TABLE 1.

Norwood‐Hamilton Scale.

Type	Clinical definition
I	Minimal recession of the hairline along the anterior border in the frontotemporal (FT) region The anterior border of the hair in the FT region has triangular areas of recession that tend to be symmetrical
II	These areas extend no further posterior than approximately 2 cm anterior to a line drawn in a coronal plane between the external auditory meatus on both sides. Hari is either lost or sparse along the mid‐frontal border of the scape
III	Characterized by deep FT hair recession, usually symmetrical and either bald or sparsely covered with hair. These areas of hair recession extend further posterior than a point that lies approximately 2 cm anterior to a line drawn in a coronal plane between the external auditory meatus on either side
IV	The frontal and FT recession is more severe than type III. There is also sparseness or absence of hair in the vertex area. These bald areas are extensive, but separated from each other by a band of moderately dense hair that joins the fully haired fringe on each side of the head
V	The hair loss over the vertex and FT areas is larger than in type IV and the band of hair between them is narrower and sparser
VI	The hair loss over the FT and vertex regions is confluent and the bridge of hair that crosses the crown is absent
VII	There is only a narrow horseshoe‐shaped band of hair that begins laterally just anterior to the ear and extends posteriorly on the sides and fairly low on the occipital area