Structure of the Nose

Anatomy, Functions, and Clinical Significance

The human nose is a remarkably complex organ that serves as the primary passage for air, a sensory organ for smell, and an important part of the immune defense system. Its structure is carefully designed to support breathing, olfaction, and speech. Understanding the nose’s anatomy is essential for anyone interested in health, medicine, or physiology.

External Nose: The Visible Framework

The external nose is the part of the nose you see on the face. It consists of:

Nasal bones: Form the upper bridge of the nose.
Cartilaginous structures: Include lateral, septal, and alar cartilages that shape the tip and nostrils.
Nostrils (nares): Two openings that allow air entry.

Function:
The external nose guides airflow into the nasal cavity, supports facial structure, and provides an aesthetic appearance. Its shape also influences air resistance, which is important for effective respiration.

Internal Nose: The Nasal Cavity

The nasal cavity extends from the nostrils to the nasopharynx and is separated by the nasal septum into two symmetrical chambers.

Key Components:

Nasal Septum:
- Composed of bone (vomer and perpendicular plate of the ethmoid) and cartilage.
- Divides the nasal cavity and supports airflow regulation.
Mucous Membrane:
- Lines the nasal cavity.
- Contains cilia to move mucus and trapped particles toward the throat.
- Produces mucus to trap dust, allergens, and pathogens.
Vestibule:
- The front portion of the nasal cavity.
- Lined with hair (vibrissae) that filters large particles.

Nasal Conchae (Turbinates)

The turbinates are curved bony structures on the lateral walls of the nasal cavity:

Inferior turbinate
Middle turbinate
Superior turbinate

Functions:

Increase surface area for air contact.
Create turbulence to warm, humidify, and filter air.
Enhance the effectiveness of the olfactory region.

Olfactory Region

Located in the upper part of the nasal cavity, this area contains olfactory epithelium with:

Olfactory receptor neurons: Detect smell.
Supporting cells: Maintain structure and function.
Basal cells: Regenerate olfactory neurons.

Function:
The olfactory region allows humans to detect and distinguish odors, linking smell to memory and emotion through the olfactory nerve.

Paranasal Sinuses

The paranasal sinuses are air-filled cavities surrounding the nasal cavity:

Frontal sinuses
Maxillary sinuses
Ethmoid sinuses
Sphenoid sinuses

Functions:

Reduce skull weight
Produce mucus for trapping pathogens
Act as resonating chambers for speech

Blood Supply and Innervation

Blood supply: From branches of the sphenopalatine, facial, and ophthalmic arteries.
Nerves: Trigeminal nerve for sensation; olfactory nerve for smell.
The rich vascular network helps warm inhaled air and can contribute to nosebleeds (epistaxis).

Functional Significance of Nasal Structure

The nose’s structure enables multiple essential functions:

Air filtration: Traps dust, pollen, and pathogens.
Air conditioning: Warms and humidifies inhaled air.
Olfaction: Smell detection via olfactory region.
Resonance in speech: Nasal cavity acts as a sound chamber.
Immune defense: Mucosa and cilia remove harmful particles.

Clinical Relevance

Understanding nasal anatomy is critical for diagnosing and treating:

Deviated septum – may affect airflow and breathing.
Nasal polyps – obstruct normal nasal function.
Chronic sinusitis – inflammation of sinuses affecting airflow.
Anosmia – loss of smell due to olfactory region damage.

Conclusion

The structure of the nose is a masterclass in biological engineering. Its external and internal frameworks, combined with specialized regions like turbinates and olfactory epithelium, allow it to perform vital functions ranging from respiration and smell to immunity and speech resonance. Maintaining nasal health is crucial for overall respiratory efficiency and sensory well-being.

OTHER SOURCES

The external nose is visible and is pyramidal in shape, with the root located in the upper region and the base located in the lower region. The variance in shape depends on the shape of the ethmoid bone which is an anterior cranial bone located between the eyes. The internal nose is divided into the left and right nasal cavities by the nasal septum. The internal nose also consists of the skin-lined region known as the vestibule and the mucosa-lined region known as the nasal cavity proper.

The nasal framework

The nasal or piriform aperture is situated on the bony skull and represents a bony outline of the nasal cavity, which is the beginning of the respiratory tract. The nasal pyramid is located here with each side consisting of the frontal process of the maxilla and medial to the nasal bone which is linked to the frontal bone.

The nasal cartilage

The front of the nose consists of connective tissue with embedded small pieces of cartilage. This includes the nasal septum and the nasal tip cartilage (lesser alar cartilage and lateral greater alar cartilage). Whatever impression the nose makes as an aesthetically significant element of the face – high, broad, or even crooked – is largely determined by these small cartilages and the cartilaginous portions of the nasal septum. Frequently, the bony portion of the nose is affected by midfacial fractures (e.g., a nasal bone fracture).

A common cause of nasal fractures is blunt trauma. Manual alignment through the application of strong thumb pressure with anesthesia followed by repair may be necessary to prevent lasting misalignments. Injuries that lead to functional impairments may be corrected through nasal surgery or rhinoplasty.

Internal nose

The inner part of the nose is formed by the main nasal cavity which includes the nasal concha, nasal passages (nasal meatus), and paranasal sinus. The nasal septum comprises bone and cartilage in the nose and separates the nasal cavity into two fossae, which are continuations of the nostrils and jointly form their medial border. The nasal septum consists of four structures:

Clinically, deviations of the nasal septum occur quite frequently. These deviations may be present at birth or may result from an accident. A deviated nasal septum can lead to nasal congestion and breathing difficulties which may require surgical correction. Structure of the Nose .

Structure of the Nose Video :

DIAGRAM OF THE HUMAN NOSE

Structure of the Nose