Chapter 19

Question 1

_____ may be due to abnormalities of the hair cells or auditory nerve ganglia [_____] or to structural defects in the external ear canal, eardrum, or ear ossicles [_____]

Answer 1

Congenital hearing loss - sensorineural loss - conductive hearing loss

Question 2

The most common ear ossicle to be involved in conductive hearing loss is the ____, and this fact may be due to its unique origin be- cause its footplate is derived from neural crest cells and paraxial mesoderm

Answer 2

stapes

Question 2

These factors include ____ [rubella, cytomegalovirus, herpes simplex], ____,
and ____. ____ can cause both types of deafness

Answer 2

prenatal infections - prematurity - maternal diabetes - Accutane [retinoids]

Question 3

All of the frequently occurring chromosomal syndromes and most of the less common ones have ear anomalies as one of their characteristics.
True/False

Answer 3

True

Question 3

____ are common; they include minor and severe abnormalities

Answer 3

External ear defects

Question 4

____ are skin tags and shallow depressions, respectively, anterior to the ear

Answer 4

Preauricular appendages and pits