Cribriform plate

The cribriform plate of the ethmoid bone (horizontal lamina) is received into the ethmoidal notch of the frontal bone and roofs in the nasal cavities.

Projecting upward from the middle line of this plate is a thick, smooth, triangular process, the crista galli, so called from its resemblance to a cock's comb.

The long thin posterior border of the crista galli serves for the attachment of the falx cerebri.

Its anterior border, short and thick, articulates with the frontal bone, and presents two small projecting alæ, which are received into corresponding depressions in the frontal bone and complete the foramen cecum.

Its sides are smooth, and sometimes bulging from the presence of a small air sinus in the interior.

On either side of the crista galli, the cribriform plate is narrow and deeply grooved; it supports the olfactory bulb and is perforated by foramina for the passage of the olfactory nerves. The foramina in the middle of the groove are small and transmit the nerves to the roof of the nasal cavity; those at the medial and lateral parts of the groove are larger—the former transmit the nerves to the upper part of the nasal septum, the latter those to the superior nasal concha.

At the front part of the cribriform plate, on either side of the crista galli, is a small fissure which is occupied by a process of dura mater.

Lateral to this fissure is a notch or foramen which transmits the nasociliary nerve; from this notch a groove extends backward to the anterior ethmoidal foramen.