Pneumatisation

Pneumatisation (or pneumatisation) is the process by which certain bones develop air-filled cavities through resorption of bone tissue and expansion by mucosa-lined air spaces. The resulting pneumatic compartments are connected to the nasal cavity or airway via small openings. This process occurs during development and continues into adolescence, contributing to the formation of the paranasal sinuses and other air-containing spaces within the skull, the temporal bone, and, in some cases, other bones such as the frontal bone.

Development and anatomy: Pneumatization begins in fetal life for some structures and expands postnatally. The most notable examples are the paranasal sinuses—maxillary, frontal, ethmoid, and sphenoid—and the mastoid air cell system of the temporal bone. The extent and pattern of pneumatization vary among individuals and can be influenced by genetics, hormonal factors, and environmental influences such as infection or inflammation.

Clinical significance: Normal pneumatization reduces skull weight and provides mucosal surface area for humidifying and warming inhaled air. Hypopneumatization refers to reduced air-space development and can be associated with congenital anomalies or chronic inflammatory disease; hyperpneumatization denotes excessive air-space development and can be observed in certain individuals or conditions that expand cavities. Imaging, especially computed tomography, characterizes the extent of pneumatization and aids in assessing sinus drainage, mastoid aeration, and related pathologies.