How Breast Implants Work

breast implant
There are many breast implant options now. Webphotographeer / Getty Images

In 2003, plastic surgeons performed 280,401 breast-augmentation surgeries in the United States. This made breast augmentation the second most common elective surgery and the most common type of breast surgery for that year. Breast augmentation, or augmentation mammoplasty, is the insertion of breast implants into a woman's breasts to increase their size. These implants have been the center of controversy for almost 30 years.

In this article, HowStuffWorks looks at breast implants and the surgery that inserts them into a woman's breasts. We'll examine the history and controversy surrounding breast implants and the risks associated with them, describe the various methods used to implant them, and learn how men also use breast surgeries to alter their appearance.


Anatomy of a Breast

In order to understand how breast implants work, it helps to understand the structure of the breast. Breasts are tear-shaped, milk-producing glands that cover a woman's pectoral muscles and are suspended over the rib cage. They are held in place by supporting ligaments and muscles.

The structure of the breast is divided into two functional components: the epithelial component (the system that produces milk) and the structural component (the system of fatty tissue and ligaments that support and protect the structure of the breast).


The epithelial component is comprised of a series of 15 to 25 lobes arranged in an orderly fashion around the center of the breast (imagine the petals of a flower). Each lobe contains clusters of lobules that resemble clusters of grapes. All of the lobules end in dozens of tiny milk producing bulbs. The lobes all connect to a network of ducts called the lactiferous sinus, which carries milk to the nipple. The nipple is surrounded by the areola -- the dark, circular tissue that crowns the outside of the breast. The lactiferous sinus carries the milk through the nipple and out of the breast.

The structural component of the breast is comprised mostly of a fatty tissue called adipose. There is no muscle in the actual breast, but there are a series of muscles behind and underneath the breasts. These muscles work in conjunction with a ligament called Cooper's ligament, and together they act like a natural bra, supporting the weight of the breasts on the front of a woman's body.

The size and shape of a woman's breasts are primarily determined by hereditary. Other factors that can affect breast size (outside of traumas and cancer) include fluctuating weight, medications, pregnancy, menstruation, and menopause.

Click the play button to see inside of a breast.

If the above animation is not working, click here to download the Quicktime player.

In the next sections, we will examine how plastic surgeons use specialized tools and techniques to increase the size of breasts.

Breast Implant Basics

This photo demonstrates the difference between high profile and standard saline implants.
This photo demonstrates the difference between high profile and standard saline implants.
Photo courtesy

Breast implants are small, medical-grade sacs comprised of an elastomer shell with a self-sealing filling valve located on either the front or back. Breast implants are filled with silicone gel or a sterile saline solution (salt water).

Some implants are pre-filled, but most are filled after surgery. It's this filling that blows the implant up like a water balloon to increase breast size. Saline implants are the most common type of implant used today due to the FDA's ban on the use of silicone breast implants in the United States in 1992 (although silicone implants are still available in certain circumstances -- see the Controversy section).


Breast implants come in a variety of shapes and sizes. The size of breast implants is measured in cubic centimeters (ccs), and they increase the size of a woman's breasts one cup size every 175 to 200 ccs.

Breast implants come in a variety of sizes.
Breast implants come in a variety of sizes.
Photo courtesy

Generally, implants come in three sizes, and the size of the implant that is used depends on the patient's desired outcome and the size breasts that their physical frame can support. Choosing a breast implant that is too large can cause surgical complications or make the implant visible through the skin after the surgery.

In the next section, we'll look at some of the special features of breast implants.

Implant Shape

To meet the needs of different patients, breast implants come in different shapes.
To meet the needs of different patients, breast implants come in different shapes.
Photo courtesy Inamed Aesthetics

Size is not the only issue to consider when discussing implants. To get the safest and most natural-looking results, breast implants are made with a variety of features in mind. The first of these features is shape. Breast implants come in two shapes: round and contoured.

Round implants are the most common type of implant used. Many women choose round implants because they tend to provide the greatest amount of lift, fullness and cleavage. Some women, however, find the round implants too fake looking and opt for more natural-looking alternatives.


Contoured implants have a more tear-drop shape to mimic the anatomical shape of the breasts. Contoured implants were originally developed for breast reconstruction but have become quite popular in augmentation surgery for women who want a more natural shape. The best shape for the job is usually worked out between the surgeon and patient, and the variables they consider are:

  • The amount of tissue the surgeon has to work with
  • The patient's anatomy
  • Where the surgeon places the implant in the breast

The thing to bear in mind is that the placement of the implant has a far greater effect on the final look of the augmentation than the shape of the implant.

Implant Texture

A capsule of scar tissue forms around the implant after surgery. This is a natural reaction of the body to protect itself from the introduction of a foreign object. The formation of this scar capsule is called capsular contracture. In extreme cases, this scar capsule will result in a hardening of the breasts, which may be painful and requires additional surgery.

