The joint that permits nodding of head while saying yes is:
High-Yield Explanation
Atlanto-occipital joint is a synol between skull and C1 veebrae. It permits nodding of head such as flexison and extension (YES movement) and lateral flexion. Atlanto-axial joint is a pivot joint between C1 and C 2 veebrae. It permits rotation of head that is side to side movement (NO movement). Ref: Keith moore clinical anatomy, 4th Edition, Page 459.