North American Registry of Midwives (NARM) Practice Exam

If ischial spines cannot be felt, which type of pelvis may the woman have?

1. Android

2. Anthropoid

3. Gynecoid

4. Platypelloid

The correct answer is: Gynecoid

When ischial spines cannot be palpated during a pelvic examination, it is most indicative of a gynecoid pelvis. This type of pelvis is characterized by a more rounded shape, providing a wider pelvic inlet and outlet, which generally allows for easier passage of the fetus during childbirth. In a gynecoid pelvis, the ischial spines are less prominent because of the pelvic shape and its broader dimensions compared to other pelvic types. In contrast, the Android pelvis is more heart-shaped and has more prominent ischial spines, making it more likely that those structures would be palpable. The anthropoid pelvis has an elongated, oval shape, with a more narrow outlet, and the ischial spines could still potentially be felt. Lastly, the platypelloid pelvis is wide and has a flatter shape, but its characteristics would still allow for the identification of ischial spines. Thus, the ability or inability to feel the ischial spines is vital in determining the type of pelvis and is clearly aligned with the defining features of a gynecoid pelvis.