Post-nasal drip Post-nasal drip Post-nasal drip (PND, also termed upper airway cough syndrome, UACS, or post nasal drip syndrome, PNDS) occurs when excessive mucus is produced by the nasal mucosa. The excess mucus accumulates in the back of the nose and eventually the throat once it drips down the back of the throat. It is caused by rhinitis, sinusitis, gastroesophageal reflux disease (GERD), or by a disorder of swallowing (such as an esophageal motility disorder). But also further sources such as an allergy, cold or flu and as a result of medications. However, researchers argue that the flow of mucus down the
Nasal cavity the nasal cavity. In some animals, such as dogs, the capillary beds flowing through the nasal cavity help cool the blood flow to the brain. Blood supply comes from branches of both the internal and external carotid artery, including branches of the facial artery and maxillary artery. The named arteries of the nose are: Innervation of the nasal cavity responsible for the sense of smell is via the olfactory nerve, which sends microscopic fibers from the olfactory bulb through the cribriform plate to reach the top of the nasal cavity. General sensory innervation is by branches of the trigeminal nerve