The ethmoid has its name because of the Siebbeinplatte ( Lamina cribrosa ), which has numerous holes like a sieve and is found in the facial skull ( Viszerokranium ). The ethmoid bone (ethmoid bone) is a bony structure between the two orbits (orbital) in the skull. It forms one of the central structures of the paranasal sinuses. The internal structure is formed by the air-filled ( pneumatized ) ethmoid cells ( Cellulae ethmoidalis ). The labyrinth of these cells ( Labyrinthus ethmoidale ) is separated by bony septa . The ethmoidal cells can be subdivided into anterior and posterior cells ( ethmoid anterior cell and ethmoid posterior cellula ). The anterior ethmoidal cells have a connection to the middle meatus ( meatus nasi medius ), the posterior to the superior nasal meatus ( meatus nasi superior ). Some authors continue to differentiate and still mention middle ethmoid cells ( ethmoid cellula ).
The ethmoidal cells border (back) at the bottom of the sphenoid sinuses ( sinus sphenoidales ) at the top of the anterior skull base, the frontal bone (frontal bone) and on the ethmoid plate ( lamina cribrosa ), laterally the two eye sockets, in front the middle corner of the eye ( Angulus oculi ) and behind the middle and anterior fossa. There is anatomical proximity to the optic nerve ( optic nerve ). Due to the "paper-thin" wall ( lamina papyracea ) between the eye sockets and the ethmoidal cells, inflammation and tumors can spread in both directions. In the area of the thin ethmoid plate inflammations can rise up to the inside of the skull due to damage.
There are variants regarding the position of ethmoidal cells bearing proper names. The Haller cells are located in the antrum and the Onodi cells are located in the sphenoid sinus, where they lie around the optic nerve canal ( Canalis opticus ).
The ethmoid stabilizes the bony eye sockets, connects them to the olfactory bulb ( olfactory bulb ) and the forehead and separates the cranial cavity and nasal cavity. Together with the nasal septum it separates the nasal cavity into two mirror-like areas, thus allowing a degree of directional creep. Due to the holes in the ethmoid plate, it is possible that the olfactory fibers ( Fila olfactoria ) and blood vessels ( Anterior ethmoid artery, Posterior ethmoidal artery ) may enter the nose to allow perfusion and sensation of the nose. The ethmoidal cells also allow passage for the nervus nasociliaris, a branch of the fifth cranial nerve (trigeminal nerve). This plays an essential role in the transmission of stimuli between the eyes, upper jaw ( maxilla ), lower jaw (mandible) and brain. A bony ledge, the Hahnenkamm ( Crista galli ) divides the sieve plate partially and serves as attachment of the cerebrum ( Falx cerebri ).
The ethmoidal cells participate as a central structure of the paranasal sinuses ( sinus paranasales ) in the air conditioning and the thermal insulation of the airways. Cavitation saves bone and weight. The anterior ethmoidal cells together with the middle nasal meatus and the openings to the maxillary sinuses are part of a functional unit ( ostiomethalic unit ), which contributes to a physiological secretion drainage. These and other functions and tasks are discussed controversially and are part of not yet completed scientific research.
In the healthy state, particles and germs in the mucus are transported by the cell movement, the ciliary beat, towards the exit (ostium, ostiomeatal unit). As part of an inflammation of the ethmoidal cells (ethmoid sinusitis ), the mucous membrane ( respiratory ciliated epithelium ) of ethmoidal cells may swell. This swelling can occlude the exit ( ostium ) and thus disturb the flow of secretion from the maxillary and frontal sinuses (frontal sinus and maxillary sinus ). As a result, germs remain in the other paranasal sinuses and can lead to further inflammation there, so that inflammation and swelling can spread to the frontal and maxillary sinuses.
In a chronic inflammation of the ethmoidal cells and adjacent structures trying to provide by a clearing again for a better secretion drainage. This does not eliminate the entire system of the paranasal sinus, but only swollen mucous membrane and polyps, as well as the thin bony walls between the ethmoidal cells removed. This is performed as an endonasal procedure, ie it is operated only in the inside of the nose, without any external cut. The operation takes place under general anesthesia and the hospital stay usually lasts one week. Followed by a post-treatment to keep the nasal passages open. This can last for three months or more. Swelling, redness or other signs of inflammation are usually no longer visible after the operation, but headaches can occur.
