The frontal bone is a single bone in the human skull that forms the forehead. It plays a crucial role in protecting the brain and contributing to the overall structure of the face.
Anatomy and Location
The frontal bone is situated at the anterior (front) and superior (upper) part of the cranium. It articulates (connects) with several other bones of the skull, including:
- Parietal bones (at the coronal suture)
- Sphenoid bone
- Ethmoid bone
- Zygomatic bones
- Nasal bones
- Lacrimal bones
- Maxillae
Development
In infants and young children, the frontal bone is actually two separate bones, divided by the metopic (or frontal) suture. This suture typically fuses between the ages of three and nine months, forming a single frontal bone. The persistence of the metopic suture into adulthood is rare, occurring in approximately 1-9% of individuals.
Key Features
The frontal bone contains several notable features:
- Squamous part: The largest portion, forming the forehead.
- Orbital part: Forms the superior (upper) part of the eye sockets (orbits).
- Superciliary arches: Bony ridges above the eye sockets, located just under the eyebrows.
- Glabella: The smooth area between the superciliary arches, just above the nose.
- Frontal sinuses: Air-filled cavities within the bone, which contribute to resonance of the voice and lighten the skull.
Function
The frontal bone serves several important functions:
- Protection: Protects the frontal lobe of the brain from injury.
- Support: Provides structural support for the face.
- Muscle attachment: Serves as an attachment point for muscles of facial expression.
- Sinus function: The frontal sinuses contribute to humidifying and filtering inspired air.
