Clinical Audiology: Hearing assessment

Ear-canal atresia could result in hearing loss of ………. .

a). 20 dB 
b). 20 to 30 dB
c). 30 to 35 dB
d). 55 to 70 dB
e). > 70 dB

Clinical Audiology: Hearing assessment

Impacted cerumen could result in hearing loss of ………. .

a). < 20 dB

b). 20 to 30 dB

c). 30 to 35 dB

d). 55 to 70 dB

e). > 70 dB

Anatomy of Ear: Auricle

How many intrinsic muscles are found in the auricle _____?

a). three
b). nine
c). six
d). ten
e). four

correct answer: c

The intrinsic muscles of auricle are:

1. The Helicis major is a narrow vertical band located on the anterior margin of the helix. It arises from the spina helicis, and is inserted into the anterior border of the helix.

2. The Helicis minor is an oblique bundle and covers crus helicis.

3. The Tragicus is a short, flattened vertical band on the lateral surface of the tragus.

4. The Antitragicus from the outer part of the antitragus, and is inserted into the cauda helicis and antihelix.

5. The Transversus auriculae is placed on the cranial surface of the pinna. It consists of scattered fibers, extending from the eminentia conchæ to the prominence corresponding with the scapha.

6. The Obligus auriculae is found on the cranial surface, extending from the upper and back part of the concha to the convexity immediately above it.

Auditory Physiology: Outer ear

1. The concha of the auricle serve as a resonator enhancing sounds around _____.

a). 4500 - 5000 Hz

b). 2700 - 3500 Hz

c). 800 - 1200 Hz

d). 5000 - 6000 Hz

2. The average gain provided by concha is _____.

1. Correct answer: a

2. Correct answer: 10 dB

Anatomy of Ear: Auricle

Extrinsic muscles of the auricle are _________, _________, and _________.

Answer:
Auricularis Anterior: It is thin and fan-shaped, and arises from the lateral edge of the epicranial aponeurosis, and project on the front of the helix.

Auricularis Posterior: It consists of two or three bundles, and arise from the mastoid portion of the temporal bone by short aponeurotic fibers and insert into the lower part of the cranial surface of the concha

Auricularis Superior: It is thin and fan-shaped, and arise from the epicranial aponeurosis, and converge the upper part of the cranial surface of the auricule.

Anatomy of Ear: Auricle

Auricle is predominantly made up of _______.

a). Elastic cartilage
b). Fibrocartilage
c). Muscle
d). Bone








correct answer: a

Anatomy of Ear: Auricle

Auricle is attached to the skull (from posterior) at an angle of ______ degrees.

a). 45
b). 30
c). 15
d). 90
e). 60







correct answer: b

Auditory Physiology: Outer ear

The auricles are important for

a). Sound localization in verticle plane
b). Sound localization in horizontal plane
c). Front-Back localization
d). All of the above
e). Both a and c



Answer

Auditory Physiology: Outer ear

correct answer: e


The auricles collect the sound waves and funnel them to the external auditory canal. The various folds in the auricle boost high-frequency components and modify the spectral shape of the sound. These spectral shape cues are the major cues in vertical localization. Further, high frequency sounds are boosted by auricle when they arrive from the front, while, the high frequency sounds are attenuated when they arrive from back. The difference in the spectrum provides a cue for front-back localization.

The role of pinna for localization of sound in the horizontal plane may be considered to be minimal. As the interaural phase or time difference (resulting due to the distance between the two ears, as sound takes more time to reach farther ear) and interaural intensity difference (due to head shadow effect) are the major cues for localization.