MeSH A04.531.621.267 TA A06.1.03.005 | Dorlands
/Elsevier c_19/12225634 FMA 71958 | |
 | ||
Nerve posterior ethmoidal nerve Latin Cellulae ethmoidales,
labyrinthi ethmoidales | ||
The ethmoidal sinuses or ethmoidal air cells of the ethmoid bone are one of the four paired paranasal sinuses. They are a variable in both size and number of small cavities in the lateral mass of each of the ethmoid bones and cannot be palpated during an extraoral examination. They are divided into the anterior, middle and posterior groups (see below). The ethmoidal air cells consist of numerous thin-walled cavities situated in the ethmoidal labyrinth and completed by the frontal, maxilla, lacrimal, sphenoidal, and palatine bones. They lie between the upper parts of the nasal cavities and the orbits, and are separated from these cavities by thin bony laminae.
Contents
Groups of sinuses
The groups of the ethmoidal cells are air cells:
Development
The ethmoidal cells (sinuses) are present at birth, however by 2 years of age they are recognisable through the use of Computerised Tomography (CT) scanning.
Innervation
The ethmoidal air cells receive sensory fibers from the anterior and posterior ethmoidal nerves, and the orbital branches of the pterygopalatine ganglion, which carry the postganglionic parasympathetic nerve fibers for mucous secretion from the facial nerve.
Haller cell
Haller cells are infraorbital ethmoidal air cells lateral to the lamina papyracea. These may arise from the anterior or posterior ethmoidal sinuses.
Pathology
Acute ethmoiditis in childhood and ethmoidal carcinoma may spread superiorly causing meningitis and cerebrospinal fluid leakage or it may spread laterally into the orbit causing proptosis and diplopia.