Learning Objective: At the end of this session, the learner will be able to describe the anatomy of the nasal skeleton, including its bony and cartilaginous components, explain its role in forming the nasal cavity and septum, and recognize its clinical importance in nasal fractures.
The nasal skeleton is a structural framework composed of bone and cartilage, forming both the external nose and the internal nasal septum, which divides the two nasal cavities. It plays an essential role in maintaining airway patency, supporting the nasal passages, and shaping the nose.
Anatomical Structure
The nasal skeleton consists of three main tissue types:
- Bone
- Hyaline cartilage
- Fibro-fatty tissue
For clarity, it is divided into two parts:
- External Nasal Skeleton
- Internal Nasal Septum
External Nasal Skeleton
The external nasal skeleton extends from the nasal cavities onto the face.
- Superiorly, it is formed by the nasal bones and the frontal processes of the maxillae.
- Inferiorly, it is made up of hyaline cartilage, which gives the lower nose its shape and flexibility.
The key cartilaginous elements include:
- Lateral cartilages
- Major (greater) alar cartilages
- Minor (lesser) alar cartilages
- Cartilaginous septum
The lateral and major alar cartilages are the largest and determine the overall nasal contour. The minor alar cartilages vary in number (commonly three or four per side) and help maintain nostril shape.
Internal Nasal Septum
The nasal septum divides the nasal cavity into right and left halves. It has both bony and cartilaginous components.
Bony Part
- Paired bones: Nasal, Maxillary, Palatine
- Unpaired bones: Ethmoid, Vomer
Cartilaginous Part
- Septal cartilage (anterior portion)
- Greater alar cartilage (supports the nasal tip)
The ethmoid bone forms the superior and central part of the septum, while the vomer contributes to the posterior portion. The septal cartilage forms the flexible anterior part of the septum and connects with the external nose.
The roof of the nasal cavity is formed by the cribriform plate of the ethmoid bone, and the floor by the hard palate, comprising:
- Palatine process of the maxilla (anteriorly)
- Horizontal plate of the palatine bone (posteriorly)
Summary Table
| Region | Components | Function |
|---|---|---|
| External nasal skeleton | Nasal bones, maxillae, alar & lateral cartilages | Shapes and supports the external nose |
| Internal nasal septum | Ethmoid, vomer, septal cartilage | Divides the nasal cavity |
| Roof of the nasal cavity | Cribriform plate (ethmoid) | Passage for olfactory nerves |
| Floor of the nasal cavity | Hard palate | Separates the oral and nasal cavities |
Clinical Relevance
Nasal Fracture
Because the nasal skeleton is prominently positioned, it is prone to fracture, making it the most common facial bone injury.
- Cause: Blunt trauma (sports, falls, collisions).
- Most affected site: Junction between the nasal bones and upper lateral cartilages.
- Complications:
- Cosmetic deformity
- Septal hematoma or abscess
- Nasal obstruction
- Potential cartilage necrosis if untreated
Early diagnosis and proper alignment (closed reduction) are vital to restore both function and appearance.
