gag reflexe?? - azamine

[ArchivalUser]

could u explain to me this reflexe

[ArchivalUser]

Gaa refex uses sensory fibers from CN 9 & motor fibers from CN10.

To test for gag reflex...take a tongue depressor & touch the posterior 1/3 of the tongue or lateral wall of oropharynx at the level of palato pharyngeal arches ...that stimulates the mucous membrane of pharynx ...so the entire pharynx constricts...coz the entire pharynx is innervated by CN10.

CN9 is a major sensory nerve which provides general sensory sensation( pain, temp & touch) to pharynx & taste sensation to tongue.

So the loss of gag reflex is a reliable indicator of CN9 lesion....taht indicates the loss of general sensation to pharynx.

But loss of gag reflex is also seen in CN 10 lesion along with other signs

In CN 10 lesion...loss of Gag reflex, loss of cough reflex, nasal reguritation, hoarseness of voice, dysphagia, Uvula deviates to opposite side.

In ipsilateral lesion of CN9 & CN 10 ---u have loss of gag reflex & uvula deviates to opposite side.

so when u can not elicit a Gag....that indicates lesion of CN 9 & lesion of CN 10.

Only in CN 10 lesion uvula deviates away from the lesion side.

[ArchivalUser]

First line it is Gag...not gaa ...sorry for the typo.

[ArchivalUser]

thancks ut i thinck CN9 provide general sensory sensation and taste from only post third of tongue not all

[ArchivalUser]

sorry for the typo...I was in a hurry didnt check it . I know it supplies only posterior 1/3 of the tongue & anterior 2/3 of the tonguue is supplied by CN 7.

CN 9 provides general sensation(pain, temp & touch) to pharynx & taste sensation & general sensation to posterior 1/3 of the tongue.

[ArchivalUser]

isn't the sensory supply to the ant 2/3 of the tongue is by the trigeminal nerve??

[ArchivalUser]

general sensation V3
tastes VII

[ArchivalUser]

yess .... again taste sensation to anterior 2/3 of the tongue.....CN7
general senastion to anterior 2/3 of the tongue...CN V3

Both general sensation to posterior 1/3 of the tongue & taste sensation to posterior 1/3 of the tongue....by CN 9