The ethmoid frequently appears on the dorsal surface between the frontals.
The premaxilla is always unpaired, but each half has three long processes directed backwards; one fuses with the maxillary bone, another helps to form the anterior part of the palate, while the third, together with its fellow, forms the " culmen " and extends backwards to the frontals, or rather to the ethmoid which there crops up on the surface.
ethmoid air cells.
"A Case of a BB-Gun Pellet Injury to the Ethmoid Sinus in a Child."
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