Bra Science — Center full? Outer full? Splayed? What does it all mean?

With the recent advent of increasing discussion on center fullness and outer fullness - including a gore alteration that increases center depth, and more and more people being confused as to what it all means, I thought I'd try and explain what these shapes are and why so many people struggle to figure out which they have.

Fullness on top and bottom (or "vertical fullness distribution" as I like to pretentiously say) has been a staple of English-speaking bra fitting forums for years, but horizontal fullness distribution has only ever really been mentioned since about 2015, starting off with this amazing blog post by Brastic Measures. I'm noting now that as with top and bottom fullness, horizontal fullness is a spectrum. You can be extremely outer full, even, or extremely center full - or anything in between.

Center fullness and outer fullness can both be mistaken for a splayed shape.

Yup, two polar opposites can and are both mistaken for a third, unrelated, shape - not just by newbies to bra fitting but by bra retailers who write shape guides. But how can that be?

1. What is a splayed shape?

Splayedness is an aspect of root shape. The breast root is the part where your breast attaches to your chest - no matter how you position your breasts, your root will stay the same. Companies usually make bras that suit UU shaped breasts, whereas a splayed shape attaches to the breast wall like (_/\_). This means that most people with this shape will have gaping near the gore here:

Some people with this shape struggle with creating "kissing" cleavage if they desire it.

People who have splayed roots may be center full, outer full or have even horizontal fullness - root shapes have no bearing on fullness.

2. What do center full and outer full shapes look like and what do they truly mean?

A center full shape is, as you may guess, one where a lot of breast tissue can be found in the center, between the nipples. When leaning forwards this shape is likely to look like this:

Some people with a center full shape have outwards facing nipples when leaning forwards, others have nipples that point straight down. Any combination of nipple positioning and size and shape can occur.

Fit issues that can arise from center full shapes include the sheer power of the boob pushing a gore outwards, spilling out of the middle of plunges (and spilling out in stretch lace bits that go near a gore on balconettes/bras with more coverage), gaping on the sides of the bra cup, and wires being pushed down - especially near the gore.  People who have center full breasts can sometimes think their breasts are close-set due to the gore not tacking, but really they just have a lot of tissue right next to the gore. Not that people who have center full breasts can't also have close set breasts...

People with center fullness don't often have difficulty creating "kissing" cleavage if they desire it, unless another shape aspect prevents it.


An outer full shape is the opposite - a lot of breast tissue can be found on the outsides of the nipples. When leaning forwards, this shape is likely to look like this:

Some people with an outer full shape have inwards facing nipples when leaning over, but others have nipples that point straight down.

Fit issues that can arise from outer full shapes include gaping near the gore, breast tissue being squashed in the outer halves of cups, and (I have only seen this once and it hasn't been confirmed but I believe it can exist) spillage out of wires that aren't necessarily too wide. The outer halves of the wires may also be pushed down. Some people with outer fullness have difficulty creating "kissing" cleavage if they desire it.


A really outer full shape can cause the bra size calculator (and other measurement techniques) to overestimate cup size (as there is less volume than expected in the center), and a really center full shape can cause the calculator to underestimate cup size (as there is volume that isn't measured).

3. So why can both of these be mistaken for a splayed shape?

Well, when leaning forwards it becomes apparent what is happening, especially when people have a more projected breast shape. But what do these shapes look like when standing up?

A center full shape can often cause the nipples to point outwards, giving the breasts the appearance of splayedness.

An outer full shape often doesn't have much tissue in between the nipples, so it can look like the "weight" of the boob is on the outer halves of the chest, giving (again) the appearance of splayedness.

As always, this is just an example. How breasts act when unsupported doesn't have huge bearing on how they act when supported, hence why center and outer fullness can so easily be mistaken for splayedness.

So there we go, hope that cleared things up for you :) - if you have any questions or concerns please comment and I'll get back to you as soon as I can. Huge thanks to /u/noys for making all these graphics and dealing with how demanding I am!

Now all we need is a definitive guide for which bras suit which horizontal fullness trait...

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