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 concha sinus ostia and can result in recurrent sinusitis. Generally, in animals, nasal conchae are convoluted structures of thin bone or cartilage located in the nasal cavity. These are lined with mucous membranes that can perform two functions. They can improve the sense of smell by increasing the area available to absorb airborne chemicals, and they can warm and moisten inhaled air, and extract heat and moisture from exhaled air to prevent desiccation of the lungs. Olfactory turbinates are found in all living tetrapods, and respiratory turbinates are found in most mammals and birds. Animals with respiratory turbinates can breathe faster