Choosing between submuscular & subglandular breast implants.

Although we’re primarily a breast implant sizing service, we get asked a lot of other questions by our patients. One of the more common questions is “which are better, subpectoral breast implants or subglandular breast implants?” Usually that question is closely followed by ‘what is dual plane?”
The short (and very generalised) answer is: Submuscular is used in younger, skinnier women, with little natural breast tissue, having round implants, and wanting a more natural look. Subglandular is used in patients who have had children, those with more natural breast tissue, those with some breast ptosis or droopiness, and those having anatomical implants. Dual plane is a surgical technique combining both options, in an attempt to get the best of both worlds.

The long answer is, as usual, very long, and involves figuring out which option is best for you.

The basics.

Breasts are made of layers, firstly skin on the outside, and a mixture of fat and glandular tissue (that makes milk) on the inside. Underneath the breast is the pectoralis major (usually shortened to ‘Pec’) muscle, and underneath the pec is the rib cage.

Putting breast implants inside your body involves making a small incision, and then through that incision splitting (dissecting) apart two of the layers. Splitting apart the layers creates a space (the pocket or cavity) that the breast implant sits in.

The first main option is to split apart the glandular tissue from the pec muscle. This creates a subglandular pocket. On the good old internet, this is also called ‘overs’ or ‘on top’. The second main option, splitting apart the pec muscle from the ribcage underneath, creates a submuscular pocket. ‘Subpectoral’ to experts (you’ll notice I use both terms interchangeably **), ‘unders’ on the forums!

Now it’s very likely that your surgeon is going to pretty much tell you ‘which you need’. Personally, once I’ve decided with a patient on implant size, shape, technique etc, and asked them about their goals and their exercise regime, I generally just tell them ‘this is what you’re getting’. But it is definitely worthwhile trying to explain the complex calculations that go on in a plastic surgeon brain, so read on!

** This is actually incorrect. Technically, a ‘submuscular’ pocket refers to putting the entire implant underneath the pec muscle and some other muscles. Technically a ‘subpectoral’ pocket refers to putting the top 1/3 to 2/3 of the implant underneath the pec and the bottom part is not underneath any muscle. But for SEO purposes I’m using both terms in this post.

Why subpectoral breast implants are best. Maybe.

The critical advantage of submuscular breast implants is that it makes the breast look less fake. (At least in photos, at rest.)

This is because the thing that makes breasts look ‘fake’ is the ‘shelf effect’, where the top edge of the implant is noticeable. From side on you see the collarbone, and the chest below it is flat, and then boom, the breast starts. The thinner your skin and fat and glandular tissue sitting on top of the implant, (i.e. the closer to the outside world that implant is), the more you will be able to see the shape of the implant and especially the top edge of it.

The pec muscle is anywhere from 1cm to 5cm thick, and if you have got skin, fat, glandular tissue plus 2cm of Pec muscle sitting on top of your implant, that extra 2 cm will make the top edge of the implant much less visible to the outside world. The Pec muscle actually only covers the top half of the implant, because of the triangular shape of that muscle. This has the bonus effect of ‘squishing’ the top half of the implant and pushing the volume down into the bottom half of the implant, which creates a more teardrop, natural, less noticeable top edge.

If you’ve already got 5cm of skin fold thickness and/or breast tissue covering over the top edge of your implant, the extra 2cm of Pec muscle won’t make any difference, which is why this ‘shelf effect’ is only an issue in skinnier women with smaller existing breasts. And if you’re choosing a smaller implant, a lower profile, or an anatomical shape, the ‘shelf effect’ may not be an issue even in skinnier and smaller patients.

Less important advantages of subpectoral implants are a slightly decreased risk of capsule formation, and a slightly quicker surgery.

Disadvantages of subpectoral breast implants.

Choosing submuscular breast implants is not all good. Submuscular implants are more painful afterwards, the implants can move or ‘animate’ when you are working your Pec’s in the gym, and they are more prone to being slowly squeezed downwards and outwards from the original position that they were placed in.

The pectoralis major muscle attaches all along the edge of the sternum. This stops submuscular implants from being positioned close together in the midline, ie subpectoral implants have a wider ‘chest gap’. This can be minimised by releasing the pec muscle from it’s attachment to the sternum, and most good surgeons do this, even though doing so slightly increases the risk of bleeding after the surgery.

Overly large subpectoral implants will take longer to ‘drop and fluff’ compared with subglandular implants because the pec muscle will take time to stretch out. Frankenboob anyone?

Why subglandular breast implants are best. Maybe.

The critical advantage of subglandular breast implants is that they are better at stretching out loose skin.

Many women, after children, or weight loss, (or just ‘cos that’s what they got) have loose skin on the breasts. This causes droopiness (ptosis) and a generally unfavourable shape to the breast. These patients often don’t ask for bigger breasts per se. They mainly want their breasts to look perkier, fuller and more youthful.

A big part of achieving those goals is to replace ‘stuffing’ inside the ‘skin envelope’, to stretch out the loose skin. Using a really big implant will do that every time. But if you prefer a medium sized implant, putting that in a subglandular position means it is one layer closer to the skin you are trying to stretch out, and consequently it is going to stretch that skin slightly more than an implant which is subpectoral.

It is even more complex than that however. Subglandular allows more latitude for the surgeon to position the implant where it needs to be. Perhaps lower on the chest wall for patients with ‘low’ breasts. Perhaps closer together to each other for patients who want minimal ‘chest gap’ and maximal cleavage (for the size implant they chose).

Disadvantages of subglandular breast implants.

Overly large subglandular implants may actually weigh down the breasts, and over the years, cause the skin to stretch and the breasts to droop, more than a same size subpectoral implant would.

However this can also be a slight positive. Subpectoral implants, particularly textured implants which are ‘velcroed in place’ may not ‘drop’, or age, at the same rate as the natural breast tissue does. The implants may remain high and perky, whilst over years the natural breast tissue (if there is a reasonable amount to start with!) becomes more and more saggy in front of the implant, leading to a ‘waterfall effect’.

Subglandular implants may have a slightly higher risk of capsular contracture, although these days we believe there are a lot of other factors that are more important to minimise that risk.

Dual plane breast implants.

Dual plane breast augmentation was invented to sneakily get the advantages of both subglandular breast augmentation and subpectoral breast augmentation.  If you’ve read this far, you’re probably going to be interested in this separate post that explains it in detail.


The first thing to keep in mind is that a lot of the ‘issues’ you’ve just read about really only matter when you’re topless. In a bra, or in decent swimmers, the ‘issues’ disappear. You also need to keep in mind that the ‘issues’ which may be visible in the harshly lit flash still photography that surgeons use for before and afters, may not be very evident at all in real life.

Like always, ask your surgeon how often they use each technique. Fantastic results can be achieved with both subglandular or submuscular implants by an experienced surgeon. If the surgeon does 90%+ of their implants only one way, you might be suspicious that they’re not tailoring their surgery to each individual patient.

You can start to understand though, why we say sizing your implants accurately is so critical. Once you have decided on a size, and then the lesser factors of type and shape of implant, often the choice of using a subglandular or subpectoral pocket will be pretty obvious, at least to the surgeon who uses both techniques, and hopefully to you now that you’ve read this!


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