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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 four paired sinuses or air cavities can be referred to as: Ethmoid sinus cavities which are located between the eyes. Frontal sinus cavities which can be found above the eyes (more in the forehead region). Maxillary sinus cavities are located on either side of the nostrils (cheekbone areas).
There are three pericardial sinuses: superior, transverse and oblique. [1] The superior sinus is anterior to the ascending aorta and the pulmonary trunk. [1] It cannot be assessed in electrophysiology procedures. [1] The oblique sinus is an inverted J-shaped reflection of the venae cavae and pulmonary veins. [2]
The four pairs of paranasal sinuses – the maxillary, ethmoid, sphenoid, and frontal, develop from the nasal cavity as invaginations extending into their named bones. Two pairs of sinuses form during prenatal development and two pairs form after birth. The maxillary sinuses are the first to appear during the fetal third month.
In the anatomy of the heart, the valve of the coronary sinus (also called the Thebesian valve, after Adam Christian Thebesius [1] [2] [3]) is a valve located at the orifice of the coronary sinus where the coronary sinus drains into the right atrium. [4] It prevents blood from flowing backwards into the coronary sinus during contraction of the ...
The internal nasal valve is bounded laterally by the caudal border of the lateral nasal cartilage, medially by the dorsal nasal septum, and inferiorly by the anterior border of the inferior turbinate. [6] The internal nasal valve is the narrowest region of the nasal cavity and is the primary site of nasal resistance. [7]
The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
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]