| MadSci Network: Anatomy |
What is the anatomy behind being short waisted?
A short waist, or a seemingly shorter distance between the bottom of the ribcage and the top of the pelvis, is more a statement of tailoring or fashion than it is of anatomy. An example of this is the difference between in the waist of a man and a woman. Men tend to wear the top of their pants low, so that their belt buckle lies below their umbilicus (belly button). Women tend to wear the top of their pants high, so that their belt buckle lies above their umbilicus. Because of this, many people would claim that men have a lower waist than women, even though there is no important anatomical difference here (for both men and women the umbilicus is located at about the level of the 4th lumbar vertebra). Fashion sense and clothing design are the primary determinants of where the waist is located. When I was involved with clothing design for the Army, we had two different definitions of the waist. The top of the iliac crest (or pelvis) corresponded well with how men wear clothes, and would therefore be the male waist. The natural lateral (side) indentation of the abdominal region corresponded well with how women wear clothes, and would therefore be the female waist. Both men and women were measured for these values.
Nearly everyone has about a hand’s breadth of distance between the top of their pelvis (the iliac crest) and the bottom of their ribcage (the 12th rib). A long ilium (top of the pelvis) or changes in the size and shape of the ribcage would change that, but the variation here is not as much as you might think. More important is the amount and distribution of body fat. The lateral indentation of the abdominal region (female waist) is mostly determined by how fat is distributed in that region. This distribution can vary quite a bit between individuals.
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