Structures of the Outer Ear - External Auditory Meatus Flashcards
1
Q
What is another name for the external auditory meatus?
A
- Ear canal
2
Q
What are three functions of the external auditory meatus?
A
- Protects the middle ear
- Transmits sound to the middle ear
- Resonating cavity: increases the amplitude of high-frequency sounds
3
Q
Location and details for the Cartilaginous meatus
A
- Cartilaginous portion of the ear canal
- Lateral 1/3 to 1/2 of the ear canal
- Lined with cilia and glands that secrete oil and cerumen (ear wax) to protect the ear canal and tympanic membrane
4
Q
Location details for the Osseous meatus
A
- Bony portion
- Medial 1/2 to 1/3 (text book says 2/3) of ear canal
- External auditory meatus of the temporal bone
5
Q
What/where is the isthmus?
A
- S-shaped constriction of the ear canal
- Marks the junction of the cartilaginous framework with the bony framework
- Can be straightened out by gently pulling the auricle superiorly and posteriorly for otoscopy
6
Q
What is Cerumen?
A
- Waxy, water-resistant substance
- Protects the ear canal from drying out
- Bitter, noxious, and sticky quality prevents the invasion of insects and other foreign bodies
- Has some antifungal and antibacterial qualities
7
Q
Label the Diagram
A
