1. Anatomy and physiology of the external ear. Non-inflammatory diseases and inflammatory diseases. Otomycosis.

Question 1

Describe the Anatomy of the External Ear

Answer 1

• Auricle AND External Auditory Canal (EAC) = Anatomical + Functional Unit
• Auricle’s shape is determined by ELASTIC CARTILAGE
• On the Lateral Surface, skin has NO sub.cut tissue BUT is ATTACHED to the CARTILAGE
• Skin Inflammation MAY AFFECT the PERICHONDRIUM, leading to permanent changes
• ISTHMUS is the NARROWEST Part

Question 2

What Contigious Structures is the External Auditory Canal (EAC) connected to?

Answer 2

• Tympanic Membrane
• Mastoid
• Glenoid Fossa
• Cranial Fossa
• Infratemporal Fossa

Question 3

Describe the Innervation of the External Ear

Answer 3

1) GREATER Auricular Nerve, FROM the CERVICAL Plexus

2) Auriculo TEMPORAL, FROM the TRIGEMINAL Nerve (C3)

3) SENSORY Branches of C7, FROM the Posterior Auricular Nerve

4) AURICULAR Branch of C10 (ARNOLDs Nerve)

Question 4

Describe the Arterial Supply of the External Ear

Answer 4

• Superficial TEMPORAL Artery
• Posterior AURICULAR Artery

Question 5

Describe the Venous Drainage of the External Ear

Answer 5

1) Superior TEMPORAL Vein to RETROMANDIBULAR to COMMON FACIAL to INTERNAL JUGULAR Vein

2) Posterior AURICULAR Vein to EXTERNAL JUGULAR Vein

Question 6

Describe the Lymphatics of the External Ear

Answer 6

• Pre-Auricular AND Parotid / Superficial CERVICAL LN
• Posterior AURICULAR LN
• Deep CERVICAL LN

Question 7

Describe the PHYSIOLOGY of the External Ear - AABP

Answer 7

1) Antenna = conveys sound of MIDDLE EAR

2) Amplification = resonance for 2 - 4 KHz

3) Binaural Hearing = Direction / Orientation

4) Protection = Wax + Isthmus

Question 8

What are the NON-INFLAMMATORY Diseases of the External Ear?

Answer 8

1) Cerumen
2) Foreign Bodies
3) Injuries & Physical Damage

Question 9

What is CERUMEN? (Non-Inflam.)

Answer 9

• AKA Earwax!
• Produced by CERUMEN + SEBACEOUS GLANDS of Skin of EAR CANAL
• DUE to
  a. DISTURBANCES in Normal Self-Cleaning = With COTTON BUD that can DISPLACE CERUMEN towards TYMPANIC MEMBRANE

b. EXCESSIVE Secretions = made up of = CERUMEN GLANDS mixed with SEBUM, EXFOLIATIVE DEBRIS

• Symptoms = Pressure sensation in ear WITH CONCOMITANT Hearing Loss / Vertigo / Tinnitus
• Diagnosis = OTOSCOPY reveals OBSTRUCTION (Yellow/Brown - Black)
• Complications = OTITIS EXTERNA (Rare!)
• Treatment = REMOVAL with HOOK CURETTE / AURAL Irrigation

Question 10

What are the FOREIGN BODIES? (Non-Inflam.)

Answer 10

• Putting Toys into Ear (CHILDREN)
• Ear Plugs / Insects (ADULTS)
• Diagnosis = Done via HISTORY and OTOSCOPY
• Complications = MIDDLE + INNER EAR Damage / Prolonged RETENTION of foreign bodies, causing SECONDARY OTITIS EXTERNA
• Treatment = Foreign Bodies are REMOVED with EXTRACTION HOOK

Question 11

What are the INJURIES / PHYSICAL DAMAGE? (Non-Inflam.)

Answer 11

• AURICULAR SEROMA / HEMATOMA = Collection of Blood AND Serous Fluid BTW PERICHONDRIUM and AURICULAR CARTILAGE
• DUE to BLUNT TRAUMA from CONTACT Sports
• Symptoms = Painful Trauma
• Diagnosis = (PHYSICAL EXAM) Swollen, Fluctuated Skin OVER the LATERAL AURICULAR Cartilage
• Complications = SECONDARY INFX, due to NEEDLE ASPIRATION (hematoma), causing PERICHONDRITIS
• Treatment = SURGICAL EVACUATION (hematoma) / RE-ATTACHMENT of PERICHONDRIUM (Cartilage)

Question 12

What are the Inflammatory Diseases of the External Ear?

Answer 12

1) Eczema / Dermatitis of Auricle
2) Herpes Zoster Oticus
3) Diffuse Otitis Externa / Eczema of Ear Canal

Question 13

What is Eczema / Dermatitis of Auricle? (Inflam.)

Answer 13

• Inflammatory Condition of the Auricle, CONFINED TO Dermis
• Caused by Jewellery / Soaps / Hearing Aids
• Symptoms = Itching, Burning / Pain / Erythematosus / Dry, Scaly / Moist Skin
• Diagnosis = Allergies suspected!
• Complications = Cracked Skin, increasing risk of Bacterial Infections (Pyoderma, Perichondritis)
• Treatment = Skins Lesions are based on Dermatologic Principles (ANTIBIOTICS)

Question 14

What is Herpes Zoster Oticus? (Inflam.)

Answer 14

• AKA Ramsay Hunt Syndrome
• DUE to REACTIVATION of Virus in GANGLION CELLS, involving CN7, CN8
• Symptoms = Ear Pain / Erupted Vesicle / Hearing Loss
• Diagnosis = Typical Clustered Vesicles / Lymphadenitis of Cervical LN
• Treatment = Systemic Therapy with ACYCLOVIR and CORTICOSTEROIDS (Facial Nerve Palsy)

Question 15

What is Diffuse Otitis Externa / Eczema of Ear Canal? (Inflam.)

Answer 15

• Inflammation of the External Ear Canal
• Symptoms = Itching / Pain / Crusting / Purulent Aural Discharge
• Diagnosis = Inspection
• Treatment = Cleanse Area THEN antiseptic / antibiotic Drops (GENTAMICIN)

Question 16

What is OTOMYCOSIS?

Answer 16

• FUNGAL Infection of MIDDLE EAR CANAL
• Most Common during the SUMMER
• Symptoms = SEVERE Itching / Fullness
• Diagnosis = OTOSCOPY reveals Yellow-White-Black Fungus, LINING THE Swollen Erythematosus Skin of Ear Canal
• BONY PART is affected the MOST!
• Treatment = Ear Canal cleaned thoroughly // SOFTEN the Uppermost Epithelial Layer with SALICYLATE (enhance anti-fungal action) // LOCAL ANTIMYCOTICS