nasal passage A channel for airflow through the nose. The walls of the nasal passages are coated with respiratory mucous membranes, which contain innumerable tiny hair-like cells that move waves of mucus toward the throat. Dust, bacteria, and other particles inhaled from the air are trapped by the mucus in the nose, carried back, swallowed,…
nasal polyp A growth or protrusion of tissue in the nose or sinuses. Nasal polyps may produce no symptoms or may lead to obstruction of the nasal passages, sinus infection, and a decreased sense of smell. Nasal polyps are almost always benign. Treatment can involve medications or surgery.
nasal septum The dividing wall that runs down the middle of the nose, separating the two nasal cavities, each of which ends in a nostril. The nasal septum is composed of bone, cartilage, and membranes.
nasal septum, deviated Failure of the nasal septum to be in the center of the nose and divide the nasal passages evenly. Deviation of the nasal septum may be congenital (present at birth) or acquired (occur later). The major problem it causes is airway obstruction. A deviated septum can be corrected with surgery.
nasal septum, perforated A condition in which the dividing wall between the two main nasal passages has been eroded away, resulting in a communication between the passages. Perforated nasal septum can be caused by a number of conditions, including repeated inhalation of cocaine and other harmful drugs. It can usually be repaired with surgery.
naso- Prefix referring to the nose, as in nasogastric tube (a tube that is passed through the nose and to the stomach).
nasogastric Referring to the passage from the nose to the stomach. Abbreviated NG.
nasogastric tube A tube that is passed through the nose and down through the nasopharynx and esophagus into the stomach. Abbreviated NG tube. It is a flexible tube made of rubber or plastic, and it has bidirectional potential. It can be used to remove the contents of the stomach, including air, to decompress the stomach,…
nasopharynx The area of the upper throat that lies behind the nose. See also oropharynx.
myocardium The heart muscle.
myoclonic twitch A rapid, involuntary muscle contraction, particularly near the eye. Myoclonic twitches resemble and may be mistaken for tics. Like tics, they tend to occur more often when the person is under stress; unlike tics, they are not preceded by any sensation and they cannot be delayed.
myoclonus The shock-like, involunatary contraction of a muscle. See also myoclonic twitch.