Question:easy
All of the following are pneumatic bones except?
All of the following are pneumatic bones except?
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Pneumatic bones enclose paranasal sinuses; the mandible has no air sinus.
Updated On: Jun 24, 2026
- Frontal
- Ethmoid
- Mandible
- Maxilla
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The Correct Option is C
Solution and Explanation
Work from the definition: a pneumatic bone is one that houses an internal air space, a sinus, which lightens the bone, gives the voice resonance, and conditions inhaled air. Identifying the odd one out means finding the listed bone that has no such air cavity.
In the skull, the bones built around the paranasal sinuses are the classic pneumatic bones. These are the frontal bone with its frontal sinus, the ethmoid bone with its ethmoidal air cells, the sphenoid with its sphenoidal sinus, and the maxilla with its large maxillary sinus.
Check the four options against that set. Frontal qualifies because of the frontal sinus. Ethmoid qualifies because of the ethmoidal air cells. Maxilla qualifies because of the maxillary sinus. The mandible, however, is a solid bone of the lower jaw with no paranasal air cavity, so it is not pneumatic.
The exception, and therefore the answer, is the mandible.
\[\boxed{\text{Mandible}}\]
In the skull, the bones built around the paranasal sinuses are the classic pneumatic bones. These are the frontal bone with its frontal sinus, the ethmoid bone with its ethmoidal air cells, the sphenoid with its sphenoidal sinus, and the maxilla with its large maxillary sinus.
Check the four options against that set. Frontal qualifies because of the frontal sinus. Ethmoid qualifies because of the ethmoidal air cells. Maxilla qualifies because of the maxillary sinus. The mandible, however, is a solid bone of the lower jaw with no paranasal air cavity, so it is not pneumatic.
The exception, and therefore the answer, is the mandible.
\[\boxed{\text{Mandible}}\]
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