Stertor () is a term first used in 1804 to describe a noisy breathing sound, such as

snoring Snoring is an abnormal breath sound caused by partially obstructed, turbulent airflow and vibration of tissues in the upper respiratory tract (e.g., uvula, soft palate, base of tongue) which occurs during sleep. It usually happens during in ...

.O Cathain E, Gaffey MM
Upper Airway Obstruction
In: StatPearls. StatPearls Publishing, Treasure Island (FL); 2020. It is caused by partial obstruction of the upper

airway The respiratory tract is the subdivision of the respiratory system involved with the process of conducting air to the alveoli for the purposes of gas exchange in mammals. The respiratory tract is lined with respiratory epithelium as respiratory ...

s, at the level of the

nasopharynx The pharynx (: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its ...

oropharynx The pharynx (: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates, though its ...

. It is distinguished from

stridor Stridor () is an extra-thoracic high-pitched breath sound resulting from turbulent air flow in the larynx or lower in the bronchial tree. It is different from a stertor, which is a noise originating in the pharynx. Stridor is a physical sig ...

by its pitch. Stertor is low-pitched, and can occur when breathing in,

out Out or OUT may refer to: Arts, entertainment, and media Films *Out (1957 film), ''Out'' (1957 film), a documentary short about the Hungarian Revolution of 1956 *Out (1982 film), ''Out'' (1982 film), an American film directed by Eli Hollander *O ...

or both. Stertor and stridor can occur together, such as when adenotonsillar hypertrophy and laryngomalacia occur together.

References

Respiration {{Med-sign-stub