<prompt> Grisel;s syndrome isGlucosaminidase deficiencyAtlanto-axial joint dislocationHexosaminidase deficiencyL4-L5 displacement  <response>: Grisels syndromeSpontaneous subluxation of the atlantoaxial joint following peri-pharyngeal inflammation is known as Grisels syndrome Children are most frequently affected and classically have toicollis associated with neck stiffness or pain upon neck movementRefer: Nelsons Textbook of Pediatrics, SAE, 1st edition, pg no. 3297, 3298 