Passavant ridge is formed by

Passavant ridge Near the superior margin of the pharynx, a few fibers of superior constrictor blend with a band of muscle fibers belonging to the palatopharyngeus muscle These fused fibers form a band or ring around the posterior wall and sidewalls of the nasopharyngeal isthmus When the soft palate is elevated this muscle band appears as a ridge is known as passavant ridge. Ref: PL Dhingra, Diseases of Ear, Nose & Throat, 7th edition, pg no. 271