Frontal air sinuses
| Frontal sinus | |
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Nose and nasal cavities
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| Details | |
| Artery | supra-orbital, anterior ethmoidal |
| Nerve | supraorbital nerve |
| Identifiers | |
| Latin | sinus frontales |
| MeSH | A04.531.621.387 |
| TA | A06.1.03.004 |
| FMA | 57417 |
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Anatomical terminology
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The frontal sinuses are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle nasal meatus of the nose through the frontonasal duct which traverses the anterior part of the labyrinth of the ethmoid. These structures then open into the hiatus semilunaris in the middle meatus.
Frontal sinuses are rarely symmetrical and the septum between them frequently deviates to one or other side of the middle line. Their average measurements are as follows: height 28 mm, breadth 24 mm, depth 20 mm, creating a space of 6-7 ml.
The mucous membrane in this sinus is innervated by the supraorbital nerve, which carries the postganglionic parasympathetic nerve fibers for mucous secretion from the ophthalmic nerve and supplied by the supraorbital artery and anterior ethmoidal artery.
The frontal sinuses are absent at birth, but are generally fairly well developed between the seventh and eighth years, only reaching their full size after puberty. The frontal bone is membranous at birth and there is rarely more than a recess until the bone tissue starts to ossify about age two. Consequently this structure does not show on radiographs before that time. Sinus development begins in the womb, the maxillary and ethmoid sinuses are present at birth. Sphenoidal sinuses are present at birth as well but are very small. Approximately 5% of people have absent frontal sinuses.
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Wikipedia