ABSTRACT
The temporal bone consists of five osseous components: the squamous, mastoid, petrous, tympanic, and styloid parts. The external auditory canal, with lateral one-third cartilaginous and medial two-thirds bony composition, extends from the auricle to the tympanic membrane. The nasal cavity is divided into two by a septum that is cartilaginous anteriorly and bony posteriorly. The paranasal sinuses are characterized as air-filled spaces between the bones around the nasal cavity. Maxillary and ethmoid sinuses are aerated at birth. The frontal sinus is absent at birth. Pneumatization occurs between the first and twelfth years. An inflammatory process of the middle ear and mastoid may occur due to Eustachian tube dysfunction or obstruction, or viral or bacterial infection. Esthesioneuroblastoma, an uncommon malignant tumor of neural crest origin, arises from neuroendocrine cells within the olfactory epithelium of the superior nasal cavity. Nasopharyngeal carcinoma, which is the most common nasopharyngeal tumor in adults, has squamous cell origin and male predominance.
