The correct response is Option B.

Male-pattern alopecia is characterized by a decrease in the anagen, or active, phase of the hair follicle and an increase in the telogen, or resting, phase. Patients with this condition have more of their hair follicles in the resting phase, and those in the active phase produce hair growth for a shorter time. Hair follicles can also be classified as either terminal, which produce larger, pigmented fibers, or villous, which produce finer fibers that have less pigmentation and are more difficult to visualize. Terminal fibers are found typically on the adult scalp, eyebrows, axilla, and pubic region, while villous fibers are noted on the forehead, bald scalp, and along the hairline itself. In patients with male-pattern alopecia, many follicles in the scalp are transformed from terminal to villous.

Minoxidil is the recommended treatment of male-pattern alopecia. This agent halts the hair loss and increases the number of hairs as well as the diameter of the existing hairs, but is only effective in patients with mild to moderate baldness.

References
1. Orentreich N, Durr NP. Biology of scalp hair growth. Clin Plast Surg. 1982;9:197.
2. Rushton DH. Management of hair loss in women. Dermatol Clin. 1993;11:47.

According to the donor dominance concept of hair transplantation, which of the following is the most appropriate donor site?

(A) Frontal scalp
(B) Occipital scalp
(C) Parietal scalp
(D) Sideburn
(E) Vertex

The correct response is Option B.

In order to successfully transplant hair using minigrafting or micrografting techniques, the surgeon must understand the concept of donor dominance, which states that each hair follicle possesses its own individual, genetically-defined lifespan. Because of this, hair follicles located in those areas that tend to have a longer lifespan will continue to possess the same lifespan even after they have been transplanted. The hairs of the occipital scalp have the longest genetically-defined lifespan in most patients; in addition, this donor site is acceptable aesthetically.

Depending on the classification of male-pattern alopecia, early hair loss can occur in the frontal, parietal, or vertex regions. The sideburns often have a lifespan that is genetically similar to the occipital area, but the donor site is quite small and usually unacceptable.

References
1. Barrera A. Micrograft and minigraft megasession hair transplantation results after a single session. Plast Reconstr Surg. 1997;100:1524-1530.
2. Bell ML. Scalp reduction. Clin Plast Surg. 1982;9:269-278.