Structure/Morphology
The ethmoidal cells (sinuses) are small air filled spaces located between the orbits within the ethmoid bone. The number of ethmoidal cells can vary from as few as 3 to as many 18 on each side of the skull. Clinically, the cells are divided into anterior and posterior groups. The two groups are separated by the basal lamella. The cells are lined by respiratory epithelium.
Key Features/Anatomical Relations
The ethmoidal cells are connected to the middle meatus of the nasal cavity.
Function
The ethmoidal cells contribute to adding resonance to the voice and decreasing the overall weight of the skull.
List of Clinical Correlates
- Endoscopic sinus surgery
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Ethmoid Sinus
The medial optic canal ring (medial portion of the optic foramen) is a thickening of the orbital medial wall and roof at the junction of the ethmoid and sphenoid sinus, and marks the orbital entrance of the optic canal.
