The crown is located on the back portion of the scalp. Specifically, where the posterior scalp starts to slope downward. The crown ends where the occipital bone begins – the occipital scalp is where donor hair is usually taken from, especially for follicular unit strip surgery (FUSS). The occipital scalp is not part of the crown. The very top of the scalp, right before the posterior scalp begins to slope downward, is sometimes referred to as the vertex transition point, or simply as the vertex (the term “vertex” literally means “the highest point”). Many people confuse the vertex and the crown as being the same thing, but they are not. In the diagram to the right the vertex is also referred to as the mid-scalp.
Unlike MPH, FPH is always delineated by some degree of hair loss in the crown area. Whereas MPH may sometimes start as a receding hairline, FPH often occurs as a thinning spot in the center of the scalp that slowly expands outward to encompass all areas of the scalp.
A whorl is a point on the crown that grows hair in a circular direction, either clockwise or counterclockwise. This shape of the whorl is largely what determines the resting position of a person’s hair, otherwise known as their hair geometry. It is possible to have more than one whorl, which can present additional challenges for reconstructive procedures.
Recreating the hair’s natural spiral is the greatest challenge of reconstructing this particular region. A physician must be careful to angle each follicular unit in such a way that a natural-looking geometric pattern is formed. The direction of the whorl must also seamlessly blend with the direction of the remaining hairs on the midscalp, if any. Finally, the spiral itself must be tight – a whorl that is not dense enough will be extremely noticeable to others.