The skeletal system is the support for the body. It protects the organs and provides anchoring for ligaments, tendons, and muscles that allow movement. Although both male and female skeletal systems contain the same number of bones, there are differences between them. Differences between the skeletal systems of men and women are structural and include areas such as the pelvis, skull, and limbs. The mass and development of bones are two additional areas of difference in the skeletal systems.
One of the areas of difference between male and female skeletal systems is the pelvis. A female’s pelvic bone and pelvic region are shaped differently than a male’s, as the pelvic region of a female is made to allow for the process of childbirth. Female pelvic regions are more circular and the pelvic bone is smaller and wider. Male pelvic cavities, in contrast, are not as shallow.
Structural differences between the male and female skeletal systems are also evident in the skull. A small protruding part found on the back of the skull, called the external occipital protuberance, is more evident on the male skull than the female skull. Jawbones of the female skull are also more rounded, while the male jawbone is squarer. The brow bones of a female skull are not as pronounced as those of the male skull. These aspects create distinguishing features that create visual differences in the male and female facial structures.
Bones that make the limbs of skeletons also show differences between the skeletal systems of men and women. The ulna, radius, and humerus are the three bones that make the arms, while the fibula, tibia, and femur are the leg bones. In males, these bones are generally longer and thicker than they are in females. Finger bones, called phalanges, are also usually larger in males than in females. Some men, however, have shorter bones than females.
Overall mass contributes to the difference between male and female skeletal systems. Male skeletons are often heavier and much larger. Although the mass of a skeleton can be a general reference point, it cannot be used alone. There are some men who are smaller than average and will have smaller skeletons. Additionally, there are some women with larger than average skeletons. In order to determine whether a skeleton is male or female, the other major differences must be considered, along with genetics and ethnicity.
Differences between the male and female skeletal systems are also influenced by bone development. Hormones play a large role in the growth of bones. For males, testosterone is the hormone that affects bone growth and shape, while the female hormone that influences bone development is called estrogen. During puberty, estrogen levels are much higher for females and testosterone levels for males, causing female bones to stop developing by age 18 and male growth to stop by age 21.