Pelvis Flashcards
(41 cards)
Female versus male pelvis
Female: Wider and broader, lighter in weight Oval shaped inlet Less prominent ischial spines Greater angled sub-pubic arch Short sacrum Less pronounced sacral promontory
Borders of pelvic inlet
Posterior: sacral promontory, sacral ala
Lateral: arcuate line on inner surface of ilium, pectineal line on super pubic rami
Anterior: pubis symphysis
Borders of pelvic outlet
Posterior: tip of coccyx
Lateral: ischial tuberosoities, inferior margin of sacrotuberous ligaments
Anterior: pubic arch (inferior border of ischiopubic rami)
Borders of Greater sciatic foramen
Anterolateral: greater sciatic notch
Superior: anterior sacroiliac ligament
Inferior : sacrospinous ligament and ischial spine
Posteromedial: sacrotuberous ligament
Contents of greater sciatic foramen
Superior gluteal artery, vein, nerve Piriformis muscle Inferior gluteal artery, vein, nerve Internal pudendal nerve Nerve to obturator internis Nerve to quadrates femoris Posterior femoral cutaneous nerve Sciatic nerve
Borders of lesser sciatic foramen
Superior: sacrospinous ligament and ischial spine
Anterior: ischial spine, lesser sciatic notch and ischial tuberosity
Posterior: sacrotuberous ligament
Contents of the lesser sciatic foramen
Internal pudendal artery and vein
Pudendal nerve
Obturator internis
Nerve to obturator internis
Anatomic borders of the perineum
Anterior: pubis symphysis Posterior: tip of coccyx Laterally: inferior pubic rami, inferior ischial rami, sacrotuberous ligaments Roof: pelvic floor Base: skin and fascia
Surface borders of the perineum
Anterior: mons pubis in females, base of penis in males
Lateral: medial surface of thigh
Posterior: superior end of intergluteal cleft
Contents of the perineum
Anal triangle
Urogenital triangle
Contents of anal triangle
Anal aperture
External anal sphincter
Ischioanal fossa (x2)
Layers of urogenital triangle
Deep to superficial Deep perineal pouch Perineal membrane Superficial perineal pouch Perineal fascia - Deep: Colles' fascia, continuous with Scarpa's fascia - Superficial, continuous with camper's Skin
Perineal body
Irregular fibromuscular mass Located at junction of urogenital and anal triangles Central point of perineum Acts as attachment of muscle fibres: Levator ani Bulbospongiosus Superficial and deep perineal muscles External anal sphincter External urethral sphincter
Blood supply to perineum
Internal pudendal artery
Innervation to perineum
Pudendal nerve (S2-4)
Pelvic floor muscles (pelvis diaphragm)
Levator ani muscles (pubococcygeus, puborectalis, iliococcygeus)
Coccygeus
Levator ani muscles
3 separate paired muscles (pubococcygeus, puborectalis, iliococcygeus)
Innervated by anterior rami of S4 (pudendal nerve)
Attachments:
Anterior: pubic bodies of pelvic bone
Lateral: thickened fascia of obturator internis, known as tendinous arch
Posterior: ischial spines of pelvic bones
Puborectalis
U-shaped
From bodies of pubic bones past urogenital hiatus around anal canal
Tonic contraction creates anorectal angle: maintaining faecal continence
Pubococcygeus
Arise from body of pubic bone and anterior aspect of tendinous arch
Travel around urogenital hiatus and run posteromedially, attaching to coccyx and anococcygeal ligament
Iliococcygeus
Thin muscle fibres
Start anteriorly at ischial spines and posterior aspect of tendinous arch
Attach posteriorly to coccyx and anococcygeal ligament
Coccygeus
Innervated by anterior rami of S4/S5
Origin: ischial spine
Insertion: lateral aspect of sacrum/coccyx
Bifurcation of common iliac
Creates internal/external iliacs
Approx L5-S1
Internal iliac: path
Descends from bifurcation into lesser pelvis
Medial to external iliac vein and obturator nerve
At superior border of greater sciatic foramen it divides into anterior and posterior trunks
Internal iliac: anterior trunk branches
Obturator artery Umbilical artery Inferior vesicle artery Vaginal artery Uterine artery Middle rectal artery internal pudendal artery Inferior gluteal artery