A detailed explanation by the surgeon and the anesthetist before the operation.
One distinguishes benign ( benign ) from malignant ( malignant ) tumors. Benign tumors in the paranasal sinuses are usually bone tumors ( osteomas ) or invaginated wart tumors ( infiltrating papillomas ).
Sieve cell tumors can be caused by environmental influences such as wood dust, chemical fumes or smoke and are recognized as occupational diseases, eg in carpenters. Also genetic factors can not be completely ruled out and are discussed.
Early symptoms of a malignant tumor of ethmoidal cells or other paranasal sinuses may be unilateral nasal obstruction, inflammatory symptoms of ethmoidal cells (swelling, redness, pain, pus) and recurrent, frequent epistaxis . Later, the cheek, eyelids and forehead can swell up. It can also lead to vision problems with double images when the eyeball is displaced by the pressure.
First, a nasal reflection ( rhinoscopy ) to detect a possible tumor directly. Imaging techniques such as x-rays, computed tomography (CT) and magnetic resonance imaging (MRI) can more accurately detect the extent of the tumor. Also, a comprehensive palpation of cervical lymph nodes is essential.
Mostly, a surgical removal of the tumor is advised. In addition, in the case of larger malignant tumors, radiation and chemotherapy are often additionally performed. Small benign osteomas usually require no therapy. However, papillomas grow rapidly and sometimes contain malignant parts. They should therefore be treated just like malignant tumors.
The prognosis varies with the type of tumor, but is usually quite good at early detection. When breaking into surrounding structures, such as the eye socket and the palate ( pterygopalatine fossa ), the prognosis, however, is usually relatively poor.
Depending on the length of the symptoms, one differentiates between an acute (2 weeks duration) and a subacute (more than 2 weeks, less than 2 months duration) chronic (over 2 months duration) inflammation of the ethmoid cells ( sinusitis ). The ethmoidal cells are the only paranasal sinuses that are already present in their complete structure at birth. Therefore, a sinusitis in children mostly in the area of the ethmoid bone and in adults rather in the area of the antrum.
An inflammation of the ethmoidal cells is usually the result of inflammation of the nasal mucosa ( rhinitis or rinosinusitis ), but can also be caused by a tooth root disease . Other causes and favoring factors may include nasal tamponade, closure of the choana ( chonalatresia ), nasal polyps ( polyposis nasi ), tumors, resistance and immunodeficiency, foreign bodies, cystic fibrosis and mucus clearance ( mucociliary clearance ) caused by nose drops. Often there is a bacterial infection. Often it is a mixed infection. A purulent odor indicates an underlying dental disease. In rare cases, fungi can also be the cause.
A characteristic of an inflammation of the ethmoidal cells are pus in the middle nasal meatus, pain, pressure and knock sensitivity at the side of the nose and reduced ability to smell (hyposomy). Radiological imaging (X-rays and computed tomography (CT)) is used for further diagnosis. These usually show a bilateral shading in chronic Siebbeinzellentzündung.
In acute sinusitis, mostly decongestant nose drops, beta-lactam antibiotics and high nasal deposits are recommended.
If inflammation of ethmoid cells or other paranasal sinuses occurs at least twice a year, this is called recurrent acute sinusitis. If computed tomography (CT) shows bilateral shadows on the ethmoidal cells, this may be an indication of chronic inflammation of the ethmoidal cells. Unilateral shading may also indicate a benign tumor.
An inflammation of the ethmoid cells ( sinusitis ) can cause severe pain in the paranasal sinuses. This pain can be triggered and aggravated by stooping, coughing or tapping, ie in situations where pressure is increased. In addition, especially if the maxillary sinuses are affected, there may be tearing and pressure pain on the side of the nose. Often, this pain also radiates into the upper jaw, teeth and skin between the upper lip and lower eyelid.