13. Nose

Contents of the Course

  • Anatomy and Physiology of Nose and Paranasal Sinuses

  • Disorders of the External Nose and Nasal Vestibule

  • Nasal Septum Disorders

  • Miscellaneous Disorders of Nasal Cavity

  • Allergic Rhinitis

  • Rhino sinusitis

Anatomy of Nose and Paranasal Sinuses

External Nose

  • Shape: Pyramidal with the root directed upwards and the base downwards.

  • Framework: Osteocartilaginous framework covered by muscles and skin.

    • Upper 1/3: Bony structure

    • Lower 2/3: Cartilaginous

  • variations in skin texture:

    • Upper 1/3: Loose skin

    • Lower 2/3: Thick, adherent to cartilage, rich in sebaceous glands.

  • Surface anatomy of the nose

    The External Nose
The Nasal Cartilage lateral wall of the nose

Septum anatomy

ANATOMY OF NASAL SEPTUM

Nasal Musculature

  • Framework covered by 7 muscles controlling facial animation and respiration.

    • Muscle Groups: Depressors, elevators, compressors, and dilators.

Internal Nose/Nasal Cavity

  • Division: Right and left nasal cavities separated by nasal septum.

  • Each cavity communicates with the exterior via nostrils and with the nasopharynx through choana.

  • Nasal cavity structure:

    • Skin-lined vestibule

    • Mucosa-lined proper nasal cavity consisting of:

      • Olfactory region

      • Respiratory region

  • Failure of canalization: Results in choanal atresia.

Lining Membrane of Internal Nose

  1. Vestibule:

    • Lined with skin, containing sebaceous glands and hair follicles (vibrissae).

  2. Olfactory Region:

    • Upper 1/3 covered by olfactory epithelium; mucous membrane lighter in color.

  3. Respiratory Region:

    • Lined by pseudostratified ciliated columnar epithelium with goblet cells.

Nasal Cavity Proper

  • Each nasal cavity comprises lateral wall, medial wall, roof, and floor.

  • Medial wall includes the nasal septum, divided into:

    1. Columellar septum

    2. Membranous septum

    3. Septum proper (osteocartilaginous framework).

Nasal Cavity – Earth's Lab

Membranes of internal nose

  • Vestibule

    • The vestibule is the initial part of the nasal cavity, located just inside the nostrils, and is lined with skin containing sebaceous and sweat glands and hair follicles.

  • Respiratory region

Functions of Nasal and Paranasal Structures

  • Respiration: Primary function.

  • Air-conditioning: Involves filtration, temperature control, and humidification of inspired air.

  • Protection: Safeguards lower airway.

  • Vocal resonance: Affects sound production.

  • Nasal reflex functions: Enhances responses to stimuli.

  • Olfaction: Essential for the sense of smell.

Disorders of Nose

General Disorders

  1. Cellulitis: Infection leading to red, swollen, tender nose; requires antibiotics.

  2. Nasal Deformities: Include saddle nose, hump nose, and deviations; may be due to trauma or congenital factors.

  3. Tumours: Include both benign (e.g., rhinophyma) and malignant forms (e.g., basal cell carcinoma).

Specific Conditions of Interest

  • Rhinophyma: Hypertrophy of sebaceous glands affecting the lower 1/3.

  • Nasal Polyp: Non-neoplastic mass; associated with chronic inflammation and asthma.

  • Rhinosinusitis: Involves inflammation of sinus mucosa; can be acute or chronic.

  • Allergic Rhinitis: IgE mediated condition with characteristic symptoms; treated with avoidance, medications, and possibly immunotherapy.

Postoperative Complications

  • Complications post-surgery may include:

    • Bleeding, septal hematoma, perforation, saddle nose deformity, and cerebrospinal fluid rhinorrhoea.

Conclusion

  • Understanding the structure and function of the nose and paranasal sinuses is crucial for diagnosing and managing various ENT disorders.