Sinus barotrauma11/3/2022 ![]() ![]() Divers will also experience similar pressure changes as they descend and ascend. Such changes in pressure, and the speed of change, are not normally experienced “on the ground” a rare example concerns travelling on a train as it enters or exits a tunnel at great speed. Some of these changes can be quite rapid. Whether flying in an unpressurised or pressurised aircraft, passengers and crew will experience a decrease in ambient (environmental) pressure whilst climbing, and an increase in pressure during descents. There are several competing hypotheses regarding the biological function and purpose of the paranasal sinuses, but it is possible that they serve no biological function at all. The paranasal sinuses are joined to the nasal cavity via small orifices called ostia these are normally clear and allow pressure to equalise between the sinus cavities and the external environment. The paranasal sinuses are lined with respiratory epithelium which is a moist tissue whose purpose is protection from potential damage caused by mucous movement, and also to act as a barrier to pathogens and particles. the sphenoid sinuses, in the sphenoid bone at the centre of the skull base under the pituitary gland.the ethmoid sinuses, which are formed from several discrete air cells within the ethmoid bone between the nose and the eyes.the frontal sinuses, superior to the eyes, in the frontal bone, which forms the hard part of the forehead.the maxillary sinuses, the largest of the paranasal sinuses, are under the eyes, in the maxillary (cheek) bones.Sinuses are cavities within a bone or other tissue, and humans have many around their bodies.įor flight, we are concerned mostly with the “paranasal sinuses”, which are a group of four paired air-filled spaces that surround the nasal cavity and they are named after the facial bones in which they are located: Paranasal Sinuses (photograph by Hellerhof) Normally the walls of the Eustachian tube are collapsed, and jaw-moving actions such as swallowing, talking, yawning and chewing open the tube to allow air in or out as needed for equalisation. This is achieved via the Eustachian tube which connects the tympanic cavity to the throat/nasopharynx and acts as a pressure release valve to equalise the middle ear pressure to that outside. This means the air pressure within the middle ear must equal that of the external environment. For the eardrum to have maximal mobility, the air pressure on either side must be equal. The tympanic cavity is air-filled and carved out of the temporal bone. ![]() Normal Operation of the Middle EarĮfficient hearing requires an intact tympanic membrane (eardrum), a normal ossicular chain, and a well-ventilated tympanic cavity. This amplification is variable, depending on the frequencies higher frequencies need less amplification for transmission to the cochlea. It is these tiny bones that create the mechanical amplification. stapes (stirrup) which is attached to the oval window.incus (anvil) which links the two other bones.malleus (hammer) which adjoins the eardrum.The eardrum is attached at the umbo to the ossicular chain, which consists of three tiny bones: ![]()
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