Ear AnatomyThere’s a lot more to our ears than experiencing the pleasure of listening to our favorite song or the birds singing early in the morning. In fact, maintaining our balance might be just as important, allowing us to stand, run, and dance!
The ear is divided into three parts; the external ear, the middle ear, and the inner (internal) ear. In this article, we will help you approach the anatomy of the ear in the most effective way possible using the beautiful content of Kenhub. Let’s get started!
External ear anatomy
The auricle, the external acoustic meatus (canal), and the tympanic membrane are the structures that comprise the external ear with the sole function of conducting sound waves to the middle ear after tuning their acoustic pressure.
It’s funny that the large, fleshy, weird-looking structures on the lateral aspect of our heads that we call ears, are actually just the auricles. Also called pinna, the auricle is the only part of the ear that is not contained within the head. It consists of elastic cartilage covered by skin, and is supported by ligaments as well as the extrinsic and intrinsic muscles of the external ear. Its main function is to channel the sound waves into the external auditory meatus.
External acoustic meatusThe external acoustic meatus is the 2-3 cm canal extending from the auricle to the tympanic membrane. Its external (lateral) one third is cartilaginous and has the ceruminous glands that produce earwax, while its internal (medial) two-thirds is bony and significantly narrower.
Tympanic membrane (eardrum)
Located at the medial end of the external acoustic meatus, the tympanic membrane is a thin membrane that vibrates in response to sound waves. It transmits sound waves into the middle ear. To enhance your knowledge on the anatomy of the external ear, make sure to check out our article and take our brilliant quiz!
Middle ear anatomy
Separated from the external ear by the tympanic membrane (eardrum), the middle ear is an air-filled cavity residing within the petrous part of the temporal bone. The pharyngotympanic tube (eustachian tube) connects the middle ear with the nasopharynx, while the mastoid antrum connects it with the mastoid air cells.
The middle ear contains the auditory ossicles (i.e. ear bones), tendons of the stapedius and tensor tympani muscles, the chorda tympani nerve, and tympanic plexus.
Want to strengthen your information about the middle ear? Make sure to read both of our articles:
Inner ear anatomy
While the external ear and middle ear are more concerned with the transmission of sound, the inner ear contains the organ of hearing and balance (i.e the vestibulocochlear organ). It consists of a bony labyrinth and a membranous labyrinth.
The bony labyrinth forms hollow bony cavities within the temporal bone whilst the membranous labyrinth is the inner system of fluid filled ducts and sacs. The vestibule, three semicircular canals, and cochlea comprise the perilymph filled bony labyrinth. The membranous labyrinth sits within the bony labyrinth and is formed by the cochlear duct, semicircular ducts, and two sacs; the utricle and the saccule. The membranous labyrinth is filled with endolymph. The vestibule contains the utricle, the saccule and the semicircular ducts, all of which are responsible for our sense of balance and position. The cochlea houses the cochlear duct which contains the organ of Corti; the receptor organ for hearing.
The vestibulocochlear nerve (CN IIX) delivers sensory information coming from the inner ear to the brain. It consists of two parts: the vestibular part which carries nervous impulses from the vestibular system, and the cochlear part which carries impulses from the cochlea. Both of these structures are part of the ear.
Read more about the anatomical details of the internal ear in our comprehensive articles and don’t forget to take our quiz to reinforce your knowledge.