Fractures parallel to the petrous ridge are called longitudinal fractures, and those perpendicular to the long axis of the petrous ridge are called transverse fractures [13–15]. In longitudinal fractures, the axis of trauma is lateral, whereas, in trans­verse fractures, it is occipital. In situations such as high-speed motor vehicle acci­dents, the impact involves both lateral and occipital components and the injury may be of a mixed type [15]. The most common type of trauma is longitudinal fractures with a rate of 70–90%, followed by transverse fractures with a rate of 10–30%. The main drawback of this classication is that it does not give an idea of the prognosis, so there are new classications based on whether the otic capsule is preserved or not. In the classication system proposed by Ishman and Friedland, the main crite­rion is whether the petrous bone is involved or not [16]. Otic capsule involvement (5–20%) is an important prognostic criterion and is associated with an increased incidence of facial paralysis, cerebrospinal uid (CSF) leakage, and profound hear­ing loss. Otic capsule-sparing fractures involving the ossicular chain usually result in conductive hearing loss (CHL) or mixed hearing loss [13]. In addition to impact trauma, foreign bodies introduced into the external ear canal may also cause trauma. The most commonly injured structures in this type of trauma are the TM, oval win­dow, and ossicular chain. Before evaluating the fracture on imaging, it is important to know that many anatomic structures are parallel to the fracture lines and will mimic the fracture on imaging. Some of these structures are listed in Table5.2.