Avascular Spaces of the Pelvis (Where the blood vessels are not!!!)

Avascular Spaces Potential spaces—filled with fat and connective tissue Eight spaces: (four midline and four lateral) Lateral spaces: Pared pararectal and paravesical spaces (both can be used to ligate hypogastrics) Midline spaces: Prevesical space, vesicouterine space, rectouterine space, retrorectal space Each pelvic organ can be separated from the others by opening avascular spaces.

Endopelvic Fascia The endopelvic fascia is a meshwork of connective tissue and smooth muscle which connects the pelvic viscera to the pelvic side walls. It also serves as a conduit for blood vessels and nerves. The fascial planes enable skilled surgeons relatively bloodless access to the pelvic organs and pelvic floor

The Space of Retzius (Prevesical space) Is entered by perforating the transversalis fascia lower boundary: Levator ani and pubic bone upper boundary: rectus abdominis Lateral boundary: levator ani, and obturator internus fascia and the Arcus tendineus fascia pelvis. Contents Plexus of Santorini Bladder and urethra Obturator canal(watch for obturator branch of external iliac)

Vesicovaginal or Vesicouterine space Lower boundary: proximal third of the urethra Upper boundary: anterior cul-de-sac Lateral boundary: pelvic side wall and broad and cardinal ligaments Posterior boundary: uterus and vagina Anterior boundary: Bladder and proximal urethra Contents Ureters!!!!

Rectovaginal Space Distal boundary: perineal body Upper boundary: Posterior Cul-de –sac Lateral boundaries: fascia of the levator ani and uterosacral ligaments Floor : Coccygeus muscle Anterior boundary: vaginal muscularis Posterior boundary: rectal muscularis Contents Rectal pillars Sacrospinous ligaments Utero sacral ligaments

Retrorectal Space (pre sacral space) Upper border: bifurcation of the aorta Lower border: sacrum Lateral border: internal iliac arteries Contents Middle sacral vessels Lateral sacral vessels Presacral nerves

Bilateral Paravesical Spaces Lower border: fascia of the levator Ani Medial border: Obliterated Hypogastric artery Lateral border: external iliac artery Posterior border: Broad ligament Anterior border: Pubic symphysis Contents Hypogastric artery Ureter

Bilateral Pararectal Spaces Floor: coccygeus muscle Medial boundary: Ureter Lateral boundary: hypogastric artery Anterior boundary: broad ligament Posterior boundary: sacrum Contents Ureter Hypogastric artery

Caution Hazardous areas !!! Prevesical space: injury to Plexus of Santorini, obturator vessels or nerve (Corona mortis) Vesicovaginal space: injury to the bladder or urethra Rectovaginal space: damage to the rectosigmoid, Retro rectal space: injury to the aorta or common iliacs, middle or lateral sacral vessels, nerve plexus injury Paravesical spaces: injury to the bladder, or broad ligament external iliac vessels (vein), obturator vessels or nerves, ureter Pararectal spaces: injury to ureter, hypogastic vessels (vein)