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Showing posts with the label Ear Nose and Throat

Stridor

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Causes of stridor and management of acute stridor (click to enlarge):

Otitis Media with Effusion (Glue ear)

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Definition: Inflammation of the middle ear with the collection of fluid, without acute signs of inflammation. Also known as glue ear. Pathophysiology:  The pathophysiology of glue ear is not fully known, however it is thought to be associated with Eustachian tube dysfunction. This is either thought to lead to a sterile accumulation of fluids that predisposes the middle ear to infections, or is thought to cause more acute infections of the middle ear that then leads to chronic effusion. Children with cleft palate also often have glue ear as their tensor veli palatini muscle does not attatch properly to the soft palate such that the Eustachian tube does not open on swallowing or mouth opening.

Innervation of the vocal cords

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The vocal cords are innervated by the superior laryngeal nerve and the recurrent laryngeal nerves which are branches of the vagus nerve (cranial nerve X). The superior laryngeal nerve splits into the external and internal branches. The internal branch contains sensory nerves from the larynx whereas the external branch supplies the cricothyroid muscle which tenses the vocal cords. Damage to the superior laryngeal nerves can be caused by thyroid surgery. Unilateral damage to the superior laryngeal nerve causes slight voice changes, usually affecting pitch. Bilateral damage to the superior laryngeal nerves reduces the ability for the vocal cords to close increasing the risk of aspiration. The recurrent laryngeal nerves supply the other muscles of the vocal cords, including the posterior cricoarytenoid muscle which is the only muscle which opens the vocal cords. The recurrent laryngeal nerves have a different course on the left and the right. The left is longer and descends down to...