The first point to realize with a brachioplasty that the scar is the biggest issue with the overall outcome. You have to trade the excess skin and fat of the upper arm for a much better and tighter shape to the upper arm, but at the expense of scar.
So there have been many different approaches to addressing the scar in brachioplasty. These range from the traditional inner medial incision to a posterior based incision to short scar types.
The traditional inner medial incision is well hidden when the arms are down at your side, but quite noticeable when your arms are up.
The posterior incision is located at the bottom part of the upper arm when your arms are raised at 90 degrees to your body. This scar is not seen from the front when your arm is by your side. It is also not seen when your arm is raised up. The only time this is seen is from behind when your arm is by your side.
I draw a red line with a marker on my patients arms in both locations so they can decide for themselves which scar they would rather have.
As for the short scar brachioplasty, this tries to hide the scar horizontally in the armpit. It can be useful in people with arm laxity in the upper 1/3 of the upper arm, but it doesn't reduce the circumferential excess that is frequently seen in people needing brachioplasty.