Prussack space

This space is named after the Russian otologist Alexander Prussak.
This is a small middle ear recess which lies medial to the pars flaccida.
Boundaries:
Superiorly: Scutum and lateral malleolar ligament
Lateral: Pars flaccida
Inferior: Lateral process of malleus
Medial: Neck of the malleus
It communicates with the posterior pouch of Troeltsch.
Clinical significance:
Cholesteatoma invariably starts in this space. It begins as a retraction pocket involving pars flaccida. Cholesteatoma from this space spreads via:
Posterior epitympanum through the superior incudal space to involve the mastoid antrum.
Posterior mesotympanum: Inferiorly via the pouch of Von Troeltsch to involve stapes, round window, sinus tympani and facial recess.
Anterior epitympanum: Anterior to head of malleus it can gain access to supratubal recess via the anterior pouch of Von Troeltsch.