They join together to form a solid, bony cavity protecting the brain and supporting the structures of the head.

Each year, about 31 million people experience sinus infections, which are usually caused by bacteria growing in the sinuses, the bony cavities found behind the nose, eyes, brows, and cheekbones.

This specialized focus deals with the management of deformities and abnormalities of the eyelids, lacrimal (tear) system, the orbit (the bony cavity surrounding the eye), and the adjacent face.

Within the osseous vestibule, the membranous labyrinth does not quite preserve the form of the bony cavity, but consists of two membranous sacs, the utricle, and the saccule.

It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity (sella turcica) covered by a dural fold (diaphragma sellae).

Sir Clifford's whale has been articulated throughout; so that, like a great chest of drawers, you can open and shut him, in all his bony cavities --spread out his ribs like a gigantic fan --and swing all day upon his lower jaw.