Lecture on Ear Anatomy and Pathologies

Introduction

• Speaker: Jade, medical student from Leicester
• Topics Covered: Anatomy of the ear and related pathologies

Anatomy of the Ear

Parts of the Ear

1. External Ear

   • Components:
     • Auricle (Pinna): Visible part of the ear, funnel-shaped.
     • External Auditory Meatus: S-shaped canal leading to the tympanic membrane.
   • Function: Captures and directs sound waves.
   • Structure: Cartilaginous with a fleshy lobule.

2. Middle Ear

   • Role: Transmits and amplifies vibrations.
   • Components:
     • Ossicles: Malleus, Incus, and Stapes connect the tympanic membrane to the oval window.
     • Muscles: Tensor Tympani and Stapedius restrict movement in response to loud noises.
   • Surrounding Structures:
     • Superiorly: Brain (risk of infections like meningitis if cranial floor fractures occur).
     • Inferiorly: Internal Jugular Vein.
     • Laterally: Tympanic Membrane.
     • Medially: Facial Nerve (can be affected in otitis media).
     • Anteriorly: Eustachian Tube connects to nasopharynx; equalizes pressure.

3. Inner Ear

   • Role: Converts vibrations into nerve signals; helps with balance.
   • Components:
     • **Vestibular Apparatus and Cochlea.
     • Cochlea:** Converts vibrations to action potentials, which are sent to the brain via Cranial Nerve VIII.
     • Vestibular Apparatus: Composed of semicircular ducts, saccule, and utricle; maintains balance.

Pathologies of the Ear

Otitis Externa

• Causes: Bacterial (Pseudomonas, Staphylococcus) or Fungal (Aspergillus, Candida) infection.
• Symptoms: Otalgia, otorrhea.
• Management: Micro suction, analgesia, topical antibiotics or corticosteroids.
• Complications: Malignant otitis externa in diabetic/immunocompromised patients.

Otitis Media

• Causes: Pathogens like Influenza virus, Haemophilus influenzae.
• Symptoms: Otalgia, fever, conductive hearing loss.
• Management: Conservative, delayed antibiotics, analgesia.
• Complications: Perforated eardrum, mastoiditis, sepsis, Bell's palsy, meningitis.

Otitis Media with Effusion (Glue Ear)

• Common in: Children due to horizontal Eustachian tube.
• Symptoms: Conductive hearing loss, poor speech development.
• Management: Usually self-limiting, advice on hearing loss management, grommet insertion for recurrent cases.

Cholesteatoma

• Characteristics: Non-cancerous growth of squamous epithelium.
• Symptoms: Conductive hearing loss, foul-smelling discharge.
• Management: Surgical emergency.

Otosclerosis

• Characteristics: Fusion of the stapes to the oval window.
• Symptoms: Conductive hearing loss, tinnitus.
• Management: Stapedectomy or hearing aids.

Vertigo

• Types and Causes:
  • Benign Paroxysmal Positional Vertigo (BPPV): Movement of crystals in semicircular canals.
  • Vestibular Neuritis: Inflammation of the vestibular nerve.
  • Labyrinthitis: Infection causing vertigo and hearing loss.
• Management: Epley maneuver for BPPV, conservative management for other causes.

Hearing Loss

• Types:
  • Sensorineural: Inner ear or nerve problems (e.g., acoustic neuroma).
  • Conductive: Issues in sound transmission (e.g., ear wax, otitis media).
• Tests: Weber and Rinne's tuning fork tests.

Acoustic Neuroma

• Characteristics: Benign mass of Schwann cells.
• Symptoms: Unilateral sensorineural hearing loss, vertigo.
• Management: MRI, conservative or surgical treatments.

Meniere's Disease

• Characteristics: Build-up of endolymph.
• Symptoms: Episodes of hearing loss, vertigo, tinnitus.
• Management: Prochlorperazine for attacks, beta-histine for prevention.

Conclusion

• Importance of understanding ear anatomy and pathologies for diagnosis and treatment.