The overgrowth of the second pharyngeal arch over the third and fourth arches leads to a smooth neck contour by burying the clefts. What feature results from this process?

• A. A smooth neck contour
• B. A laterally displaced SCM
• C. A scaphoid neck
• D. An anterior neck mass

Answer: (A)

During development, the second pharyngeal arch overgrows the third and fourth arches, burying the cervical clefts and obliterating the cervical sinus. This results in a continuous, smooth contour of the neck because there are no persistent epithelial clefts or tracts disrupting the neck’s surface. If the sinus fails to obliterate, you’d expect a branchial cleft cyst or fistula along the neck, often presenting as a lateral neck mass. Therefore, the feature produced by this process is a smooth neck contour.