This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Eye, Nose and Ear, Subject name: Anatomy
Which of the following is NOT a content of medial wall of middle ear - 
Select and explain. 
A. Oval window, B. Round window, C. Processus cochleariformis, D. Aditus ad antrum
D: Aditus ad antrum
Answer: D: Aditus ad antrum 
Explanation: Medial / labyrinthine wall of middle ear. Seperates middle ear from inner ear. Structures present - Promontory - Fenestra vestibuli - Prominence of facial canal - Fenestra cochlea - Sinus tympani - Processus cochleariformis - Prominence of lateral semicircular canal - Round window - Oval window Aditus ad antrum is located on posterior wall Notch of rivinus is located on lateral wall.