Objectives 2.5 Pelvis and perineum

Osteology

Hip bones:

  • Ilium
  • Ischium
  • Pubis
  • Acetabulum
  • Sacrum
  • Obturator foramen
  • Greater sciatic notch
  • Lesser sciatic notch
  • Superior pubic ramus
  • Inferior pubic ramus
  • Ischiopubic ramus
  • Ischial spine
  • Ischial tuberosity
  • Iliac crest
  • Anterior superior iliac spine
  • Anterior inferior iliac spine
  • Posterior superior iliac spine
  • Posterior inferior iliac spine
  • Pubic arch (subpubic angle = angle of pubic arch; wider in females than males)
  • Pelvic cavity (true pelvis)
  • Pelvic inlet (superior pelvic aperture)
  • Pelvic brim
  • Pelvic outlet
  • Greater (false) pelvis
  • Lesser (true) pelvis

Sacrum:

  • Sacral promontory
  • Anterior and posterior sacral foramina

Coccyx

 

Ligaments

  • Sacrotuberous ligament
  • Sacrospinous ligament

 

Pelvic floor and cavity walls

  • Levator ani muscle
    • Puborectalis
    • Pubococcygeus
    • Iliococcygeus
  • Urogenital and anal hiatus
  • Obturator internus muscle
  • Piriformis

 

Female Pelvic Hemisection

  • Vesicouterine (uterovesical) pouch
  • Rectouterine pouch (Pouch of Douglas; Cul-de-sac of Douglas)
  • Ovary
  • Uterine tube and parts of uterine tube
    • Infundibulum with fimbriae
    • Ampulla
    • Isthmus
  • Uterus and parts of uterus
    • Fundus and horns (cornua)
    • Body
    • Cervix
      • Internal and external os
  • Uterine cavity
  • Cervical canal
  • Vagina and vaginal fornix (anterior, 2 lateral, posterior)

 

Ligaments of the Female Pelvis

  • Suspensory ligament of ovary containing ovarian vessels
  • Ovarian ligament
  • Round ligament of uterus
  • Broad ligament of uterus (mesosalpinx, mesovarium, mesometrium)

 

Bladder and Rectum

  • Bladder
  • Retropubic (prevesical) space
  • Parts of the bladder
    • Body
    • Fundus
    • Apex
    • Neck
  • Detrusor muscle of bladder wall
  • Internal urethral sphincter
  • Trigone bounded by
    • Internal urethral orifice and
    • Orifices of the ureters
  • Rectum
  • Anorectal junction
  • Anal canal
  • Anal columns
  • Pectinate line
  • External anal orifice

 

Male Pelvic Hemisection

  • Urethra (prostatic, membranous and spongy)
  • External urethral orifice
  • Ductus deferens (vas deferens; note relationship with ureter)
  • Seminal gland (vesicle)
  • Ejaculatory duct
  • Prostate
  • Rectovesical pouch

 

Vasculature of the Pelvis

  • Common iliac artery
  • External iliac artery
  • Internal iliac artery
    • Umbilical artery
    • Obturator artery
    • Superior vesical arteries
    • Inferior vesical arteries
    • Uterine artery
    • Vaginal artery
    • Middle rectal artery
    • Internal pudendal artery
    • Superior gluteal artery
    • Inferior gluteal artery

Nerves of the pelvic cavity

  • Sacral plexus (L4-S4)
  • Lumbosacral trunk (L4, L5)
  • Obturator nerve (L2-L4)
  • Pudendal nerve (S2, S3, S4)

 

Boundaries of the Perineum

  • Anterior: pubic symphysis
  • Antero-lateral: ischiopubic rami
  • Lateral: ischial tuberosities
  • Postero-lateral: sacrotuberous ligaments
  • Posterior: coccyx

 

Triangles

  • An imaginary line running between the ischial tuberosities divides the perineum into triangles:
    • Anterior: urogenital triangle
    • Posterior: anal triangle

 

Anal Triangle:

  • Perineal body
  • Anal orifice
  • Ischioanal (ischiorectal) fossa and boundaries:
    • Medial: levator ani
    • Lateral: obturator internus
  • Pudendal nerve and branches
    • Inferior rectal (anal) nerves
    • Perineal nerve
    • Dorsal nerve of the clitoris / Dorsal nerve of the penis
  • Internal pudendal artery
    • Inferior rectal artery
    • Perineal artery
    • Dorsal artery of the clitoris / Dorsal artery of the penis

 

Female external genitalia:

  • Bulb of the vestibule (paired)
  • Three paired muscles
    • Bulbospongiosus muscle
    • Ischiocavernosus muscle
    • Superficial transverse perineal muscle
  • Labia majora
  • Labia minora
  • Vestibule of the vagina (area between labia minora)
  • Clitoris
  • External urethral orifice
  • Vaginal orifice

 

Male external genitalia and superficial perineal pouch

  • Corpus spongiosum
  • Corpora cavernosum
  • Paired muscles
    • Bulbospongiosus muscles
    • Ischiocavernosus muscles
  • Parts of the penis
    • Root
    • Crus of the penis (continuous with corpus cavernosum)
    • Bulb of the penis (continuous with corpus spongiosum)
    • Body (shaft)
    • Dorsal & ventral surfaces
    • Glans penis
  • External urethral orifice
  • Superficial dorsal vein of penis
  • Deep dorsal vein of penis
  • Dorsal artery of penis
  • Deep artery of penis
  • Dorsal nerve of penis

 

Clinical Correlations

  • Tear/rupture of the perineal body
  • Episiotomy
  • Pudendal nerve block
  • Digital rectal examination
  • Benign prostatic hypertrophy
  • Measuring obstetric and diagonal conjugate
  • Hysterectomy and the significance of positioning between the uterine artery and ureter
  • Rupture of Urethra in Males and Extravasation of Urine
  • Prostate cancer
  • Uterine prolapse
  • Role of autonomic nerves in male erection and ejaculation
  • Role of posterior vaginal fornix with Culdoscopy