Pelvis

• Organs in the pelvic region within the peritoneal cavity

  • Uterus
  • Ovaries
  • Fallopian tubes (in females)
  • Parts of the urinary bladder
  • Parts of the rectum
• Peritoneal structures in the pelvic region

  • Broad ligament
  • Mesometrium
  • Mesosalpinx
  • Mesovarium (in females)
• Recesses in the pelvic peritoneal cavity

  • Rectouterine pouch (in females)
  • Rectovesical pouch (in males)
  • Vesicouterine pouch (in females)
• Structures and recesses in the pelvic region

  • Contribute to the support, protection, and mobility of the pelvic organs within the peritoneal cavity
• Pelvic cavity


  Formed by three bilateral pairs of bones (pubis, ilium and ischium) and two posteriorly located bones (sacrum and coccyx)
• Parts of the pelvic cavity

  • False pelvis (spans the region below the iliac crest and above the arcuate line)
  • True pelvis (begins below the arcuate line)
• Peritoneal cavity


  Caudal end rests in the pelvic cavity, so spaces associated with this region are also considered part of the pelvic cavity spaces
• There are differences between the male and female internal and external reproductive organs, so there are also some differences in the spaces of the pelvic cavity in that regard
• Pelvis


  Inferior most part of the trunk, consisting of the pelvic girdle and perineum, supporting the urinary and reproductive organs
• Pelvic floor


  Formed by the funnel-shaped pelvic diaphragm, comprising the levator ani muscle and the coccygeus muscle, supporting the pelvic organs and preventing prolapse
• Perineum


  Part of the pelvis containing the external genitalia and anus, inferior to the pelvic diaphragm
• Female pelvis


  • Broader and larger than the male pelvis to provide a comfortable environment for fetus development
• Contents of the lesser pelvis in females

  • Distal parts of the urinary and digestive systems: ureter, urinary bladder, urethra and rectum
  • Internal genitalia: ovaries, uterine tubes, uterus and vagina
  • External genitalia, contained by the perineum
• Rectouterine pouch of Douglas

  Space between the middle and superior rectum and the uterus
• Vesicouterine pouch


  Space between the posterior surface of the urinary bladder and the anterior surface of the uterus
• Male pelvis


  • Narrower than the female pelvis
• Contents of the lesser pelvis in males

  • Distal parts of the urinary and digestive systems: ureter, urinary bladder, urethra and rectum
  • Internal genitalia: testes, epididymides, ductus deferens, seminal glands, ejaculatory ducts, prostate, and bulbourethral glands
  • External genitalia within the perineum
• Male urethra


  Extends from the inferior wall of the bladder, penetrates the prostate and then enters the perineum, passing through the penis and opening at the external urethral orifice
• Pararectal fossa


  Spaces surrounding the intraperitoneal portion of the rectum, limited laterally by the vesicosacral (uterosacral) folds in females and the sacrogenital folds in males
• Subperitoneal compartment


  Bounded between the peritoneum superiorly and the parietal sheet of the pelvic fascia below
• Retropubic (prevesical) space


  Located between the symphysis pubis and the anterior border of the bladder and prostate gland in males
• Rectovesical space


  Inferior to the rectovesical pouch, located posterior to the urinary bladder and prostate, and anterior to the distal third of the rectum (extraperitoneal part)
• Retrorectal space


  Between the visceral and parietal layers of the pelvic fascia, covering the rectum and the sacrum, filled with loose connective or fat tissue
• Parametrium


  Located around the cervix of the uterus, laterally within double-layered broad ligament, containing the uterovaginal venous plexus, vegetative plexus, uterine artery and ureter
• Perineum


  • A diamond-shape space whose boundaries are the lower border of symphysis pubis, rami of pubis and ischium, ischial tuberosity, sacrotuberous ligament, and tip of coccyx
• Contents of the female perineal region

  • Deep perineal pouch: proximal urethra, deep transverse perineal muscle, inferior part of external urethral sphincter, urethrovaginal sphincter and compressor urethrae muscle, dorsal nerves and vessels of the clitoris
  • Superficial perineal pouch: roots of the erectile tissues (corpora cavernosa, bulbs of the vestibule), bulbospongiosus, ischiocavernosus, superficial transverse perineal muscles
• Contents of the male perineal region

  • Deep perineal pouch: perineal part of the urethra, deep transverse perineal muscle, inferior part of external urethral sphincter, bulbourethral glands, dorsal nerves and vessels of the penis
  • Superficial perineal pouch: root of the penis (corpora cavernosa, corpus spongiosum), bulbospongiosus, ischiocavernosus, superficial transverse perineal muscles
• Perineal central tendon


  Mass of connective, skeletal and smooth muscle tissues found between the anal and urogenital triangles, anchoring most of the perineal muscles
• Muscles of the perineal region

  • Sphincter ani externus
  • Levator ani
  • Superficial transverse muscle of perineum
  • Deep transverse muscles of perineum
  • Bulbocavernosus
  • Sphincter of urethra (male) or urethrovaginal sphincter (female)
  • Perineal central tendon
• Fascial layers of the urogenital region

  • Superior fascia of urogenital diaphragm
  • Inferior fascia of urogenital diaphragm
  • Superficial fascia of perineum (Colles' fascia)
  • Deep perineal space
  • Superficial perineal space
  • Fascia of the penis
  • Scarpa's fascia
  • Dartos of the scrotum
• Ischiorectal (ischioanal) fossa


  Bilateral triangular spaces inferior to the rectum and anus, formed by the obliquely coursing levator ani muscle and the inferior fascia of the pelvic diaphragm
• Anal sphincters


  Internal: smooth muscle, surrounds upper two-thirds of anal canal, autonomic nerve supply

  External: striated muscle, surrounds lower two-thirds of anal canal, three parts - subcutaneous, superficial and deep, innervated by anal nerves of pudendal nerve and branches of S4
• Anorectal ring


  At the junction of rectum and anal canal, consisting of thickened muscle, contributing structures include puborectalis, superficial and deep parts of sphincter ani externus, and sphincter ani internus