Roof of middle ear = tegmen tympani, roof of mastoid antrum = tegmen antri (separates ear from middle cranial fossa).
Floor of middle ear = thin plate of bone, separates from jugular bulb.
Anterior wall of middle ear – Eustachian tube opening, canal of tensor tympani (muscle originates here).
Lateral wall of middle ear – tympanic membrane (= medial wall of outer ear).
Scutum – lateral bony wall above the tympanic membrane / lateral wall of attic (cholesteatoma erodes it commonly).
Prussak space – space between the scutum & pars flaccida laterally and neck of malleus medially. Retraction pockets most commonly develop into this area forming cholesteatoma, which later erodes the surrounding bony structures.
Medial wall of middle ear (= lateral wall of inner ear) – promontory (formed by basal coil of cochlea), processus cochleariformis anteriorly (landmark for facial nerve which enters middle ear above it), oval window posterosuperior to promontory (stapes footplate inserts), round window (also called secondary tympanic membrane) posteroinferior to promontory (electrode in cochlear implant inserted through this), facial nerve runs horizontally above oval window till the junction of medial and posterior walls.
Posterior wall of middle ear – pyramid (stapedius muscle arises and inserts into posterior crura of stapes), facial nerve runs vertically and gives chorda tympani branch below the level of middle ear (chorda tympani travels up and enters middle ear, runs between malleus and incus, exits middle ear through canal of huguier in petrotympanic or glasserian fissure lying anteriorly on lateral wall of middle ear, supplies anterior 2/3rd of tongue for taste sensation).
Facial recess (posterior tympanotomy surgical approach) lies between chorda tympani & facial nerve. Incus short process forms superior boundary of facial recess.
Ponticulus – bony elevation connecting promontory and pyramid (PPP).
Subiculum – bony elevation inferiorly.
Sinus tympani – space between ponticulum and subiculum (cholesteatoma here may be missed on ear examination).