Uterus

Overview

• Body (corpus) : Upper 2/3 of uterus

  • Fundus: Superior to ostia of fallopian tubes

• Cervix : Lower 1/3 of uterus

  • Isthmus: Junction of body and cervix

• Parametrium : Tissue immediately surrounding uterus

• Myometrium : Smooth muscle forming bulk of uterus

• Endometrium : Composed of 2 layers

  • Stratum basalis attached to myometrium, does not change

  • Stratum functionalis: Thicker, varies with cycle

• Uterus is extraperitoneal in midline of true pelvis

• Uterine position

  • Flexion is axis of uterine body relative to cervix

  • Version is axis of cervix relative to vagina

  • Anteversion ± anteflexion is most common

• Peritoneum extends over bladder dome anteriorly and rectum posteriorly

  • Vesicouterine pouch (anterior cul-de-sac) : Anterior recess between uterus and bladder

  • Rectouterine pouch of Douglas (posterior cul-de-sac) : Posterior recess between vaginal fornix and rectum; most dependent portion of peritoneum in female pelvis

• Supporting ligaments

  • Broad ligaments: Extend laterally to pelvic wall and form supporting mesentery for uterus

  • Round ligaments: Arise from uterine cornu and course through inguinal canal to insert on labia majora

  • Uterosacral ligaments (posteriorly), cardinal ligaments (laterally), and vesicouterine ligaments (anteriorly) form from connective tissue thickening by cervix

• Fallopian tubes connect uterus to peritoneal cavity

  • 4 segments: Interstitial (portion going through myometrium at cornua), isthmus, ampulla, infundibulum

• Arteries : Dual blood supply

  • Uterine artery (UA) arises from internal iliac artery, anastomoses with ovarian artery

    • –

      UA crosses over the ureter and enters uterus just above cervix

  • Arcuate arteries arise from UAs; seen in outer 1/3 of myometrium → radial arteries → spiral arteries (endometrium)