Facial recess or the posterior sinus is bounded by -

Facial recess or Posterior sinus – It is a depression in the posterior wall of the middle ear. It is bounded by: Medially – Vertical part of VIII nerve Laterally – Chorda tympani Above – Fossa incudis Importance – This recess is important surgically, as direct access can be made through this into the middle ear without disturbing posterior canal wall. (Posterior tympanotomy approach)