Anterior cells of ethmoid bone

At a glance

English

Anterior cells of ethmoid bone

Latin (TA2)

Cellulae anteriores ossis ethmoidei

System

Bone

Region

Whole body

Side

Paired, left and right

About the anterior cells of ethmoid bone

The anterior ethmoidal cells are the foremost of the small air spaces that make up the labyrinth of the ethmoid bone on each side. They sit between the upper nasal cavity and the medial wall of the orbit, behind the lacrimal bone and the frontal process of the maxilla, and just below and behind the floor of the frontal sinus. Their number and size vary a great deal between people and between the two sides of one skull.

Each cell is a thin-walled pocket of bone lined by mucous membrane that is continuous with the lining of the nose. Many of the cells are completed by the neighbouring bones: the frontal bone closes them above, and the lacrimal bone and maxilla close them in front and to the side. The most forward cell often lies within the agger nasi, a small ridge in front of the attachment of the middle concha. Other cells crowd around the route by which the frontal sinus drains, so that their size can narrow or widen that channel.

The anterior group opens into the middle meatus of the nose, mostly into the ethmoidal infundibulum, the groove behind the uncinate process that leads to the semilunar hiatus. The frontal and maxillary sinuses drain into the same small region, which makes it a shared bottleneck: swelling of the lining there can block several sinuses together. The cells are present in a small form at birth and enlarge through childhood with the growth of the face.

Clinically, these cells are central to endoscopic sinus surgery, which opens the infundibulum and the anterior cells to restore drainage. Infection in them can spread through the very thin orbital plate into the orbit, producing swelling around the eye, a pattern seen especially in children. The anterior ethmoidal artery, crossing the roof of this region on its way to the nose, is a landmark surgeons take care to protect.

Function and supply

Nerve supply

The anterior ethmoidal nerve, from the nasociliary branch of the ophthalmic nerve, supplies the lining, with nasal branches of the maxillary nerve; secretory fibres reach it from the pterygopalatine ganglion.

Blood supply

The anterior ethmoidal artery from the ophthalmic artery, with branches of the sphenopalatine artery from the maxillary artery; veins drain to the ophthalmic veins and the nasal venous plexus.