Calvaria (skull)

Upper part of the skull

Calvaria (skull)

The calvaria or skullcap is the upper part of the cranium that encloses and protects the brain. It is composed of several bones that are fused together in adults, forming a rigid structure. The calvaria is an essential component of the human skull, providing both protection and structural support.

Anatomy

The calvaria is formed by the superior portions of the frontal bone, parietal bones, and the occipital bone. These bones are connected by fibrous joints known as sutures. The major sutures of the calvaria include the coronal suture, sagittal suture, and lambdoid suture.

Functional architecture of cranium

Bones

• Frontal bone: This bone forms the forehead and the upper part of the eye sockets. It articulates with the parietal bones at the coronal suture.
• Parietal bones: These are two large bones that form the sides and roof of the cranium. They meet at the sagittal suture.
• Occipital bone: Located at the back of the skull, it forms the base of the cranium and articulates with the parietal bones at the lambdoid suture.

Sutures

• Coronal suture: The joint between the frontal bone and the parietal bones.
• Sagittal suture: The joint between the two parietal bones.
• Lambdoid suture: The joint between the parietal bones and the occipital bone.

Development

The calvaria develops through a process called intramembranous ossification, where bone tissue forms directly from mesenchymal tissue. During infancy, the bones of the calvaria are not fully fused, allowing for growth of the brain and skull. The gaps between the bones are known as fontanelles, which eventually close as the child grows.

Function

The primary function of the calvaria is to protect the brain from mechanical injury. It also provides attachment points for muscles and supports the structure of the face. The calvaria's shape and thickness can vary among individuals, influenced by genetic and environmental factors.

Base of the skull

Clinical significance

Injuries to the calvaria, such as fractures, can occur due to trauma. These injuries may require medical intervention to prevent damage to the brain. Conditions such as craniosynostosis, where the sutures close prematurely, can affect the shape of the skull and require surgical correction.

Related pages

• Cranium
• Suture (joint)
• Fontanelle
• Craniosynostosis

Sagittal section of skull