Can under the muscle implants initially cause breast size to appear smaller?

Great question. The answer is both yes and no. Much of this depends on whether the implants are placed totally under the muscle, or partially above and partially below (dual plane). Total muscle coverage makes the implants sit higher which can result in the breasts looking smaller. With dual plane,the implants sit relatively lower and look somewhat larger. This is the same explanation for why lifts make the breast look smaller even if we remove only skin.Subglandular implants might look bigger, but I would only recommend them if you have enough coverage with your existing breasts. Volume doesn't change much over time. However recent studies have shown that Submuscular implants result in the loss of some muscle volume over time,while Subglandular ones result in the loss of some native breast gland volume. Also have to consider that Submuscular implants may result in rib contour changes that make the breasts look smaller.Confusing enough? Rather than base your decisions solely on placement details, take on a more global viewpoint. Determine what you out want, and let your surgeon come up with potential solutions. My favorite tool is Vectra beast simulation which I perform for every augmentation patient. The more you know, the better you can communicate with your doctor and the better the result that they can give to you.

The pectoralis major muscle covers the upper and middle breast implant in an "under the muscle", or more accurately, "dual-plane" dissection. The muscle initially has a compressive effect on the implant making it appear smaller.  Over time, the implant will settle and "fluff out" as the muscle and soft tissues relax.  Although you will need to be a little more patient to see final results than with an "over the muscle" (subglandular) placement, the dual plane location will have more advantages for you such as a lower risk of capsular contracture, a more natural upper breast / cleavage appearance, and better soft tissue coverage.

That is correct. But it is only short lived. So, be patient and follow your PS recommendations. Happy healing!Best wishes and kind regards,Gary Horndeski M.D.

The volume of the implant obviously does not
change whether it is in front of the muscle (subglandular), or behind the
muscle (subpectoral). The "apparent
size" and shape of the breast
however may differ based upon implant location.

Breast implants placed over the top of the muscle are likely
to show more medial and upper edge definition and visibility, and perhaps more
projection.
Implant placement over the top of the muscle is
generally only preferred if there is sufficient thickness of the overlying
tissues. In the presence of thin skin, a thin subcutaneous layer, and a minimal
amount of breast tissue subglandular augmentation would not be desirable
because there will be an increased likelihood that the edge of the breast
implant may be visible and/or palpable; and there is also a greater likelihood
of visible and/or palpable wrinkling and rippling. Implants placed in a subglandular
position also have a higher risk of capsular contracture.
In the early post-op period following a
subglandular augmentation the skin and breast tissue do not pose a significant
resistance to the implant, and therefore the early breast shape will demonstrate
more projection and greater lower pole fullness.
However, following a submuscular augmentation,
the breast pocket is much tighter due to the muscle compressing the implant. As
a result, there is increased fullness of the upper breast, less projection
because the implant is being pushed against the chest wall by the muscle, and
the implant position appears higher. As the swelling decreases and the tissues
stretch, the implant 'settles' into place and the volume redistributes from the
upper portion of the implant to the lower portion. This results in a decrease
in the upper pole fullness and an increase in lower pole fullness and
projection.

Most breast implants placed in a submuscular position
demonstrate less medial and upper pole edge definition because the muscle
thickness provides an additional layer of camouflage. Most surgeons and
patients would consider this a benefit. The risk for capsular contracture is
also lower with a submuscular implant position.

I feel that the benefits of improved soft tissue coverage and
a lower incidence of capsular contracture experienced with the submuscular position almost always out-weigh
any potential benefits of the subglandular position.

Speak with your surgeon for more information about what is
best for you.

Thank you for your question.Although the size of the breast should not be different between an implant under the muscle and over the muscle, there are ways the size and shape may appear different.While the muscle is gradually descending, it is possible for the breast size to appear different because the implant will not be directly behind the breast tissue compared to above the muscle placement. Once the implant fully drops down, there should be no differences in size as the implant will be behind the breast tissue in both cases.Nevertheless, it is possible for there to be differences in shape of the breast when the implant is placed behind the muscle compared to above the muscle.When the implant is placed above the muscle (i.e., subglandular - directly behind the breast tissue), the implant can directly apply pressure on breast tissue to shape the breasts. This can allow the upper and inner breast areas to be filled more adequately. In fact, cleavage gap can be controlled more effectively. However, there are draw backs to above the muscle implant placement:Direct pressure on the breast tissue from large or high projecting implants may cause breast tissue wasting overtimeImplant may interfere with breast imaging and mammographyThere is often insufficient soft tissue coverage in the upper and inner sides of the breast and often fails to provide a natural superior poleImplant is exposed to endogenous bacteria in the breast tissue, resulting in higher rates of capsular contracture (the main reason why today most surgeons place their implants under the muscle)There are higher reoperation ratesThere is greater risk of symmastia (i.e., disappearance of cleavage) when cleavage gap is reduced too much and it can be difficult to correctPlease note that as a candidate for breast augmentation, subglandular implant placement may not even be an option if you do not have more than 2 centimeters of soft-tissue in the upper pole of the breast.These are reasons why the behind the muscle implant placement is the more preferred approach to maximize long-term soft-tissue coverage in breast augmentation.Hope this helps.

When an implant is placed under muscle, the muscle will be tight at first and not allow the volume of the implant to sit in its more natural position.  As it relaxes, the volume will shift into the lower pole more, filling out the breast tissue more like a regular breast.  Some patients call this "dropping & fluffing".  As the muscle relaxes, the volume drops ( not the implant, just the volume) and fluffs out the lower aspect of the breast.  This process can take anywhere form 1-3 months in most patients.  I hope this helps.

The shape of the breasts will change as the implants drop but the size will not change. The breasts will look more natural as the implants drop

Yes, you are correct. Initially the muscle compresses the implant and makes it look smaller. However once the implants drop there is no difference in size when copmpared to implants on top of muscle.

There is no significant difference between under the muscle versus over the muscle regarding breast size.The critical difference is the appearance of the upper pole of the breast and medial edge of the breast.I would recommend you view several photos of the two techniques to fully understand the differences.