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External Ear
Audiology PowerPoint 3
| Question | Answer |
|---|---|
| Auricle | an irregularly shaped plate of elastic cartilage |
| Cerumen | ear wax, traps foreign bodies, bacteriostatic |
| Sebum | prevents the skin from drying out |
| Bacteriostatic | prevents bacteria from multiplying (in cerumen) |
| Tympanic membrane | separates external auditory meatus from the middle ear |
| 3 layers of tympanic membrane | Covered on both sides by epithelium. Outer layer thin, cutaneous layer consistent with skin of the EAM. Middle layer tough, fibrous connective tissue. |
| Function of External Ear | funnels sound through the ear canal to the tympanic membrane |
| As a result of the structure, the auricle and EAM... | amplify incoming acoustic pressure and plays the role of an acoustic antenna |
| Otoscopy | visual examination of the aurical, external auditory meatus and tympanic membrane |
| Microtia | congenital deformity of the external ear, varies in severity |
| Anotia | total absence of the auricle |
| Atresia | absence of the EAM |
| Cysts | non-cancerous, closed pockets of tissue that can be filled with fluid (pus). Result of infection, clogging of sebaceous glands or around foreign bodies. |
| Keloids | benign overgrowth of scar tissue that appear at the site of a skin injury. Dense, painful and pruritic (itchy) nodules. |
| Exostosis | surfer's ear, bone under skin develops lumps that grow into the EAM |
| Carcinoma | malignant tumors, looks like peeling scabs |
| EAM fracture | may cause the EAM to collapse, perhaps due to a broken jaw |
| Tympanosclerosis | membrane thickening resulting from chronic inflammation or trauma |
| Tympanic Membrane Perforation | direct trauma. May require tympanoplasty. |
| Otitis Externa | Swimmer's ear. Inflammation of the EAM. |
| Myringitis | infectious disorder resulting in painful blisters on the surface of the tympanic membrane |