A 5-day-old female infant was born with a laryngeal defect. The greater cornuae and the inferior pa of the hyoid bone were absent at bih. Failure of development of which of the following embryonic structures has most likely led to these defects?

The third pharyngeal arch gives rise to the greater cornuae and lower pa of the hyoid bone, in addition to the stylopharyngeus muscle. The maxillary prominence of 1st Arch is impoant in the development of the cheeks and upper lip. The mandibular prominence of 1st Arch is impoant in development of the mandible. The second pharyngeal arch gives rise to the lesser cornu and upper pa of the hyoid bone. The fouh pharyngeal arches, while extensively involved in development of the cailage and muscles of the larynx, play no pa in the development of the hyoid bone.