North American Registry of Midwives (NARM) Practice Exam

How many bones make up the pelvis?

1. Two

2. Three

3. Four

4. Five

The correct answer is: Four

The pelvis is primarily composed of three major bones: the left innominate (hip bone), the right innominate, and the sacrum. The innominate bones are each formed from the fusion of three components—the ilium, ischium, and pubis—making the total number of bones contributing to the pelvic structure more nuanced, but they are collectively categorized as forming three main segments of the pelvic girdle. The pelvis functions as a critical structure in human anatomy, providing support for the weight of the upper body, allowing for bipedal movement, and serving as a protective enclosure for the pelvic organs. Understanding the composition of the pelvis is essential, especially in midwifery, as it plays a significant role during childbirth, influencing factors such as the width of the birth canal and the positioning of the fetus. The answer reflects the collective comprehension of the pelvis's work as a unit made of three primary bones, despite the intricacies involved in its structure.