Textured breast implants were created to reduce the chance of capsular contracture. The textured surface of these implants allows the scar tissue to adhere to the implant, hopefully decreasing the amount of scar tissue that grows. In addition, the implant sticking to the scar capsule prevents it from moving around inside the breast. It is still debatable whether or not textured implants actually reduce the instances of capsular contracture; but evidence does indicate that textured implants have a greater tendency to rupture.


Smooth breast implants move around freely inside of the capsule. This freedom can create a more natural movement in the overall breast; however, depending on the placement of the implant, it can sometimes create an undesirable side effect known as rippling (see the Risks section). There are many variables that affect rippling, and the surgeon will guide the patient toward the implant texture for her anatomy.


A less commonly used type of implant is the Spectrum Expandable saline implant. This implant has a three-part system consisting of the Becker valve, fill tube, and reservoir system. An expandable implant can have saline added or removed in 50 cc increments using a fill port that is surgically implanted into the patient's armpit, allowing for minimally invasive post-operative adjustment.

The fill port is attached to a tube that directs saline to and from the implant reservoir. Once the patient is happy with the size and final look of the implants, a minor procedure removes the fill port and tube. A three-part seal made up of a kink valve, leaf valve, and the plug on the implant closes the valve without a need for additional surgery. Unlike normal implants, once the valve on an expandable implant is closed, it cannot be reopened; this creates the disadvantage that if it needs to be removed in a revision surgery, it must be removed without being drained, which requires a much larger incision.


In the next section, we'll discuss the importance and ramifications of implant placement.

Implant Placement

One of the most important factors in a successful breast augmentation is the proper placement of the implant. There are three places implants can be put to increase the size of a woman's breasts:

  • Subglandular
  • Subpectoral
  • Submuscular

Subglandular placement puts the implant directly behind the mammary gland and in front of the muscle. This placement requires the least complicated surgery and yields the quickest recovery. Athletic women may opt for this placement because it prevents flexing chest muscles from interfering with the look or integrity of the implant.


The downsides of this placement are increased chance for capsular contracture, greater visibility and vulnerability for the implant. This is because only the flesh and gland separate the implant from the outside world. Depending on the amount of available breast tissue, the implant may be seen "rippling" through the skin.

Subpectoral placement involves lodging the implant under the pectoralis major muscle. Because of the structure of this muscle, the implant is only partially covered. This alternative reduces the risk of capsular contracture and visible implant rippling, but recovery time from this positioning is typically longer and more painful because the doctor has to manipulate the muscle during surgery. Also, because of increased swelling, the implant may take longer to drop into a natural position after surgery.

If the augmentation is being performed to lift sagging breasts, this type of placement may not be the right approach. Because the implant is only partially covered by the muscle, the weight of the fluid is not supported. In a woman with sagging breasts, the implant may droop and create two separate bulges in the breast lobe.

Submuscular placement puts the implant firmly behind the chest muscle wall. The implant is placed behind the pectoralis major muscle and behind all of the supporting fascia (connective tissue) and non-pectoral muscle groups. Submuscular implants tend to be the best for mammograms, as they put the implant fully behind the area that needs to be examined. This placement has the same drawbacks of subpectoral placement with an even longer recovery time.

In the next section, we will learn about the different procedures surgeons use to put the implants in place.


Sizers are used to test implant placement and size during augmentation surgery.
Sizers are used to test implant placement and size during augmentation surgery.

Depending on the patient and the desired outcome, breast augmentation surgery can be a very simple or very complex procedure.

After pre-operative preparation, the surgery starts by cutting one incision into the patient for each implant. The incisions are small and placed so that the scarring is minimal and hard to see. Once the incision is created, the surgeon must cut a path through the tissue to the final destination of the implant. Once that path has been created, the tissue and/or muscle (depending on placement) must be separated to create a pocket for the implant. This is where the surgeon's skill really comes into play: When deciding where to cut the pocket in the breast, the surgeon must predict what the breasts will look like once the implants are filled. In more extreme augmentation surgeries, this involves repositioning the nipple, adjusting for cleavage and creating a new crease under the breast.


In some cases, augmentation surgery is accompanied by mastopexy (breast lift) surgery so that everything ends up in the right place. To aid in positioning, the surgeon may decide to use a sizer or disposable implant. Sizers are temporary implants attached to a tube that the surgeon can work inside the pocket and fill up to test placement, implant size and fill levels. Once this has been tested, the sizer is removed and replaced with the permanent implant.

When inflatable implants are used, they are rolled up like a cigar and pushed into the incision, through the channel and into place. This is true no matter which type of incision is used (we'll talk about incisions in the following sections). Once the implant is positioned, the incision is closed. In the last step, the surgeon uses a syringe to fill the implant with saline through the valve, filling it to the predetermined size.

