I

Mild deformity where shoulder girdles are at the same level. The deformity is not visible in the dressed patient

II

Slight deformity still present, where shoulder joints are almost level, but superomedial portion of scapula visible as a lump

III

Moderate shoulder joint deformity with scapula visibly elevated 2–5cm

IV

Severe deformity with scapula angle close to the occiput with webbing of the neck