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What is Which si true regarding Torus tubaris? and explain in detail?
Ref. Diseases of Ear, Nose and Throat. Pg 239
 
Torus tubarius or cushion of the auditory canal is a mucosal elevation in the lateral aspect of the nasopharynx, formed by the underlying pharyngeal end of the cartilaginous portion of the Eustachian tube.

The opening of the Eustachian tube is anterior to the torus tobarius.
Immediately posterior to the torus tubarius is the fossa of Rosenmuller.  

From the inferior aspect of the torus tubarius, two mucosal folds extend inferiorly:

anterior fold: the salpingiopalatine fold, which overlies salpingopalatine muscle fibres
posterior fold: salpingopharyngeal fold, which overlies the salpingopharyngeus muscle

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