Outer Ear Anatomy

1 in to cm

2.54 cm

1 cm to mm

10 mm

10 mm to in

.394 in

2.52 cm to mm

25.4 mm

Peripheral auditory system

Outer, middle, and inner ear

What is the pinna primarily made of

Cartilage

Deep center portion of the pinna

Concha

Present in the skin covering the concha and the cartilaginous part of the ear canal

sebaceous glands

1. triangular fossa

2. anterior crus of the helix

3. tragus

4. concha

5. lobule

6. helix

7. posterior crus of the helix

8. scapha

9. cymba of concha

10. antihelix

11. antitragus

    other: intertragal notch, darwin’s tubercle, cavum of concha

Muscles of the pinna

extrinsic and intrinsic muscles

length of the EAM

25mm

diameter of EAM

6-8mm

T or F: skin in outer 1/3 EAM is 0.5 to 1mm thick

True (inside is 0.2mm)

Outer 1/3 of EAM

cartilaginous

Medial 1/3 of EAM

osseous

Most narrow part of the EAM

isthmus

Arnold’s reflex

stimulus of the vagus nerve that makes a person cough when touching ear canal

Nerves in EAM

Trigeminal (V), Facial (VII), and Vagus (X)

Extrinsic muscles

Anterior auricular muscle

Posterior auricular muscle

Superior auricular muscle

Intrinsic muscles

Helicus major and minor

Tragal

Anti-tragal

Auricular

Transverse

Purpose of muscles in ears

stabilization