What is the main difference between the pelvic brim in females and males?

Explanation

### Step-by-Step Solution:

1. **Understanding the Pelvic Brim**: The pelvic brim is the edge of the pelvic inlet, which is the upper opening of the pelvis. It plays a crucial role in distinguishing male and female pelvises.

2. **Shape Differences**: The pelvic brim in females is generally wider and more circular in shape, while in males, it is narrower and more heart-shaped. This difference is primarily due to the adaptations for childbirth in females.

3. **Pelvic Angle**: The angle of the pelvic arch is another significant difference. In males, the pelvic arch is typically less than 90 degrees, whereas in females, it is more than 100 degrees. This wider angle in females facilitates the passage of a baby during childbirth.

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