Development of the ear
The ear is a complex organ that serves mainly for hearing and balance. The ear is divided into three main parts. The inner ear consists of the Cochlea, the semicircular canals, and the vestibule. Next, is the middle ear, which consists of the tympanic cavity and the Eustachian, and the external ear, made up of the ear's cartilage and skin.
The embryological development of the ear starts with the inner ear at around 22 days of fertilization. It starts with the appearance of otic placodes, which are thickenings of the surface ectoderm that appears on each side of the rhombencephalon. The otic placodes develop into vesicles, also called osteocytes, which later give rise to the parts of the inner ear. The middle ear forms from all the embryonic germ layers, which are the endoderm, mesoderm, and ectoderm, whereas the external ear develops from the ectoderm, specifically from the mesenchymal proliferation of the first and second pharyngeal arches.