Radiology of the head

There is little doubt that the cross-sectional imaging modalities of computed tomography (CT), magnetic resonance imaging (MRI) and diagnostic endoscopy are superior to radiography for the assessment of diseases involving the head. The limitations of radiography for imaging the head are that, whilst it is sensitive for detecting some diseases, it is insensitive for detecting others, and when disease is detected the extent of the changes may be underestimated. Despite this, radiography remains a primary diagnostic technique as it is widely available and inexpensive. The skull is a complex bony structure enclosing the brain and the communicating air-containing structures of the nose, nasopharynx, oropharynx and auditory bulae. Surrounding soft tissue structures are limited to the masticatory muscles, salivary glands and supporting muscles of the neck. Therefore, although the skull has high inherent radiographic contrast and can be imaged using an X-ray tube with limited output, the principle challenge is posed by the superimposition and geometric complexity of the bones of the skull. The chapter examines the radiological interpretation of Nasal cavity and frontal sinuses; Cranium and calvarium; Mandible, maxilla and dentition; Temporomandibular joint; Ears and bullae; Larynx and pharynx; Salivary glands; and Hyoid bones.