Radiology of external ear: indications, normal anatomy, and pathological processes

The external ear is accessible to direct examination; the clinical history and otoscopy are sufficient to diagnose and treat most diseases of the external ear. We aim to describe the normal anatomy of the external ear, specify the indications for imaging tests, and review the clinical and radiological manifestations of the most common diseases affecting the external ear. We classify these diseases according to their origin into congenital, inflammatory, infectious, or traumatic disease or benign bone tumors or malignant tumors. Imaging does not play an important role in diseases of the external ear, but in certain clinical scenarios it can be crucial for reaching a concrete diagnosis and establishing the best treatment. Computed tomography is the first-choice technique for most diseases. Magnetic resonance imaging complements computed tomography and makes it possible to differentiate among different tissue types and to evaluate the extension of disease accurately.