The nasal septum is a central anatomical structure within the human nose, serving as a partition that divides the nasal cavity into two distinct passages. It extends from the nostrils backward to the nasopharynx, creating the medial wall for each side of the nasal cavity. This structure is composed of both bony and cartilaginous elements.
Key Bony Components
The posterior and superior portions of the nasal septum are primarily formed by two bones. The vomer, a thin, unpaired facial bone, constitutes the posteroinferior part of the nasal septum. The vomer articulates with several bones, including the sphenoid, ethmoid, maxilla, and palatine bones, providing a foundational base for the septum.
Positioned above and anterior to the vomer is the perpendicular plate of the ethmoid bone, a thin, flattened bone. This plate contributes to the superoposterior part of the nasal septum. The perpendicular plate provides rigidity to the upper and back portions of the septum, and its lower edge meets the vomer bone.
Additional Bony Contributions
While the vomer and the perpendicular plate of the ethmoid bone form the main bony framework of the septum, other bones offer additional support. The maxilla, specifically its nasal crest, contributes to the inferior aspect of the nasal septum.
Similarly, the palatine bones, located at the back of the nasal cavity, also contribute to the base of the septum. Their horizontal plates join with the maxillae to form the posterior part of the hard palate, providing a foundational support for the nasal septum. These contributions from the maxilla and palatine bones are essential for anchoring the more central septal structures.
Cartilaginous Framework
Beyond its bony components, the nasal septum also includes a significant cartilaginous part, which provides flexibility and contributes to the external shape of the nose. This is primarily the quadrangular cartilage, also known as the septal cartilage. This flexible, hyaline cartilage forms the anterior and inferior parts of the nasal septum, extending forward to the tip of the nose.
The quadrangular cartilage is somewhat quadrilateral in shape and is thicker at its edges than in its center. It articulates with the posterior margin of the perpendicular plate of the ethmoid bone and the inferior margin of the vomer and palatine processes of the maxillae. This cartilaginous section allows the nose to maintain its shape while also possessing a degree of elasticity.
Overall Structure and Purpose
The complete nasal septum is an integrated structure, formed by the precise articulation of its bony and cartilaginous components. The rigid posterior bony elements, including the vomer and the perpendicular plate of the ethmoid bone, provide stability, while the anterior cartilaginous portion allows for necessary flexibility. This combined architecture ensures the septum’s integrity and function.
The nasal septum’s primary purpose is to divide the nasal cavity into two distinct passages, which is fundamental for directing airflow. This separation allows for the efficient warming, humidifying, and filtering of inhaled air before it reaches the lungs. The septum also offers structural support for the external nose, helping to maintain its shape and patency.