Larynx

The entrance to the larynx (aditus laryngis) is formed at S14. It is just caudal to the tongue primordium and is bounded rostrally by the hypopharyngeal eminence (S17), from which the transverse swelling of the epiglottis develops. The arytenoid prominences are formed in the anterior wall of the pharynx and are caudal to the entrance to the larynx. They restrict the entrance to the trachea so that the opening is shaped like a letter 'T'. Later on, the arytenoid prominences become connected to the lateral edges of the epiglottis and fuse in the median plane. The epiglottis continues up into the nasopharynx where its free end rests against the soft palate. At the same time, the laryngeal opening widens. The larynx sits much higher in a fetus and a newborn baby than in an adult. This is why a newborn baby is able to drink and breathe simultaneously.