Pelvis – overview

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Welcome

  • Osteology
    • The pelvic ring formed from 2 innominate bones
      • articulate posteriorly with the sacrum and anteriorly through pubis symphysis
    • Each innominate bone is composed of three fused bones: ilium, ischium, and pubis
      • ilium
        • Anterior superior iliac spine (ASIS)
        • Aneterior inferior iliac spine (AIIS)
        • Posterior superior iliac spine (PSIS)
        • iliopectineal eminence – region union between ilium and pubis
        • gluteal pillar
          • the anterior portion of the gluteus medius insertion and thickening of the iliac crest
          • important fixation pathway for fractures of the pelvis
        • sciatic notch
      • ischium
      • pubis
    • Stability
      • no inherent stability of articulations
      • stability comes from ligament complexes
    • Ligament complexes
      • posterior complex
        • sacroiliac ligaments
          • posterior stronger than anterior
        • iliolumbar ligaments
          • transverse process of L4/L5 to posterior ilium
      • anterior complex
        • pubis symphysis
          • a fibrocartilaginous disc between innominate bones
      • pelvic floor complex
        • sacrospinous ligament
          • transversely oriented
          • resists external rotation
        • sacrotuberous ligaments
          • longitudinally oriented
          • resists vertical translation