Hamilton’s Norwood Classification for Males.
The Norwood classification, published in 1975 by Dr. O'tar Norwood, is the most widely used classification for hair loss in men. It defines two major patterns and several less common types (see the chart below). In the regular Norwood pattern, two areas of hair loss–a bitemporal recession and thinning crown–gradually enlarge and coalesce until the entire front, top and crown (vertex) of the scalp are bald.
- Class I
Rrepresents an adolescent or juvenile hairline and is not actually balding. The adolescent hairline generally rests on the upper brow crease.
- Class II
Indicates a progression to the adult or mature hairline that sits a finger’s breath (1.5cm) above the upper brow crease, with some temporal recession. This also does not represent balding.
- Class III
Is the earliest stage of male hair loss. It is characterized by a deepening temporal recession.
- Class III
Vertex represents early hair loss in the crown (vertex).
- Class IV
Is characterized by further frontal hair loss and enlargement of vertex, but 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.