6. The mastoid process is an inferior extension of the petrous temporal bone of the skull and provides a structural function as an anchor point for the large muscles of the neck.It contains multiple air cells that develop from a single main cavity (the antrum), after the age of about 2.he infective process causes inflammation of the mastoid and surrounding tissues and may lead to bony destruction. 1  Classic, or acute, mastoiditis is a rare complication of acute otitis media (AOM).