Search results
Results from the WOW.Com Content Network
The paranasal sinuses are joined to the nasal cavity via small orifices called ostia. These become blocked easily by allergic inflammation, or by swelling in the nasal lining that occurs with a cold. If this happens, normal drainage of mucus within the sinuses is disrupted, and sinusitis may occur. Because the maxillary posterior teeth are ...
The valve of the coronary sinus is a thin, semilunar (half-moon-shaped) valve located on the anteroinferior part of the opening into the right atrium. [5] It is formed by a semicircular fold of the lining membrane of the right atrium. It is situated at the base of the inferior vena cava. [citation needed]
A sinus is a sac or cavity in any organ or tissue, or an abnormal cavity or passage. In common usage, "sinus" usually refers to the paranasal sinuses, which are air cavities in the cranial bones, especially those near the nose and connecting to it. Most individuals have four paired cavities located in the cranial bone or skull.
The Vieussens valve of the coronary sinus is a prominent [1] valve at the end of the great cardiac vein, marking the commencement of the coronary sinus. [2] [1] It is often a flimsy valve composed of one to three leaflets. It is present in 80-90% of individuals. It serves as an anatomical landmark.
The coronary sinus commences at the union of the great cardiac vein, and the oblique vein of the left atrium. [1] [3] [4] The origin of the coronary sinus is marked by the Vieussens valve of the coronary sinus which is situated at the endpoint of the great cardiac vein. [1]
The nasal cavity and the paranasal sinuses are referred to as the sinonasal tract or sinonasal region, and its anatomy is recognised as being unique and complex. [30] [31] Four paired paranasal sinuses – the frontal sinus, the sphenoid sinus, the ethmoid sinus and the maxillary sinus drain into regions of the
The ethmoid sinuses or ethmoid air cells of the ethmoid bone are one of the four paired paranasal sinuses. [1] Unlike the other three pairs of paranasal sinuses which consist of one or two large cavities, the ethmoidal sinuses entail a number of small air-filled cavities ("air cells"). [ 2 ]
A heart valve is a biological one-way valve that allows blood to flow in one direction through the chambers of the heart. A mammalian heart usually has four valves. Together, the valves determine the direction of blood flow through the heart. Heart valves are opened or closed by a difference in blood pressure on each side. [1] [2] [3]