[The maxillary sinus: evolution and function in aging]

The maxillary sinus, or Highmore's antrum, is located in the maxillary bone. The maxillary, above the buccal cavity, below the orbital cavity and outside the nasal fossa, is going to take a part in the formation of the three cavities which surround it. Although voluminous, it is consists of a light bone. This distinctive feature is essentially due to the fact that the maxillary has a cavity. The maxillary sinus occupies the upper 2/3s of this maxillary bone. It is the largest of the facial structure's cavities. Its volume is very variable, depending on the individual, the condition of their edentulousness and their age. We find small, average or large sinuses. This sinus communicates with the corresponding nasal fossa by a canal. It opens at the level of the nasofrontalis duct by a meatic ostium, an ostium located at the top of the meatus nasi medius, i.e. under the floor of the sinus. This highly positioned drainage location easily explains the problems that sinus pathologies can come up against. The sinus is lined with a mucous membrane and we can point out that in the normal condition this mucous membrane adheres weakly to the bone. It is more or less thick as a function of the pathologies to which the sinus has been subjected, or even as a function of the geographical location where the individual lives. The imaging of this sinus as a function of age is not obvious due to the fact that it is invisible throughout embryonic and foetal development, and that it only becomes visible to X-rays relatively late, at about 6 years old. Its role is important at the level of the growth of the facial structure because it is always easier to have growth around cavities. It also has a mechanical role concerning the transmission of shockwaves during traumas. In old individuals, due to the condition of the edentulousness, the volume of the sinus is larger; in fact one can note the resorption of the alveolar bone. The maxillary sinus is a cavity which plays a very important role throughout an individual's existence because of the previously mentioned reasons, and which could be used during surgical reconstructions, by the partial filling of this space, to increase the quantity of usable bone (grafts...).