English: This picture shows two major patterns of the Dr. O’Tar Norwood's complicated male pattern baldness classification system. This system is based on the Hamilton scale and is often called the Norwood-Hamilton scale.

I: Small to no recession of the hairline.

II: Triangular, often symmetrical, areas of recession at the frontotemporal hairline.

III: Small hair loss enough to be considered as baldness according to Norwood. There are symmetrical deep recession at the temples that are sparsely covered by hair or bald.

III vertex: The hair loss is mostly from the top the head (vertex) with limited recession of the frontotemporal hairline that does not exceed the recession seen in III.

IV: More severe frontotemporal recession than in III and there is sparse hair or no hair on the vertex. The two areas of hair loss are separated by a band of moderately dense hair that extends across the top. This band connects with the fully haired fringe on the sides of the scalp.

V: The vertex hair loss area is separated from the frontotemporal area but it is less distinct. The sparse band of hair across the crown is narrower and the vertex and frontotemporal areas of hair loss are larger.

VI: The bridge of hair that crosses the crown is gone and only sparse hair remains. The frontotemporal and vertex areas are joined together and the extent of hair loss is greater.

VII: The most severe form of hair loss and only a narrow band of hair in a horseshoe shape remains on the sides and back of the scalp. Remaining hair is usually fine and not dense.

Variant A:

IIA: The hairline is anterior to the coronal plane 2 cm anterior to the external auditory meatus.

IIIA: The hairline has receded back to a point between the limit of IIA and the level of the external auditory meatus.

IVA: The hairline has receded beyond the external auditory meatus but has not reached the vertex.

VA: The area of hair loss includes the vertex. Hair loss more severe than VA cannot be distinguished from Types VI or VII.