The frontal bone forms the forehead and the upper part of the eye sockets, protecting the frontal lobe of the brain.
The frontal bone is a single, flat cranial bone located in the anterior part of the skull. It forms the forehead, the roofs of the orbits (eye sockets), and contributes to the anterior cranial fossa. As a key part of the neurocranium, the frontal bone protects the frontal lobes of the brain and plays an important role in facial structure and sinus drainage. It is one of the most visible and anatomically significant bones of the skull.
The frontal bone is composed of dense cortical bone with a spongy diploë layer in between. It is broadly divided into two main parts:
Internally, the frontal bone contains two air-filled cavities called the frontal sinuses, which communicate with the nasal cavity and contribute to voice resonance and mucus drainage.
The frontal bone is located at the front of the skull. It lies superior to the nasal bones and maxilla, and anterior to the parietal bones. It articulates with multiple bones, forming joints at the front of the face, sides of the cranium, and the skull base. It also forms part of the orbital roof and contributes to the anterior cranial base that supports the frontal lobes of the brain.
The frontal bone articulates with 12 bones:
The frontal bone develops from two primary centers of ossification — one in each half of the developing bone. These centers fuse at the midline during early childhood.
Inflammation of the frontal sinus can result from infections and may cause forehead pain and pressure. In severe cases, the infection can spread to adjacent structures, including the brain (e.g., frontal lobe abscess).
Frontal bone fractures commonly occur in high-impact injuries. They may involve the anterior table (outer surface) or posterior table (near the brain). Posterior table fractures are more dangerous due to proximity to the frontal lobe and meninges, potentially leading to cerebrospinal fluid (CSF) leakage.
In some individuals, the metopic suture persists into adulthood. While it is a normal variant, it may be mistaken for a fracture in radiographic imaging if not recognized properly.
Neurosurgical procedures may involve craniotomies that access the frontal lobe by removing a section of the frontal bone. Surgeons must consider the position of the frontal sinuses and avoid damaging the orbital roof or dura mater.
Frontal sinus patterns are unique to individuals and are sometimes used in forensic cases for identification purposes via radiographs or CT imaging.
On X-ray and CT scans, the frontal bone appears as a dense, curved structure forming the anterior skull. The frontal sinuses are visible as radiolucent (dark) areas within the squamous part. Persistent metopic sutures or fractures must be carefully differentiated in imaging studies.