Exam

Pelvimetry

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Pelvimetry, Caldwell-Moloy Pelvis Classification, Diagonal conjugate, Intertuberous Diameter

  • Efficacy
  1. Pelvimetry is a poor predictor of who will deliver vaginally and is not routinely performed nor recommended in the U.S.
  • Physiology
  • Caldwell-Moloy Classification
  1. Gynecoid Pelvis (50%)
    1. Pelvic brim is a transverse ellipse (nearly a circle)
    2. Most favorable for delivery
  2. Android Pelvis (Male type)
    1. Pelvic brim is triangular
    2. Convergent Side Walls (widest posteriorly)
    3. Prominent ischial spines
    4. Narrow subpubic arch
    5. More common in white women
  3. Anthropoid Pelvis
    1. Pelvic brim is an anteroposterior ellipse
      1. Gynecoid Pelvis turned 90 degrees
    2. Narrow ischial spines
    3. Much more common in black women
  4. Platypelloid Pelvis (3%)
    1. Pelvic brim is transverse Kidney shape
    2. Flattened gynecoid shape
  • Exam
  • Determination of an Adequate Pelvis
  1. Diagonal conjugate
    1. Distance from sacral promontory to symphysis pubis
    2. Approximate length of fingers introitus to Sacrum
    3. Adequate Diagonal conjugate > 11.5cm
    4. Images
      1. ObPelvimetryDC.jpg
  2. Intertuberous Diameter
    1. Distance between Ischial tuberosities
    2. Approximately width of fist
    3. Adequate Intertuberous Diameter > 10 cm
    4. Images
      1. ObPelvimetryIT.jpg
  3. Prominence of ischial spines