Austin's classification for ossicular chain defects depends on

Austin in 1971 Classified ossicular defects based on malleus handle and stapes suprastructure into- Group A- having malleus and stapes intact and erosion of long process of incus being the most common defect. Group B - with only malleus and absent stapes. Group C - with only stapes and absent malleus. Group D - with absent malleus and stapes suprastructure. Ref- Glasscock-Shambaugh surgery of the ear, 5tg edition, PG 463-485.