The sinuses are air-filled cavities. 1  They are located: 2  Within the bony structure of the cheeks. 3  Behind the forehead and eyebrows. 4  On either side of the bridge of the nose. 5  Behind the nose directly in front of the brain.
An O-ring is a round ring that is used as a gasket for sealing a connection. O-rings are typically constructed out of polyurethane, silicone, neoprene, nitrile rubber or fluorocarbon. These rings are commonly used in mechanical applications, such as pipe connections, and help to ensure a tight seal between two objects. O-rings are designed to be seated in a groove or housing that keeps the ring in place. Once in its track, the ring is compressed between the two pieces and, in turn, creates a strong seal where they meet.
Orbital atherectomy (OA) is another atherectomy device being used for plaque modification, to reduce the total atheroma burden, to change the arterial compliance, and to decrease the vessel-wall trauma.50 The Diamondback 360Â° OAS is very similar to RA devices, as it uses a crown that is equivalent to the RA burr.