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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Paranasal Sinus
The paranasal sinuses are 4 pairs of air-filled osseous cavities that surround the nose and the orbits and that belong to the maxillary (maxillary sinuses), ethmoid (ethmoid air cells), frontal (frontal sinuses), and sphenoid (sphenoid sinuses) bones, respectively.
