The lamina cribrosa or cribriform plate is the horizontal superior boundary of the bone. This perforated plate forms the roof of the nasal cavity and part of the floor of the anterior cranial fossa. It is rectangular, being longer in the anteroposterior axis. The plate is thin and perforated by many small foramina. These foramina transmit the olfactory nerves from the olfactory bulb above the plate, to the superior aspect of the nasal cavity below the plate.

The term lamina is Latin for plate, leaf, or thin scale. Foramen is the Latin term designating a hole-like opening. It derives from the Latin forare meaning to bore or perforate. Cribrosa comes from the Latin cribrum meaning sieve.