Pelvic organs (viscera)

• Ureters


  • Pelvic parts run on the lateral walls of the pelvis parallel to the anterior margin of the greater sciatic notch, between the parietal pelvic peritoneum and the internal iliac arteries
  • Curve anteromedially superior to levator ani and enter the bladder

  
• Ureters in males


  • Anterior to internal iliac artery, medial to obturator, inferior vesical & middle rectal arteries
  • Turn at lower part of sciatic notch to reach lateral end of bladder, anterior to seminal vesicles, crossed by vas deferens above & in front from lateral to medial

  
• Ureters in females


  • Anterior to internal iliac artery, form posterior boundary of ovarian fossa, closely related to uterine artery at medial part of broad ligament, run medially and anteriorly on the lateral aspect of cervix of uterus and upper vagina

  
• Prevention of reflux of urine

  • Ureters pass obliquely through muscular wall of bladder in an inferomedial direction, forming a one-way flap valve, internal pressure of the filling bladder causes the passage to collapse
  • Contractions of the bladder musculature act as a sphincter
• Arterial supply to ureters

  • Ureteric branches from common iliac arteries
  • Internal iliac arteries
  • Ovarian arteries

  
• Most constant arterial supply to terminal parts of ureters

  • Uterine arteries in females
  • Inferior vesical arteries in males

  
• Venous drainage of ureters

  • Parallels the arterial supply

  
• Lymph drainage of ureters


  • To common and internal iliac nodes

  
• Innervation of ureters


  • Derive from autonomic plexuses: renal, aortic, superior and inferior hypogastric

  
• Ureteric pain


  Referred to ipsilateral lower quadrant and inguinal region
• Urinary bladder


  • Tetrahedral in shape when empty
  • Surfaces: superior, right and left inferolateral, posterior
  • Parts: apex, body, fundus, neck

  
• Bladder bed


  • Formed by the structures in direct contact: pubic bones and fascia of levator ani & obturator internus in contact with inferolateral surfaces

  
• Internal bladder walls


  • Composed of the detrusor muscle
  • In males, muscle fibres toward the neck form the involuntary internal urethral sphincter which contracts during ejaculation to prevent semen from entering bladder
  • Trigone of the bladder: ureteric orifices and internal urethral orifice form the angles, uvula of the bladder is a slight elevation, mucosa is smooth only here
• Relations of bladder - in males and females

  • Superior: peritoneum, ileum, sigmoid colon
  • Inferolateral: obturator internus muscle, levator ani muscle, obturator nerve & vessels, superior vesical vessels
  • Anterior: retropubic space, pubic bone (symphysis, crest)

  
• Relations of bladder - in males

  • Posterior: seminal vesicles, vas deferens (& ampulla), rectovesical pouch, ampulla of rectum
  • Inferior: prostate gland, pelvic floor

  
• Relations of bladder - in females

  • Posterosuperior: uterovesical pouch, body of uterus
  • Posterior: cervix, anterior wall of vagina
  • Inferior: pelvic floor

  
• Arterial supply to bladder

  • Superior vesical artery - anterosuperior parts
  • Inferior vesical (males) - fundus and neck
  • Vaginal arteries (females) - fundus and neck
  • Obturator arteries - anterosuperior parts

  
• Venous drainage of bladder

  • Vesical venous plexus drains into internal iliac vein, continuous with prostatic venous plexus in males and uterovaginal plexus in females

  
• Lymph drainage of bladder

  • Internal, external & common iliac nodes to para-aortic nodes
  • Obturator nodes
  • Sacral nodes occasionally

  
• Innervation of bladder


  • Sympathetic: T11-L2 fibres to vesical plexuses via hypogastric plexuses and nerves
  • Parasympathetic: pelvic splanchnic nerves to inferior hypogastric plexus

  
• Male urethra


  • 18-22cm long, divided into 4 parts

  
• Female urethra


  • 4cm long, travels a slightly curved course passing inferiorly through the pelvic floor into the perineum, opens in the vestibule between the labia minora, anterior to the vaginal opening, inferior aspect bound to the anterior surface of the vagina, two small para-urethral mucous glands (Skene's glands) associated with the lower end

