Page 21 - 2023 Elctronic Book (3) Normal Labor_Neat

• from the tip of the coccyx to the lower border of symphysis pubis.

o Obstetric antero-posterior diameter = 13 cm

• From the tip of the sacrum to the lower border of symphysis pubis

as the coccyx moves backwards during the second stage of labor.

• Transverse diameters:

o Bituberous diameter = 11 cm

• Between the inner aspects of the ischial tuberosities.

Types of pelvises

 Pelvis has been classified into four types: (Figure 5)

1) Gynecoid: Rounded brim

2) Android: Heart shape

3) Anthropoid: Oval brim

4) Platy-pelloid: Kidney shaped brim.

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