Summary of Development of the ear
The otic placodes are the first signs of the developing ear. They are thickenings of the surface ectoderm on each side of the rhombencephalon, and develop into otic vesicles, or otocysts. These will later give rise to the inner ear, and divide into a ventral part, generating the saccule and cochlear duct, and a dorsal component, making the utricle, semicircular canals and endolymphatic duct. The middle ear has an endodermal origin, the auditory tube, tympanic cavity and epitympanic recess, and a mesenchymal origin, the ossicles. The auricle instead develops from six mesenchymal proliferations, termed auricular hillocks, and the external auditory meatus develops from first pharyngeal cleft ectoderm.