Type 1 frontal recess cell (Fig 1): They are defined as single anterior ethmoid cells
within the frontal recess sitting above the agger nasi cell.
Onodi cells (FIG 10) are ethmoid cells
that have migrated to the anterior region of the sphenoid sinus, with anterosuperior location, and intimately related to the optic nerve, causing optic neuropathy in case of certain conditions that affect such cells (27).
Ariyurek et al studied 52 patients with normally aerated posterior ethmoid cells
who underwent CT examination prior to endoscopic sinus surgery.
As the dissection progressed, both of these ostia were found to open into the posterior ethmoid cells
Partial multiphase skeletal scintigraphy and single-photon emission CT of the cranium showed increased bone metabolism in the area of the right frontal bone, starting in the ethmoid cells
in the roof of the orbit and extending slightly to the left (figure 2).
However, computed tomography (CT) identified a homogenously enhancing soft-tissue density that involved the right middle and posterior ethmoid cells
and the entire sphenoid sinus.
(3) The anterior and middle ethmoid cells
begin as evaginations from the nasal cavity into the middle meatus at about the third month of fetal development.
The most anterior of the ethmoid cells
, the agger nasi cell is also the first to pneumatize in the newborn, and it is quite prominent throughout childhood.
Dissection of the left posterior ethmoid cells
revealed the presence of a superior Onodi cell (sphenoethmoid cell) above the sphenoid sinus (figure, B).
The anterior ethmoid artery, a branch of the ophthalmic artery, leaves the orbit via the anterior ethmoid foramen, crosses the roof of the anterior ethmoid sinus, and supplies the anterior ethmoid cells
and frontal sinus (figure, A).