The inframammary incision (#2) is placed where we anticipate the lower breast skin fold will be after the implant is placed.  Usually, the breast implant has a larger diameter than the diameter of the pre-operative breast base.  In order to place the center of the breast implant directly behind the nipple, the implant pocket must be disected lower than the pre-operative inframammary fold.  We therefore, typically place the inframammary incision 1-2 cm lower than the pre-operative inframammary fold, anticipating that this is where the post-operative inframammary fold will be after the implant has been placed.  

The inframammary incision allows best visualization for the surgeon and is the easiest incision to use for procedures conducted under local anesthesia.  It works equally well for subglandular or submuscular implant placement.  The scar is nicely camouflaged by the shadow at the inframammary fold. 

 

Illustration from Aesthetic Plastic Surgery, Second Edition by Thomas D. Rees, MD, and Gregory S. LaTrenta, MD.  Published by W.B. Saunders Company.  Used by permission.