The middle cranial fossa dural plate is an important surgical landmark, especially during tympanomastoidectomy. The risk of iatrogenic dural plate trauma or other dural injuries is high in patients with a low dural plate. This may cause serious complications such as cerebrospinal fluid leakage, epidural abscess, meningitis, brain abscess, and encephalocele or meningocele. 1-5 Awareness of level of tegmen particularly if it is low in position is very important for the 
surgeon in the preoperative period and may be more meaningfully evaluated with the depth of the dural plate beyond the point of greatest protrusion of the superior semicircular canal into the middle cranial fossa. If the tegmen height was known to be low from measurements made in the preoperative period, it would alert surgeons to the risk and ensure appropriate care was taken. 
The aim of this study is to illustrate the level of tegmen in patients with chronic otitis media (COM) and to study different 
factors that can affect depth of middle cranial fossa dural plate in a hope to illustrate risk factors that danger this 
important surgical landmark during ear surgery.