Introduction
The sphenoidal sinuses (lat. Sinus sphenoidalis) are already preformed cavities in the skull of every human, more precisely in the interior of the sphenoidal bone (Os Sphenoidale). The sphenoidal sinus is arranged in pairs, i.e. there is one on the left and another on the right side of the skull.
The two cavities are separated by a septum in the middle. Together with the maxillary and frontal sinus and the ethmoid cells, the sphenoidal sinus belongs to the paranasal sinuses. The sphenoidal sinus is located in the sphenoidal bone (Os sphenoidale) in the so-called cerebral skull.
The bone, in which the two cavities are located, lies deeply shifted to the back, approximately in the middle of the skull. There is a connection between all paranasal sinuses. In addition, they are all in contact with the nasal passage and thus with the external environment.
The sphenoid sinus has its outflow into the upper nasal passage (meatus nasi superior). The inside of the sphenoid sinus is lined with nasal mucosa, which consists of small cilia and continuously produces a rather viscous secretion to keep the inside of the nose and the paranasal sinuses moist and as low in germs as possible. Other important structures in the area of the sphenoid sinuses are the pituitary gland (hypophysis), which rests directly on the roof of the cavity, as well as the main supply artery of the brain (Arteria carotis interna) and the optic nerve (Nervus opticus).
Function
The main function of the sphenoid bone cavity is to save weight by creating air-filled cavities (pneumatization of the bone). The surrounding bone is not exposed to any particular stress in this area, which is why the associated loss of stability in the area of the skull is painful. Other functions (e.g. as a resonance chamber for voice formation) are controversial or have not yet been conclusively clarified.
Causes of inflammation
Due to the connection of the sphenoid sinuses to the outside, infections that originally originate in the area of the nose can migrate into the paranasal sinuses, i.e. also into the sphenoidal sinus. One speaks then of an inflammation of the paranasal sinuses, a sinusitis. In most cases, these inflammations are caused by viral pathogens that have already caused symptoms in the main nasal cavity.
However, bacteria can also be the cause of sphenoid sinusitis or settle secondarily on already weakened areas. Frequently, an accumulation of secretion and pus inside the cavities occurs, since the inflow and outflow path is only a relatively narrow gap. Such an inflammation of the paranasal sinuses becomes noticeable with a feeling of pressure over the forehead and nose as well as under the eyes, headache, a previous or still current cold (rhinitis) and occasionally also fever.
Mostly, the complaints are intensified when bending down and tilting forward. Some patients also report severe earaches. One feels weak and exhausted
