The nasal bone is a paired, symmetrical bone of the facial skeleton, consisting of two small, oblong structures. Classified as part of the viscerocranium (the bones of the face), these bones form the underlying structure for the upper part of the nose, providing both shape and support.
Defining the Precise Location
The nasal bones are positioned side-by-side in the center of the upper face, situated between the eyes and above the upper jaw. They are located at the superior, or highest, part of the nose, collectively forming the bony vault known as the bridge of the nose.
The two bones meet along the midline of the face, forming the internasal suture. This central placement creates the prominent ridge of the nose. The nasal bones sit superior to the flexible nasal cartilages, which form the lower two-thirds and the tip of the nose.
The bony framework they create is the foundation of the upper third of the nose’s external structure. This placement in the midface means the nasal bones are easily palpable and visible under the skin. Their position makes them the thickest and most rigid part of the entire nose structure.
Shape and Structure
Each nasal bone is a small, roughly rectangular or quadrangular plate that varies in size and form between individuals. This variation contributes to the differences in nose appearance seen across the human population. The two bones are slightly thicker where they connect superiorly to the skull and become thinner toward the lower, inferior edge.
The external surface of the bone, facing outward, is generally convex (curved outward) from side to side. This outer surface is covered by small facial muscles, such as the Procerus and Nasalis, used for facial expressions. Conversely, the internal surface, facing the nasal cavity, is concave (curved inward) and features a vertical groove that accommodates a branch of the nasociliary nerve.
Bony Connections
The nasal bone has four borders that articulate with several surrounding facial and cranial bones. Superiorly, the nasal bone joins the frontal bone of the forehead, forming the frontonasal suture at the highest point of the nose bridge, a junction also known as the nasion.
Laterally, each nasal bone connects to the frontal process of the maxilla (the upper jaw bone), forming the nasomaxillary suture. Medially, the two nasal bones connect along the internasal suture. Inferiorly, the free lower border meets the upper lateral nasal cartilage, forming the transition point between the bony and cartilaginous parts of the nose.
Role and Importance
The primary function of the nasal bones is to provide a strong, stable framework for the nose and support the overlying soft tissues. They form the upper boundary and roof of the nasal cavity. This bony shield offers protection to the delicate nerves and blood vessels within the nasal structure.
The nasal bones also support the nasal septum, the internal partition that divides the nasal cavity for airflow. Due to their prominent and exposed position on the face, these bones are vulnerable to trauma and are among the most frequently fractured bones in the facial skeleton.