
What is the anorectal junction?
Demarcation between the rectum above and the anal canal below
Location of puborectalis muscle sling
What is the puborectalis?
Surrounds anorectal junction
Aids closure of anorectal junction by drawing posterior wall of anal canal anteriorly
What are anal columns?
Characteristic vertical folds of mucous membrane in upper anal canal
Location of portal-caval anastomoses
What are the anal valves?
Semilunar epithelial folds joining inferior ends of anal columns
Indicate the pectinate line
What are the anal sinuses?
Recesses superior to anal valve between anal columns
What is the innervation to the upper half of anal canal?
Stretch receptors and other visceral afferents to hypogastric plexus of autonomic system
No somatic sensory
What is the blood supply to the upper interior half of anal canal?
Superior rectal artery and vein
Where do the lymphatics from the upper half of the anal canal drain?
Inferior mesenteric nodes
What is the innervation to the lower half of the anal canal?
Somatic sensory from inferior rectal nerve
Pain/touch/temperature
Very sensitive
What is the blood supply to the lower half of the anal canal?
Inferior rectal artery and veins
Where do the lymphatics from the lower half of the anal canal drain?
medial nodes of the Superficial inguinal nodes
What are internal hemorrhoids?
Varicosities of tributaries of superior rectal veins in anal columns
Not as painful as external hemorrhoids
What are external hemorrhoids?
Varicosities of tributaries of inferior rectal veins
Very painful
What are the clinical complications of the anal valves?
Can be torn by hard stools in constipation
Results in infection and fistula in wall into ischiorectal fossa
Results in perianal abscess
How does the ductus deferens enter the pelvis?
Crosses over external iliac artery and ureter
Ejaculatory duct is formed by the terminal part of the ductus deferens joining the duct of the seminal vesicl
What is the seminal vesicle?
Lobular sac on posterior surface of bladder
Secretes thick fluid that contains nutritive substances for sperm
What is the prostate gland?
Accessory reproductive gland that produces alkaline secretion which is added to semen to neutralize acidity of vagina
What is the clinical significance of the median lobe of the prostate?
Common site for benign prostatic hyperplasia
Bulges into bladder at internal urethral orifice, causes nocturia
What is the clinical significance of the right and left lateral lobes of the prostate gland?
May become enlarged in BPH and compress urethra
What is the clinical significance of the posterior lobe of the prostate?
Common site for carcinoma
What is the vascular supply to the prostate?
Branche sof inferior vesical artery
Prostatic venous plexus - valveless
*Prostatic carcinoma can spread extensively via venous communications
Where do the lymphatics from the prostate drain?
Internal Iliac nodes
What is the prostatic urethra?
Widest and most dilatable part of urethra
Contains urethral crest, prostatic sinus, seminal colliculus
What is Iatrogenically induced sterility?
Disruption of SNS to ductus deferens, prostate and seminal vesicles results in sterility due to no emission
Occurs as a result of pelvic surgery
