9. Ear Flashcards
1. Describe the three general divisions of the ear.
- External ear into two parts;
- auricle (or pinna)
- external acoustic meatus – which ends at the tympanic membrane.
- Middle ear is located in temporal bone, and extends from the tympanic membrane to the lateral wall of the inner ear.
- Inner ear is located within the petrous part of the temporal bone. It lies between the middle ear and the internal acoustic meatus. Two main components:
- Bony labryinth
- membranous labyrinth
Parts of the auricle of the external ear
- Helix/ Antihelix
- Tragus/antitragus
- lobule
- Concha
- Describe the blood supply of the pinna.
External carotid A
- 1. Posterior auricular A.
- 2. Superficial temporal A.
Innervation of the auricle (pinna) of the ear
- Great auricular N
- Auriculotemporal N of trigeminal N (V3)
- Auricular branch of vagus N (CN X)
- Facial N (CN7)
- Internal surface of the tympanic membrane is innervated by CN 9 (glosspharyngeal N)
Internal surface of the tympanic membrane is innervated by ___________
CN 9 (glosspharyngeal N)
Innervation of external surface of tympanic membrane
- Auriculotemporal N (CN V3) innervates 2/3
- Auricular branch of vagus (CN X)
Auricular Hematomas
- Hit on side of ear -> blood accumulates in the perichondrium or cartilage of the ear, it can form a auricular hemotoma.
- This blood needs to be released. Otherwise: form abnormal cartilage -> cauliflower ear.
External Acoustic Meatus
- Extends from _____ to _________
- What is it made out of?
- Extends from concha of auricle to tympanic membrane
- Lateral 1/3 is cartilage; medial 2/3 is bone.
A child’s external auditory meatus is ______ than an adult’s.
shorter.
same size by 4. yo
What is otitis externa?
Otitis externa (swimmer’s ear) is an infection to the external acoustic meatus. D/t
- 1. excessive moisture
- 2. trauma (cleaning/scratching)
- 3. things that block ear canal
- 4. Derm conditions
- 5. radiations
What separates the external ear from middle ear?
TYMPANIC MEMBRANE (ear drum)
The ____________ joins the middle ear to the nasopharynx.
The pharyngotympanic tube (eustachian tube) joins the middle ear to the nasopharynx.
How is the typanic membrane divided?
- Anterior inferior
- Where cone of light is located.
- Anterior superior
- Posterior inferior
- Posterior superior
On the inner surface of the tympanic membrane, the _______ attaches to the tympanic membrane, at a point called the_________
- On the inner surface of the membrane, the handle of malleus attaches to the tympanic membrane, at a point called the umbo of tympanic membrane.
The handle of malleus continues superiorly, and at its highest point, a small projection called the____________.
lateral process of the malleus.
What part of TM is more vascularized?
Superior part
What is otitis media?
- Infection of the middle ear, causing inflammation and swelling of mucous membrane of tympanic cavity -> block pharyngotympanic tube (eustachian tube), which links nasopharynx to middle ear.
- Tympanic membrane will look red and bulge.