(A) Epidermis
(B) Papillary dermis
(C) Reticular dermis
(D) Subcutaneous layer

The correct response is Option D.

The hair follicles are located within the subcutaneous layer of the scalp. Human hair is primarily composed of the keratin protein; the hair shaft is produced by the matrix, which is in turn produced by the follicle. Hair follicles are indentations of the epidermis located within the subcutaneous layer of the scalp. It is important to know the anatomy of the hair follicle in order to successfully harvest and transplant scalp hair, which can be retained with some degree of permanence following transplantation. Because successful punch grafting depends on meticulous technique, the grafts should be harvested at the appropriate depth while avoiding trauma to the hair follicles.

References
1. Uebel CO. Micrografts and minigrafts: a new approach for baldness surgery. Ann Plast Surg. 1991;27:246.
2. Vallis CP. Hair replacement surgery. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:1514-1537.

A 55-year-old man who has had stable hair loss for the past several years wishes to undergo hair transplantation. Conservative management with administration of finasteride has not been successful. On examination, he has Hamilton's class 6 male pattern alopecia that extends from the anterior hairline to the vertex. He has dense, curly hair in the parieto-occipital region of the scalp and excellent scalp vascularity and elasticity.

Which of the following is the most appropriate initial management?

(A) Psychological profile and screening
(B) Trial therapy with minoxidil
(C) Establishing the anterior hairline with punch grafts
(D) Establishing the anterior hairline with scalp flaps
(E) Sagittal scalp reduction

PHOTO

Reproduced with permission of Bell ML. Scalp reduction. Clin Plast Surg. 1982;9:269.

The correct response is Option E.

Scalp reduction is currently the most appropriate management of male pattern alopecia. This technique is simple and associated with few complications. Surgical removal of the hairless scalp will diminish the total area that requires grafting and will assist with conservation of donor sites. Although various excision patterns can be used based on baldness pattern, sagittal excision patterns are preferred because they will remove the greatest amount of bald skin due to the excess of scalp laxity seen in the sagittal plane. The surgeon should perform scalp reduction before surgically re-establishing the anterior hairline.

Minoxidil is an antihypertensive drug that has been shown to increase hair growth when applied to the scalp of men who have thinning hair. However, this drug does not work in patients who have extensive hair loss, such as those
Psychological screening is not routinely performed in patients who request treatment of male pattern alopecia.

References
1. Dardour JC. Treatment of male pattern baldness and postoperative temporal baldness in men. Clin Plast Surg. 1991;18:775-790.
2. Pinski JB. Hair transplantation and bald-scalp reduction. Dermatol Clin. 1991;9:151-168.

Which of the following is most closely associated with male pattern alopecia?

(A) Absence of a genetic predisposition
(B) Decreased activity of 5alpha-reductase within genetically susceptible hair follicles
(C) Increased serum level of testosterone
(D) Prolonged anagen phase
(E) Prolonged telogen phase

The correct response is Option E.

Male pattern alopecia is associated with a prolonged telogen, or quiescent, phase of the hair growth cycle. During this phase, the follicle becomes inactive, and active hair growth ceases.

Inheritance is the only known cause of male pattern alopecia. Although hereditary alopecia is controlled by a single, dominant, X-linked autosomal gene, polygenetic modifying factors, such as androgen production and age, affect its expressivity. Male pattern alopecia can only be triggered by a normal adult male serum androgen level if there is genetic predisposition.

Alopecia results from increased 5alpha-reductase activity within genetically susceptible follicles. It has not been shown to be associated with increased plasma levels of testosterone. The anagen phase of the hair cycle, during which hair actively grows, is typically shortened in patients with alopecia.

References
1. Hamilton JB. Male hormone stimulation is a prerequisite and an incitant in common baldness. Am J Anat. 1942;71:451.
2. Vallis CP. Hair replacement surgery. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:1518-1520.

Which of the following is most closely associated with the anagen phase of the hair growth cycle?

(A) Active hair growth
(B) Destruction of the follicular bulb
(C) Duration of two to three weeks
(D) Keratinization of the base of the hair
(E) Lack of hair growth

The correct response is Option A.

Inheritance is the only known cause of male pattern alopecia. Although hereditary alopecia is controlled by a single, dominant, X-linked autosomal gene, polygenetic modifying factors, such as androgen production and age, affect its expressivity.

The growth cycle of hair follicles is divided into three distinct phases Ð anagen, catagen, and telogen. In the anagen phase, which lasts approximately three years, the hair actively grows through division and keratinization of the follicular cells. Approximately 90% of the scalp hairs are involved in this phase. In the catagen phase, the follicular bulb is destroyed and the base of the hair is keratinized; this phase lasts approximately two to three weeks. Finally, in the telogen phase, the follicle is inactive and active hair growth ceases. Approximately 10% of the scalp hairs are in this phase at one time.

References
1. Hamilton JB. Male hormone stimulation is a prerequisite and an incitant in common baldness. Am J Anat. 1942;71:451.
2. Vallis CP. Hair replacement surgery. In: McCarthy JG, ed. Plastic Surgery. Philadelphia, Pa: WB Saunders Co; 1990;2:1518-1520.