Calvaria

The calvaria refers to the uppermost part of the skull, which acts as a protective covering for the brain by forming the roof of the cranial cavity. It consists of several bones, namely the frontal bone, parietal bones, temporal bones, and occipital bone. Within the calvaria, different sutures are present to connect these bones. For instance, the coronal suture runs sideways, connecting the frontal bone in the front to the two parietal bones. The two parietal bones articulate with each other through the midline sagittal suture, which lies in an antero-posterior direction. At the posterior end, the parietal bones join with the occipital bone through the lambdoid suture, running sideways.

The meeting point of the coronal and sagittal sutures is known as bregma. While, the point where the lambdoid and midline sagittal sutures intersect is known as lambda. Both these bony landmarks represent the points where the anterior and posterior fontanelle were situated in infants after birth.

On either side, each parietal bone articulates with the squamous temporal bone below through the squamous suture, and with the mastoid process through the parietomastoid suture. Further behind, the occipital bone connects with the mastoid process through the occipitomastoid suture. The anterior end of squamous suture is called pterion, which marks the junction of four bones, namely the frontal, parietal, sphenoid, and temporal. While moving backwards on the lateral side, the bony junction between the parietal, occipital and mastoid bones is called the asterion. The latter also marks the junction of lambdoid, parietomastoid, and occipitomastoid sutures.