Breast Implants: Over Or Under The Muscle?

There is often much confusion about what the proper placement of breast implants should be in relation to the breast and the pectoralis major muscle – “the muscle”.

The truth is that the proper placement differs from one patient to another.

The main determinant for proper decision making has to do with whether the breasts are saggy or ptotic. If they are saggy then the next critical question is how saggy they are, and can they be lifted and corrected by breast implants only.

In my practice I do everything to avoid doing a mastopexy because of the scars and especially in young patients. Scars heal more prominently on younger patients versus older individuals.

When the degree of ptosis is mild then it is better to place the breast implants over the muscle and under the breast tissue. This is called a subglandular breast augmentation. Why? Because placement over the muscle accomplishes a greater degree of lift of the breast and a more beautiful result.

What Is a Double-Bubble Deformity?

In the case of a patient with saggy breasts, the breasts are not centered over the pectoralis major muscle and descend below the infra-mammary fold. This means that part of the breast tissue sits lower than the muscle.

If a breast implant is placed under the muscle in this type of patient, then the prominence of the breast implant will be higher than the prominence of the breast. This creates a condition that is called “double-bubble” in plastic surgery. One bubble is the breast implant under the muscle, and the other bubble is the breast prominence below the fullness of the breast implant.

The correction of a patient with double-bubble condition is to either do a mastopexy or breast lift, if the breast implants are kept under the muscle, or to remove the breast implants and place them over the muscle.

When the degree of breast ptosis is moderate to significant then a breast lift or mastopexy cannot be avoided.

I find many women do not want extensive scars on their breasts and if they have a mild degree of breast ptosis, they can be good candidates to have a breast augmentation over the muscle through a very small 4 cm scar.

If a patient does not have any breast ptosis or sagginess then either placement of the breast implants over or under the muscle can offer great results.

Dual Plane Breast Augmentation

The concept of “dual plane” breast augmentation relates to the above principles and is often confusing. What are these two planes? One is the plane under the pectoralis major muscle. The other plane is the plane over the pectoralis major muscle. Most plastic surgeons perform a dual plane breast augmentation to various degrees. The determining degree is once again the degree of ptosis of the breasts, or breast sagginess. If there is no sagginess then there is no need for a dual plane operation. If there is sagginess then the dual plane breast augmentation accomplishes the separation of the breast tissue from the muscle so that it can be lifted more.

However, in cases that lift is needed I feel, in my hands, that a subglandular breast augmentation accomplishes the goals of the breast augmentation and the breast lift without traumatizing the muscles and with much faster recovery.

In certain patients it is excessive to perform a dual-plane breast augmentation to patients who will achieve great outcomes from a subglandular breast augmentation only. The better candidate for a dual-plane breast augmentation is a patient who has very thin breast tissue and mild to moderate breast ptosis.

Patients are not often aware that a dual-plane breast augmentation or a breast augmentation under the pectoralis major muscle weakens the muscle significantly and for life. Also, patients do not realize that when the muscle is divided to allow for breast implant placement, it retracts superiorly. That means the retracted muscle no longer covers the breast implant completely. It only covers the superior part of the breast implant. The middle part of the breast implant and for sure the inferior part of the breast implant is not covered by muscle. This condition sometimes is referred to as “over and under”. This means that the inferior half of the breast implants are not covered by the pectoralis major muscle (over), and the superior part of the breast implants are covered by the muscle (under).

In summary, the proper selection of the breast pocket is different from one patient to another and is based mainly on the relationship between the breasts and pectoralis major muscles. Additional factors such as breast tissue thickness, breast skin elasticity, chest wall and rib anatomy, cleavage distance also play a role in the decision making process.