Breast Implant Anatomy

Reviewed by Walter Erhardt, MD

If you are considering breast augmentation with implants, you may have some questions about breast implants and their various components. You have come to the right place. Here you will find important information on breast implant anatomy and your implant options.

In general, breast implants consist of:

  • the shell (the outside layer, sometimes called the envelope or lumen)
  • the filler (inserted into the shell)
  • the patch (covers the hole where the filler is inserted into the shell)

Silicone Shells for Both Saline and Silicone Implants

Both silicone and saline breast implants have an outer shell made of silicone, but when someone refers to a "silicone breast implant," they mean the filler of the implant, not the shell. Typically, the shell is made of a single layer ("single lumen"), but some implants have a double layer — a shell within a shell ("double lumen").

The two types of implants used in the United States are:

  • saline-filled, silicone-rubber shell
  • silicone gel-filled, silicone-rubber shell

Saline-Filled Breast Implants

Saline implants are filled with a sterile saline (saltwater) solution.

There are several types of saline-filled breast implants. Common saline implant types include:

  • Single lumen, prefilled to a fixed volume, with no valves for filling during surgery or for adjusting after surgery.
  • Single lumen, filled with a fixed volume of saline during surgery through a valve, with no adjustments to the implant volume.
  • Single lumen, filled during surgery, with a valve for the purpose of adjusting the volume of saline following surgery.

Silicone Gel-Filled Breast Implants

Silicone breast implants were introduced to the market in 1962, but the Food and Drug Administration (FDA) stopped sales of these implants in 1992 due to safety concerns. After a thorough investigation, the FDA re-approved silicone-gel filled implants in 2006.

These implants are now approved for women of all ages who need breast reconstruction and for women age 22 and older for breast augmentation. The reasoning behind the age restriction is that a woman's breast tissue is still developing into her 20s, and the FDA believes that women aged 22 and older are more able to make informed, educated decisions than their younger counterparts.

Five years after the re-approval, the FDA stated that silicone gel-filled breast implants are relatively safe, but many women will require implant removal within 10 years due to implant rupture or a local complication such as implant hardening. The FDA will continue tracking safety information on these breast implants.

The filler in silicone gel-filled breast implants is composed mainly of silicone gel. Silicone has been widely used in a number of medical applications for many decades.

There are several types of silicone-filled breast implants:

  • Single lumen, prefilled by the manufacturer to a specific volume.
  • Double lumen, with the inner lumen prefilled by the manufacturer to a specific volume and the outer lumen filled during the breast augmentation procedure with a fixed volume of silicone gel using a valve in the implant.
  • Double lumen, with the outer lumen prefilled by the manufacturer with a fixed volume of silicone gel and the inner lumen filled during the procedure through a valve in the implant. This third type allows for adjustments to the filler volume after surgery.
  • Highly cohesive silicone gel implants, which contain a gel that is more viscous than the gel used in the other implants — similar to the consistency of a gummy bear candy. If these gummy bear breast implants rupture, the gel will not migrate due to its consistency. These implants are not yet approved by the FDA.
Learn more about breast implants

Fat grafting to the breast is another option for breast augmentation. This procedure involves removing fat from areas of the body where it is plentiful and injecting it into the breasts. It can be used with breast implants to correct certain complications such as rippling and wrinkling.

After you have educated yourself on breast augmentation with implants, schedule a consultation with a board-certified plastic surgeon to help determine which implant is right for you. Start your search for the right surgeon here.

[page updated June 29, 2011]