Whenever possible, I like to go below the muscle. There are a lot of advantages to placing the implant below the muscle as opposed to on top of it. First of all, it's going to give the most natural appearance as you have more tissue covering the implant. So, it's going to feel and look more natural.
Secondly, you're going to have more cleavage as you're going to more fullness is tented and supported up over the implant. It also significantly decreases the rate of scar tissue formation, which is one of the most common side effects or complications associated with implant surgery. Your body normally forms a scar around the implant, and that's called a capsule.
In a small percentage of people, that capsule can actually shrink down and cause the implant to feel hard or move, but going underneath the muscle greatly reduces that risk.
Finally, it actually makes mammograms easier as it gives a separate layer of tissue in between the implant and your breast tissue.
*Individual results are not guaranteed and may vary from person to person.