Ob/GYN Station 1

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1. Objectives

1. Identify common bony landmarks for the purpose of anatomical orientation of the pelvis.
2. Distinguish between pelvic inlet and outlet and the significance of these 2 structures with respect to positioning of the fetal head.
3. Characterize the shapes of the pelvis and the significance for predicting ease of parturition.
4. Determine common pelvic measurements useful in characterizing pelvic shape and anticipating problems during labor.
5. Identify the subpubic angle and understand the course of neonate during parturition.
6. Review the components of the skull to appreciate the size and shape of the fetal head during delivery.
7. Understand the fontanelles and their use in in assessing the health status of the fetus.

2.  Relevant Anatomy

• Bony pelvis– sacrum, coccyx, ilium, ischium, pubis
• Linea terminalis (true and false pelvis), (pelvic inlet and outlet)
• Ligaments of the pelvis (sacrospinous ligament, sacrotuberous, anterior longitudinal
  • ligament of the sacrum)
• Round ligament, Broad ligament, Cardinal and Uterosacral ligament
• Shapes of the female pelvis– gynecoid, anthropoid, android, platypelloid
• Pelvic Conjugates and Diameters
  • Obstetric conjugate
  • Diagonal conjugate
  • Transverse diameter
  • Interspinous diameter
• Bones of the skull including sutures

3.  Case 1

Ms. Osteo is a 28 yo G1P0 at 39w0d by LMP consistent with 8-week ultrasound who was admitted for early labor. She progressed to complete cervical dilation and the fetal head is at 0 station and direct occiput posterior. She then begins to push.