The frontal bone is one of the bones of the skull. When people are born, the bones of the skull are separated by a series of soft sutures that give the skull room to grow. Over time, the sutures ossify, hardening and creating a solid skull. The different parts of the skull are referred to as individual bones whether they are still distinguishable as clearly separate bones or not, and each bone of the skull has a number of distinct anatomical structures that are also named.
In the case of the frontal bone, the bone comprises part of the cranial vault, the area of the skull designed to hold and protect the brain. The bones in the cranial vault must be durable and their undersides are lined with a number of structures designed to allow for the drainage of cerebrospinal fluid while accommodating the structures of the brain itself, as well as nerves and blood vessels. The frontal bone corresponds to the front lobes of the brain, located near the forehead.
This bone covers the forehead down to the eyes and includes a horizontal portion that makes up the roof of the eye sockets as well as the nasal cavities. The frontal sinuses are located just above the orbits, the depressions for the eyes, inside the frontal bone. In order to accommodate bloodflow to the eyes, small notches or openings known as orbital foramina are located near the eye sockets. The bone articulates with other bones in the skull like the nasal, ethmoid, parietal, zygomatic, and maxillary bones.
Fractures of the frontal bone can be caused by blows to the head, as well as falls on hard surfaces or against sharp and hard objects. If this bone is fractured, a medical emergency can occur, as brain damage to the frontal lobes is associated with frontal bone fractures. In addition, fracturing the bone may disrupt the orbits, causing damage to the eyes or to the structures deep inside the nose. Usually a physical examination and X-ray can be used to spot a frontal bone fracture and there are treatments available.
Some variations in the shape and size of the frontal bone are normal. Some genetic conditions are associated with variations in skull shape and size and people can also be born with prematurely fused cranial sutures that cause the shape of the skull to become distorted. Having an unusually small or large forehead does not necessarily provide any indications about someone's cognitive abilities or intelligence.