Passavant's ridge is formed by -
It is a mucosal ridge raised by fibres of palatopharyngeus.
It encircles the posterior and lateral walls of the nasopharyngeal isthmus.
Soft palate makes firm contact with this ridge to cut off nasopharynx from oropharynx during deglutition or speech. (Disease of ENT, P.L Dhingra)
Palatoglossus
Superior constrictor
Salpingopharyngeus
Palatopharyngeus