The normal structure of the nose consists of external and internal components that work together for breathing, smell, and filtering air.
External Nose Structure
- Skin: The outer covering, protecting the underlying structures.
- Nasal Bones: These bones form the bridge of the nose.
- Cartilage: Primarily made up of cartilage including:
- Septal cartilage: Forms part of the nasal septum.
- Lateral cartilages: Located on either side of the septum.
- Alar cartilages: Form the shape of the nostrils.
- Nostrils (Nares): The external openings of the nose.
Internal Nose Structure (Nasal Cavity)
The nasal cavity is the space inside the nose, divided into two passages by the nasal septum.
- Nasal Septum: A wall made of bone and cartilage that divides the nasal cavity into right and left sides. Ideally, the septum is straight, allowing equal airflow through both nasal passages.
- Nasal Conchae (Turbinates): Bony shelves covered with mucous membrane that project into the nasal cavity. There are typically three sets:
- Superior conchae: Located highest in the nasal cavity.
- Middle conchae: Located in the middle of the nasal cavity.
- Inferior conchae: Located lowest in the nasal cavity.
The conchae increase the surface area of the nasal cavity, warming and humidifying the air as it passes through.
- Mucous Membrane: A lining covering the nasal cavity, sinuses, and throat. This membrane produces mucus, which traps dust, pollen, and other particles, preventing them from entering the lungs. The mucus also helps to humidify the air.
- Cilia: Tiny, hair-like structures on the surface of the mucous membrane that sweep mucus and trapped particles towards the throat to be swallowed or expelled.
- Sinuses: Air-filled spaces in the bones of the face that connect to the nasal cavity. They help to lighten the skull, humidify the air, and may play a role in voice resonance. The four pairs of sinuses are:
- Maxillary sinuses: Located in the cheekbones.
- Frontal sinuses: Located in the forehead.
- Ethmoid sinuses: Located between the eyes.
- Sphenoid sinuses: Located behind the ethmoid sinuses.
- Olfactory Region: Located at the top of the nasal cavity, containing specialized cells responsible for the sense of smell.
In summary, the nose's structure, comprising bone, cartilage, mucous membranes, and sinuses, facilitates breathing, air filtration, and the sense of smell.
