The Outer Ear Flashcards
11 Parts of the Pinna
- Helix
- Crus
- Lobe
- Triangular Fossa
- Intertragal Notch
- Scaphoid Fossa
- Concha Bowl
- Aperture
- Tragus
- Antitragus
- Antihelix
What does the outer portion of the canal (ear canal) contain?
Cilia (tiny Hairs), Ceruminous glands (wax) and sebaceous (oil) Glands
Adult Ear Canal Length
Varies from 1” to 1 3/8” and 1/4” in diameter
Where the canal becomes narrow as it enters the temporal bone
Isthmus
Average resonant frequency of an ear canal
Aprox. 2700Hz
Where is the vagus nerve (X Cranial Nerve)
Lies along the bottom of the canal, between the outer opening and isthmus
The Size of the eardrum is
Aprox. 1/4” high and 3/8” wide
The three layers of the ED
Skin of the Ear canal, which also likes the outer surface of ED
Fibrous Layer- Outermost fibers are like spokes on a wheel, inner fibers are concentric, all together they support the membrane
Mucous Membrane- Lines the middle ear cavity
What holds the eardrum in place and forming an air/water tight seal between external/middle ear
Annulus or annular ring
Vibrations of sound enhanced by pinna and ear canal resonance and causes ED to move back and forth
Acoustic Energy
What is attached to the ED and is suspended to a point of 2/3 of the way down the drum
Malleus
Point of greatest retraction on ED
Umbo
Atresia
closure of the external Auditory Canal
An inflammation of the walls of the External Auditory Canal that usually do not cause a loss unless the swelling blocks the canal
Otitis Externa
Masses of tissue that grow outward from a surface
Polyps
Look like a hole but reflect light, they were once holes that healed
Monomeric Spots
Occurring in the middle ear and sometimes perforates the upper portion of the ED invading canal, constant odorous discharge
Cholesteatoma
White chalky calcium deposits caused by a degeneration of the tissue on ED
Tympanosclerosis
Bony growths that occur in the ear canal vary in size and location, usually harmless but can pose issues when conducting a HT or during impressions
Exostosis
The Adult Ear canal:
Rises upward and forward then descends to the drum
The isthmus is:
Where the canal narrows to enter the temporal bone
The pinna and the external canal together:
Gather to reinforce acoustical signal
With irregular shape of the auricle, cause increase and decrease at different frequencies as the sound arrives at the ear
Forms a resonating tube
The dividing line between the external ear and middle ear is the:
Tympanic Membrane
Which is not apart of the tympanic membrane
- Pars tensa
- crus
- pars flaccida
- umbo
Crus
Perforations of the ED can be caused by:
An infection
Nearby explosion
Fracture of the temporal bone
What surgical technique repairs the tympanic membrane
Myringoplasty
A cholesteatoma can be described as:
A pouch of skin filled with epithelial debris
A swollen ear may be caused by
Eczema
Otitis externa
Dermatitis
A tympanic membrane perforation may cause a :
Conductive loss
