In the past two years I have made a small but significant modification to my hair transplant work that I would like to share with my prospective and established patients. The concept is convergence and how to place grafts especially toward the midline of the head in such a way as to achieve even greater degree of density per transplanted graft.

Principle of Convergence Illustrated

Let’s take a step back and explain two concepts that are needed to understand how convergence works. First, the central forelock describes the anatomic region found immediately behind the hairline zone in the midline. It is the most important area to transplant in terms of creating visual hair density to make an individual look less bald. In fact, I tend to use stronger 3 to 4 hair grafts in this region as opposed to 2-hair grafts elsewhere and even select the thickest 3 to 4 hair grafts for placement here for added visual punch. In addition, I place grafts into the central forelock with added density aiming upwards of 50 to 55 grafts per square centimeter as compared with as low as 20 to 25 grafts per square centimeter in areas of less visual importance like the posterior midscalp.

The second concept to introduce before directly speaking of convergence is the effect that the shape of the head has on the transplanted grafts. Since the shape of the head is round, grafts that are placed perpendicularly upward will have a tendency to splay open and fall outward toward the sides of the scalp like an open book. Because the central forelock, described above, is situated in the center and is aesthetically the most important area for transplantation, if grafts fall away from the center that is a problem regarding visual density. Accordingly, the technique of convergence rectifies this splaying and helps to concentrate graft density toward the midline.

The way that convergence works is by having the grafts slightly tilt inward toward the center and slightly also point in a directed fashion about 20 to 30 degrees toward the midline. This direction helps the hairs naturally augment the center for visual density but also helps to counteract the natural splaying effect that occurs by virtue of the head shape.

Samuel M. Lam, MD, FACS, a board certified hair transplant surgeon in Dallas, Texas. If you would like to schedule a consultation please call 972-312-8105, or visit for more info.