Why are surgical incisions parallel to cleavage line?

Question

Why are surgical incisions parallel to cleavage line?

Answer 1

They aren't always.  It depends on the surgery.  Where the surgeon makes the incision depends on what s/he needs to expose.  Some incisions go side to side, such as the Pfannenstiel incision (done for C-sections and hysterectomies) or McBurney's incision (done for open appendectomies).