If the patient has opted to use pre-filled implants, the incision will be larger. Inserting textured, pre-filled implants requires the longest incision, providing more room for inserting an implant with a rough shell and for manipulating the less-pliable implant once it's in place.

Plastic surgeons can use one of four different types of incisions to insert the implant into the breast: peri-areolar, inframammary fold, transaxillary, and TUBA. In the next sections, we will learn the difference between these types of incision.

Peri-areolar Incision

The peri-areolar incision, or nipple incision, is one of the most commonly used incisions in breast augmentation surgery. The nipple incision allows sub-glandular, sub-pectoral, or sub-muscular placement of the implant. The implant can be both inserted and removed through the nipple incision in the event of complications.

The incision is made where the darker skin of the areola meets the lighter skin of the breast. This allows the scar to blend in with the natural change in flesh pigment. The implant is rolled up into a protective sleeve before being inserted. The sleeve prevents the implant from coming into contact with bacteria in the lactiferous sinus, which could cause germ contamination after the surgery. After placement, the sleeve is removed.


One of the greatest advantages of this type of incision is that the surgeon works close to the breast, allowing for very precise placement of the implant.

Click the play button to see one type of incision used during a breast lift.

If the above animation isn't working, click here to download the Quicktime player.

Inframammary Fold Incision

The inframammary fold incision is another very common incision used for breast augmentation. Like the nipple incision, this incision allows for all three placement types and both insertion and removal of the implant.

The incision is made in the crease under the breast, allowing for discreet scarring. Once the incision is made, the implant is inserted and worked vertically into place. This bypasses the milk ducts, so the protective sleeve is not necessary.


When increasing breast size considerably, the surgeon often has to create a new crease in order to center the nipple on the new, larger breast and to accommodate the large implant. This presents one of the only disadvantages of this type of incision: A certain amount of guesswork goes into crease placement. However, misplacing the crease is a very rare complication and can usually be dealt with in a revision surgery.

Transaxillary Incision

Patients who want no breast scarring at all often opt for the more difficult transaxillary incision. This incision is made in the armpit and leaves a tiny scar that is virtually impossible to see.

The transaxillary procedure can be preformed with or without the help of an endoscope (a tube with a small surgical camera on the end). The cut is made in the fold of the armpit and a channel is cut to the breast. The implant is inserted into the channel and worked into place.


Transaxillary incision presents a greater challenge for surgeons because working that far away from the breast makes placement more difficult.

Like nipple and crease incisions, the armpit incision can be used for implant placement anywhere in the breast. The biggest draw back of the transaxillary incision is that if a complication occurs that requires revision or removal, then chances are the surgeon will have to make a nipple or crease incision to work on the implant. It is very rare that surgeons can reuse the transaxillary incision -- it's very difficult to work on an implant that far away from the breast.

TUBA Incision

The TUBA (trans-umbilical breast augmentation) incision, or the bellybutton incision, is much less common than the other three. This incision is made in the rim of the bellybutton. Then, using an endoscope, a tunnel is cut through the subcutaneous fat just below the skin all the way to behind the breast. As in all techniques, a pocket is then cut for the implant. The implant is rolled up and pushed through the tunnel into place.

In this technique, the implant is filled before the incision is closed using a fill tube that is snaked through that tunnel. The surgeon uses the endoscope to make sure everything is in place and then closes the incision.


While this may seem extreme, this is actually one of the least invasive techniques. The skin on the abdomen has greater elasticity than other types of skin and can take the tunneling. Very rarely, this procedure leaves "V" tracks on the stomach. Overall, the scarring and recovery time is far less with a TUBA incision than with the other three.

There are limitations with the TUBA incision:

  • The procedure requires inflatable implants.
  • TUBA can only be used for sub-pectoral or sub-muscular placement.
  • In the event of complication or revision, the TUBA incision (like the armpit incision) cannot be reused -- the surgeon will have to make a nipple or crease incision to work on the implant.
  • Few plastic surgeons are willing or able to perform it -- this procedure makes for the greatest room for error when placing the implant due to the distance from the breast.

In the next section, we will look at some of the risks associated with breast augmentation surgery.


As with all surgeries, there are risk associated with breast augmentation. First and foremost, there is the risk of infection. Unusually high fevers are generally an indication of infection after surgery, and patients should watch for this after any invasive medical procedure.

Let's go over some of the risks specific to implant surgery.


Bottoming Out

This is the effect created when the implant sits too low and the nipple rides to high. This creates an unnatural look that is the result of cutting too large a pocket for the implant. It can also be caused by the weight of the implant in thin-skinned women. This is correctable with additional surgery.

