A discrete bulging or local rupture in the basal lamina which allows a cell process to cross to the â€œwrongâ€ side of a tissue border. The same term might be used to describe a discrete bulging in any other thin membrane or tissue. See Basal lamina See Fenestration
In neurology, used to describe the movement of brain tissue through or across small openings due to increased intracranial pressure.
Any abnormal bulge of a body part may be referred to as a hernia and the process of bulging is called herniation.