mucous is an adjective. Mucus is a noun.

Mucus Plugs in the Ventral Bronchi Travel Less Distance Than Those ...
... To examine on HRCT whether there is a difference in the respiratory moving
distance of bronchial mucus plugs between ventral and dorsal bronchi. ...
nv-med.com/jrs/journal/ abstract_e.php?bn=20046404&no=2 -

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Note added at 14 mins (2005-04-23 22:42:23 GMT)
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[Plastic bronchitis and mucoid impaction--uncommon disease ...
Mucoid impaction and plastic bronchitis are relatively rare disorders caused by
... impaction--uncommon disease syndromes with expectoration mucus plugs] ...
www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve& db=PubMed&list_uids=11475559&dopt=Abstract

\"Why Are Expiratory Muscle Aids Needed?
\" Although the ability to inspire deeply is very important, the primary muscles for effective coughing are the muscles of expiration or the abdominal muscles. Clearing airway secretions and bronchial mucus plugs may be a continual problem for patients with airway or lung disease and for those who cannot swallow saliva without aspiration. For patients with GAH and functional bulbar musculature it becomes a problem during upper respiratory tract infections, following general anesthesia, and during other periods of bronchial hypersecretion.\"
Quote from John Bach, MD at site below.
http://66.102.7.104/search?q=cache:41K8DzPWomkJ:www.jhemerso...