Capsule Contracture

Capsular contracture is not a risk or complication in the traditional sense: It is definitely going to happen to a certain degree. It's the amount of contracture that is the issue. Capsule contracture causes the implant to be squeezed by the fibrous scar tissue that forms around it. The result can be a painful hardening of the breasts. This is the most common complication of breast-augmentation surgery. It is dealt with in a revision surgery where the scar tissue is scraped out to make more room for the implant. It can sometimes take several of these surgeries to correct the problem.


This is a common surgical risk that is caused by blood pooling under the skin. It can create discolored, possibly painful lumps. This can be corrected with surgery or drainage.

Interference with Mammography

The saline or silicone in breast implants can obscure X-ray results and hide potentially cancerous growths. Submuscular is the best placement to reduce this risk. It is important that the radiologist knows the patient has implants when performing a mammography, as there are techniques that can be used to help work around them.


Necrosis or "tissue death" is a rare and serious complication. Dead tissue can form around the implant and prevent healing. This has to be dealt with by surgery or complete removal of the implant. Necrosis usually leaves large, permanent scars.


While women with breast implants can participate in a variety of activities without fear, they must be mindful that their implants are not indestructible. Most breast implants come with a lifetime manufacturer's warranty that covers operational failure. But many things that cause implants to rupture are not covered by warranty, and some things (like certain surgeries and over- or under-filling) will actually void the warranty.


Seroma is a collection of fluid around the implant. This minor problem is handled by draining the fluid with a needle.


Symmastia is one of the rarest risks -- it is the result of a surgical mistake that causes the implants to lift off the sternum. The result is one large breast across the front of the body, with no cleavage. This complication is hard to repair.

Traction Rippling

This occurs when a textured implant settles into place after the swelling has gone down. As the implant drops, it pulls on the scar tissue, which pulls on the skin. The result is a rippling in the breast. Only the use of smooth implants eliminates this risk.

Breast augmentation is one of the most common types of plastic surgery today. As with all surgeries (especially elective ones), it is important to understand the risks involved. For the most current and detailed information on all of the risks associated with breast augmentation, consult a qualified physician.

In the next section, we'll learn how men use plastic surgery to enhance their chests.

Not Just for Women

While men don't have breasts to enlarge, there is a procedure that uses implants to increase chest size. Pectoral implants come in different contoured sizes that naturally curve to the shape of male pectoral muscles. Pectoral implants can create a larger, more defined chest on a man.

Pectoral implant surgery is done with an armpit incision. Using an endoscope, the doctor guides the implant through the patient's body and lodges it behind the pectoral muscles. The procedure is nearly identical to transaxillary breast implant surgery for women.


On the other end of the spectrum is male breast reduction, for gynecomastia. Age, diet or heredity can result in fatty deposits or gland formation over the pectoral muscles that resemble breasts. Plastic surgeons can remove this abnormality by cutting small, elliptical incisions under the nipple and performing a type of liposuction. Using a suction rod called a cannula, the excess fat is vacuumed from the area.

If glands are the reason for growth, the surgeon simply removes them and stitches the incision. The procedure usually has to be preformed more than once to completely eliminate the extra tissue.

In the next section, we'll examine the some of the controversies surrounding breast implants.


Breast implants first appeared in clinical circles in 1960. Two years later, Timmie Jean Lindsey became the first woman to undergo breast augmentation surgery using silicone breast implants.

The 30 years following Timmie Jean Lindsey's successful breast augmentation saw endless courtroom battles over the safety of silicone breast implants. When a silicone implant ruptures, medical-grade silicone is absorbed into a woman's system. The effects of this absorption are unclear.


Industry officials, consumer-advocate groups and interested third parties have tapped experts in all applicable medical fields to study the side effects of silicone breast implants. None of these studies could produce compelling evidence that either confirmed or denied a connection between silicone implants and illness. A congressional hearing held on the matter failed to turn up any conclusive results.

In 1992, FDA Commissioner David Kessler asked implant manufacturers to affect a voluntary moratorium on the sales and distribution of silicone breast implants in the United States. Since then, silicone breast implants have been available in the United States only in special circumstances:

  • If they are part of a breast reconstruction due to mastectomy (a medical procedure to remove part or all of a woman's breast to prevent the spread of breast cancer)
  • If they are meant to replace saline implants in a revision surgery due to complication
  • If the patient has agreed to be part of clinical trials for five to 10 years after surgery

FDA-approved saline implants are made the same way as their silicone predecessors but are instead filled with a sterile mixture of salt and water. However, the switch to saline was hardly a perfect solution: Women with saline implants have complained that they produce an unnatural look and feel, and some women have had saline implants removed due to dissatisfaction or complications. To this day, the debate rages on the pros and cons of saline versus silicone.

To read the results of some of the independent studies done on the side effects of silicone breast implants, check out the links below:

For more information on implants, augmentation and other breast surgeries, check out the links on the next page.