TOPIC 2. CAUSES OF HEARING IMPAIRMENT. Outer and Middle Ear Disorders. Structural defects due to embryologic malformations Structural changes secondary to infection or trauma. Outer Ear Disorders. Microtia and atresia. Microtia. “an abnormal smallness of the auricle”. Atresia.
CAUSES OF HEARING
“an abnormal smallness of the auricle”
“the absence of an opening of the external canal”
“a bone disorder that affects the stapes and the bony labyrinth of the inner ear. The disease process is characterized by resorption of bone and new spongy formation around the stapes and oval window”
“an epithelial pocket that forms on the tympanic membrane. Once the pocket forms, the normal shedding of epithelium results in growth of the tumor”
Here’s an example of an audiogram resulting from disarticulation of the ossicular chain
The degree of SNHL depends on