Frontal bone

The frontal bone is a single bone in an adult human skull. It plays a key role in shaping the upper-anterior part of the skull. It is shaped like a shell and can be divided into two sections: The first, known as the squamous part, is vertical and forms the forehead. The second, called the orbital part, is horizontal and creates a roof over the eye sockets and nasal cavities.

During the embryonic stage, it is separated into two parts by a midline suture known as the metopian suture, which usually merges later.

The frontal bone connects with various other skull bones. For example, when viewed from the front, it connects anteromedially with the nasal bone and laterally with the zygomatic bone on both sides. These medial and lateral connections of the frontal bone help to form the inner and outer edges of both orbital sockets.

Above each eye socket, the frontal bone stretches back from the superior orbital rim, forming what is known as the orbital part. This portion lies flat and forms the roof of the right and left eye sockets. This orbital roof connects to a few other bones along the medial wall of each eye socket, such as the lacrimal, ethmoid, and sphenoid bones. It also connects with bones along the outer or lateral wall of the eye socket, including the zygomatic bone and the greater wing of the sphenoid bone.

Inside the cranial cavity, the frontal bone connects to the ethmoid bone (cribriform plate) at the middle and the lesser wing of sphenoid bone at the back.