The external auditory meatus develops from the dorsal portion of the first pharyngeal cleft. The epithelial cells at the bottom of the meatus proliferate, forming the meatal plug, which dissolves later on.
The tympanic membrane is made up of the ectodermal epithelial lining at the bottom of the auditory meatus, the endodermal epithelial lining of the tympanic cavity, and an intermediate layer of connective tissue derived from the mesenchyme.
The auricle develops from six mesenchymal proliferations of the first two pharyngeal arches, which surround the first pharyngeal cleft. Initially, the external ears are located in the lower neck region, but subsequently ascend to the level of the eyes. |
