1. In the fold under the breast (inframammary)
2. Around the areola (periareolar)
3. Through the areola and around the nipple (transareolar)
4. Through the armpit (trans-axillary)
5. Via the belly button (trans-umbilical)
Inframammary fold (IMF) incisions preserve the function of the function of the breast, namely breastfeeding and pleasure. I use this incision most commonly for breast augmentation surgery.
When an incision is made in the fold under the breast, the scar lies in a natural crease and does not tend to stretch or be raised, as can happen in other areas. All structures leading to the nipple and areola (milk ducts, nerves, blood vessels) remain intact. In addition, once an implant is inserted, it is probable during a woman's lifetime that another surgery may be required (to change the implant, remove it later in life, perform a breast lift with drooping, etc.). Therefore, the scar is already present and this can be used again as an incision in the future.
Many other incisions used for breast augmentation are only a one-time option, with the IMF incision required in the future. The IMF scar is hidden in bras and even triangle-top string bikinis, and will only be visible up close when the breasts are lifted.
Peri-areolar incisions are usually around the bottom of the areola, the pigmented circle that surrounds the nipple. There are bacteria that live in this area, and vital milk ducts and nerves in this region. By definition, some of these structures will be divided (cut) during surgery, resulting in a higher risk of complications (infection, numbness, inability to breast feed, etc.). In addition, if a woman makes raised scars, they may be visible beneath a tight shirt or through a bathing suit.
Trans-areolar incisions also cut through breast tissue and/or ducts, blood vessels or nerves. Nipple retraction can also result from scar tissue that normally forms after surgery. For these reasons, I would not recommend this for most women.
Trans-axillary breast augmentation makes an incision in the armpit, or axillary area. This is often a one-time incision, that creates a scar in the area where most women shave, and is also a site of normal bacterial growth (hence deodorant use!). The incidence of infection can potentially be higher, and this incision cannot be reused in the future for addition other surgery.
Trans-umbilical breast augmentation (TUBA) is more of a gimmick than routine approach. A long tube and scope with a camera must be tunneled beneath the skin of the belly button all the way to the area under the breast. If there are any complications during surgery such as bleeding, or if the surgeon cannot adequately visualize what they are doing, a second incision must be made in the IMF. Only a tightly rolled up saline-filled breast implant can be used (not silicone implants), it is also a one-time incision, and a long band of scar tissue beneath the skin is possibly visible after surgery - a permanent deformity. I would never recommend this option to any of my patients.