  
• Rectum


  • Approximately 12cm long, continuous proximally with the sigmoid colon and distally with the anal canal, rectosigmoid junction lies anterior to the S3 vertebra, taeniae coli and omental appendices are absent
• Rectal flexures


  • Sacral flexure - rectum follows the curve of the sacrum and coccyx
  • Anorectal flexure - sharp posteroinferior angle as the gut perforates levator ani, important mechanism for faecal continence
  • 3 lateral flexures - superior and inferior on the left, intermediate on the right
• Rectal peritoneal reflections


  • Peritoneum covers the anterior and lateral surfaces of the superior 1/3, the anterior surface of the middle 1/3, no surface on the lower 1/3
• Relations of rectum - in both sexes

  • Posteriorly: S3-S5 and coccyx, anococcygeal ligament, median sacral vessels, inferior ends of sympathetic trunks and sacral plexus
  • Anterior: fundus of bladder, terminal parts of ureters, ductus deferentes, seminal glands and prostate, rectovesical septum

  
• Relations of rectum - in females

  • Anterior: vagina, rectouterine pouch, rectovaginal septum
• Arterial supply to rectum

  • Superior rectal artery (unpaired) from IMA - supplies proximal rectum
  • Middle rectal arteries from internal iliac arteries - supply middle and inferior rectum
  • Inferior rectal arteries from internal pudendal arteries - supply the anorectal junction and anal canal

  
• Venous drainage of rectum

  • Superior rectal veins to portal venous system
  • Middle and inferior rectal veins to systemic system

  
• Lymph drainage of rectum

  • Inferior mesenteric nodes, internal iliac nodes, superficial inguinal nodes

  
• Innervation of rectum


  • Sympathetic: lumbar splanchnic nerves, hypogastric/pelvic plexuses, peri-arterial plexus of IMA and superior rectal artery
  • Parasympathetic: S2-S4 via pelvic splanchnic nerves and inferior hypogastric plexuses to rectal plexus

  
• Ductus deferens


  • Continuation of the duct of the epididymis, begins at the tail of the epididymis, ascends posterior to the testis and medial to the epididymis, penetrates the anterior abdominal wall via the inguinal canal as part of the spermatic cord, crosses over the external iliac vessels and enters the pelvis, passes along the lateral wall of the pelvis external to the parietal peritoneum, ends by joining the duct of the seminal vesicle to form the ejaculatory duct

  
• Arterial supply and venous drainage of ductus deferens

  • Artery to ductus deferens from superior (sometimes inferior) vesical artery, terminates by anastomosing with testicular artery
  • Venous drainage via testicular vein

  
• Seminal vesicles


  • Lie between fundus of bladder and rectum, obliquely placed superior to the prostate, secrete a thick alkaline fluid with fructose and a coagulating agent, superior ends covered with peritoneum and lie posterior to ureters, inferior ends closely related to the rectum separated only by the rectovesical septum, duct joins ductus deferens to form ejaculatory duct

  
• Arterial supply to seminal vesicles

  • Inferior vesical and middle rectal arteries

  
• Ejaculatory ducts


  • Arise by the union of the ducts of the seminal vesicles with the ductus deferentes, approximately 2.5cm long, arise near the neck of the bladder, run close together as they pass antero-inferiorly through the posterior part of the prostate, converge and open on the seminal colliculus

  
• Arterial supply and venous drainage of ejaculatory ducts

  • Arterial supply from arteries to the ductus deferens
  • Venous drainage to prostatic and vesical venous plexuses

  
• Prostate


  • 3cm long, 4cm wide and 2cm anteroposteriorly, largest accessory gland of the male reproductive system, surrounds the prostatic urethra, 2/3 is glandular and 1/3 is fibromuscular, has a dense fibrous capsule surrounded by the visceral layer of pelvic fascia

  
• Surfaces and relations of the prostate

  • Base related to the neck of the bladder, apex in contact with fascia on the superior aspect of the urethral sphincter and deep perineal muscles, muscular anterior surface part of the urethral sphincter, posterior surface related to the ampulla of the rectum, inferolateral surfaces related to the levator ani

  
• Lobes of the prostate

  • Anterior lobe, lateral lobes, middle (median) lobe, posterior lobe