Boobology 101: Basic Anatomy

To better visualize what’s inside the ‘girls,’ think of a grapefruit half, upside-down on a plate, with its sections arranged in a dome-shaped circle around the center point.  In the case of your breast, 15-20 ‘lobes’ of glandular tissue radiate out from the nipple like spokes on a wheel.

If we take a closer look at the lobes, they are made up of many tiny grape-like structures (yep, more fruit!) called globules, where breast milk is actually produced.  Rich fat deposits in and around the globules give shape (curves!) and protection to the whole breast. In fact 3-4% of your total body fat is stored here, which is why your cup size can shift a lot when you gain or lose even a few pounds.

Your breasts (a.k.a. mammary glands) are actually rather loosely attached to the chest wall! There’s no strong outer layer of muscle to support and snug them in them like you have for your stomach and intestines—your pecs lie underneath your breasts so are pretty useless when it comes to lending support. 

Instead, some fairly wimpy interwoven connectors called "Cooper's Ligaments" help hold the breast lobes together and in place on your chest wall (but provide only a modest bit of actual ‘support’). Unfortunately for long-term perkiness, they aren't true ligaments like the strong bands that connect your muscles to your bones, but are skinny and easily stretched.  So your outer skin layer ends up as the other main source of natural support and shape for your breasts.

If the idea of relying on your skin for major breast support sounds a little scary, seeing it captured and replayed on film, as I have in my research lab, is even more frightening! Slo-mo action of nude breasts during running clearly shows that constant, repetitive—even extreme—stretching occurs when breasts don't have support!  

As with skin anywhere else on your body, too much continual stress and stretching contributes to permanent sagginess. Think of what happens to the size and shape of earlobes when a woman wears large, heavy earrings over a period of years—you get the picture! But no reason to stay scared:  My lab research also shows that a highly supportive sports bra can greatly minimize the short-term motion and stretching that accelerates long-term sagging.

So don’t let fear of sagging or damaging your breasts keep you out of the gym—if you want to put excess motion on hold, look for a sports bra with a “High” or “Maximum” motion control rating for your cup size and activity level. 

Staying active is one of the best ways to keep your breasts healthy, so grab a great sports bra and take the ‘girls’ for a well-deserved spin!

Have a great, fit week!

LaJean