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What is Posterosuperior retraction pocket if allowed to progress will lead to and explain in detail?
Posterosuperior retraction pocket: the outer layer of the tympanic membrane is lined by stratified squamous epithelium which after invagination forms the matrix of cholesteatoma and lays down the keratin in the pocket. Invagination of pars flaccida: Persistent negative pressure in the attic causes a retraction pocket which accumulates keratin debris. When infected, the keratin mass expands towards the middle ear. This attic perforation is, in fact, the proximal end of an expanding invaginated sac. Ref: Textbook of diseases of ENT, PL Dhingra, 7th edition, pg no. 74