With the Brazilian buttock augmentation, fat is harvested and then processed and injected in the buttock to recreate a nice shape but at the same time some projection. When the fat is injected is very technique dependent and there are 2 different levels were fat is injected for the best result. If you look at the anatomy of the buttock, there is large muscle called the gluteal muscle. This is the muscle that provides the bulk of the muscle mass to this area. On top of the muscle, there is a fascia that many times is very thick and then on top of that we have the superficial fascia which is a layer of fibrous tissue plus fat. When fat is injected, we need to do it in both layers, the intramuscular inside the muscle and also outside the muscle. Because the muscle has a very good blood supply, it is generally accepted that the fat that is injected inside the muscle tends to last longer and the chances of losing fat after the procedure are less because the blood supply will allow the fat to survive for very long period of time. The blood supply on top of the muscle is not as great but nevertheless most of the projection that you will get after the surgery is by injecting the fat above the muscle, when we inject fat inside the muscle you will get some projection but not a lot, the limiting factors whenever we inject fat inside the muscle is the fascia that surrounds the muscle, this fascia is not very elastic, so when we inject fat inside the muscle the fascia will expand but many times it will not result in the desire projection. Injecting fat over the muscle is necessary for projection and shape. If we want to change your shape into on hourglass shape, then injecting the fat inside the muscle is not going to result in that shape that you desire. Because the muscle is mainly located on the central part and extended inferiorly to attach to the leg, so changing your shape from a square, round or any other shapes requires the fat to be injected in the superficial fascia or the layer that is above the muscle. There are many things that we have to take into consideration when injecting fat, for example, the more fat is injected inside the muscle, the highest the risks of having significant complications like a fat embolism, compression of the nerve of the leg, etc. These are the complications that are part of the consent process of this procedure and there are things that you need to consider before the surgery, essentially I typically inject 40% of the fat inside the muscle and 60% of the fat outside the muscle. I have found over the years that this gives me a very consistent result and I am able to change the buttock shape significantly minimizing complications and at the same time consistent nice results.