Hamilton-Norwood classification is the most popular and the most widely used classification for male baldness. Dr. O’tar Norwood published this classification in 1975. This classification entails two major patterns and also several less common ones. There are two main areas of hair loss: bitemporal recession and thinning over the crown. Hair loss in these two areas increase as baldness progresses leading to coalescence until front, top and crown are entirely bald.

It does not indicate balding but represents an adolescent or juvenile hairline. It rests on the upper brow crease.

Class II

It indicates progression to adult or mature hairline located at 1.5cm above above the upper brow crease. There is accompanying temporal recession.

Class III

Is the earliest stage of male hair loss. It is characterized by a deepening temporal recession.

Class III Vertex

Vertex represents early hair loss in the crown

Class IV

Is characterized by further frontal hair loss and enlargement of vertex. There is still a solid band of hair across top separating front and vertex.

Class V

The bald areas in the front and crown continue to enlarge and the bridge of hair separating the two areas begins to break down.

Class VI

Occurs when the connecting bridge of hair disappears leaving a single large bald area on the front and top of the scalp. The hair on the sides of the scalp remains relatively high.

Class VII

Patients have extensive hair loss with only a wreath of hair remaining in the back and sides of the scalp.