Ethmoid Bone, Superior View

Description

Seen from a superior aspect, the ethmoid bone sits in the anterior cranial base between the orbital plates of the frontal bone, with the crista galli projecting superiorly in the midline and the cribriform plates spreading laterally to either side. Along the midline, the perpendicular plate descends inferiorly to contribute to the osseous nasal septum, continuous inferiorly with the vomer and the septal cartilage in situ. Anteriorly the ethmoid articulates with the nasal part of the frontal bone, while posteriorly it meets the body of the sphenoid at the planum sphenoidale. Fine detail matters here. This perspective is the one surgeons and radiologists reference when correlating anterior cranial fossa anatomy with the superior nasal cavity, because the perforations of the cribriform plate transmit the olfactory nerve filaments from the nasal mucosa to the olfactory bulbs. Fracture lines across the cribriform region can tear those filaments and the meningeal coverings, a classic mechanism for post-traumatic anosmia and cerebrospinal fluid rhinorrhea. The crista galli also provides a midline landmark for the falx cerebri attachment, helpful when orienting on CT of the skull base. Use this artwork for gross anatomy teaching of the neurocranium and viscerocranium interface, for ENT and neurosurgical texts discussing endoscopic skull base approaches, and for radiology atlases illustrating the anterior cranial fossa and ethmoidal labyrinth relationships. Anatomical accuracy verified by SciePro's Medical Advisory Board.