The cribriform plate or lamina cribrosa in Latin (‘cribrosa’ meaning perforated) is a horizontal sieve-like plate that belongs to the cuboidal and fragile ethmoid bone. It separates the floor of the anterior cranial fossa from the nasal cavity and fills the ethmoidal notch of the frontal bone, forming a large portion of the nasal roof. It is penetrated by numerous foramina that transmit the olfactory nerves (CN I) along with its surrounding sleeves of dura mater and arachnoid mater, to the olfactory bulb of the brain.
The crista galli is a thick, smooth, triangular median process that projects upward from the center of the cribriform plate. It is called so due to its resemblance to a rooster’s comb. The falx cerebri, one of the meningeal layers of the dura mater, attaches to the thin and curved posterior border of the crista galli. The short and thick anterior border however articulates with the frontal bone through two small processes, completing the foramen caecum. Small bulges belonging to the underlying ethmoid air cells may show on its sides, but otherwise it has a smooth surface. The cribriform plate is narrow and deeply grooved on both sides of the crista galli, and is related to the gyrus rectus and the olfactory bulb lying above. A small slit occupied by dura mater exists anterior to the cribriform plate, on either side of the crista galli. The anterior ethmoidal nerve (arising from the nasociliary nerve) and vessels pass towards the nasal cavity through a foramen located anterolateral to said slit.
Fractures in the floor of the anterior cranial fossa may involve the cribriform plate. This can cause the leakage of the cerebrospinal fluid from the nose, a condition called ‘CSF Rhinorrhea’.
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