Ear Anatomy
Description
Name
- Ear
General
- Responsible for hearing and maintaining balance
- Can be divided into external, middle and inner ear
External Ear
- Function is to conduct sound to the internal ear
- Key anatomy: auricle (external ear), external acoustic meatus (ear canal)
- Vascular supply: Posterior auricular, anterior auricular, minor branches of the occipital, deep auricular, stylomastoid, inferior tympanic arteries
- Innervation: Auriculotemporal branch of the mandibular nerve, lesser occipital, great auricular nerve, auricular branch of the vagus nerve, branches of the facial nerve
Muscles of the External Ear
- Intrinsic muscles
- Contribute to defining the shape of the auricle by passing between its cartilaginous parts
- Muscles: helicis major, helicis minor, tragus, pyramidal muscle of auricle, antitragus muscle, transverse muscle of auricle, and oblique muscle of auricle.
- Extrinsic muscles
- Play a role in positioning the auricle, originating from the skull and attaching within the auricle itself
- Muscles: auricularis anterior, auricularis superior, and auricularis posterior
Tympanic Membrane
- Often called the eardrum
- Separates the external and middle ear
- Function is to transmit sound/vibrations to the inner ear
Middle Ear
- Separated from the external ear by the tympanic membrane
- Function: Transfers vibrations of the tympanic membrane into sound waves and pass them to the internal ear
- Key Anatomy: tympanic cavity, epitympanic recess
- Vasculature: Anterior tympanic, posterior tympanic, superior tympanic, inferior tympanic arteries, mastoid branch of the occipital artery
- Innervation: Tympanic nerve, tensor tympani nerve, stapedius nerve
- Auditory ossicles: small bones of the middle ear which transmit sound (malleus, incus, stapes)
- Muscles of the inner ear: tensor tympani, stapedius
Auditory Tube
- Also called eustachian or pharyngotympanic tube
- Connects the middle ear and the nasopharynx
- Serves primarily to equalize pressure on both sides of the tympanic membrane
Internal Ear
- Also called the labyrinth, most complex part of the ear
- Cochlea is a spiral shaped, fluid filled structure which turns sound into electrical signals for the brain
- Vestibular system includes semicircular canals, utricle, and saccule helps with posture, balance and coordination
Clinical Significance
- Needs to be updated
See Also
References
- ↑ Image courtesy of otosurgeryatlas.stanford.edu/