Anatomy
The cranium is the bony skull that surrounds
and protects the brain. It is composed of
eight bones: the ethmoid, frontal, occipital,
sphenoid, and two pairs of parietal and
temporal bones (Figure 1). The occipital,
temporal, parietal and frontal bones form
what may be thought of as the head rather
than the face. The nasal bone, maxillary and
zygomatic bones, and the mandible are the
major bony structures in the facial part of the
skull. The ethmoid and lacrimal bones are
smaller structures forming parts of the bony
orbits, and the sphenoid bone is a small bone
on each lateral aspect of the skull. The
occipital and frontal bones of the skull are
relatively strong and durable in comparison to
the parietal and temporal bones and are
therefore less likely to fracture.
An infant’s skull differs to that of an adult
in that it is much larger in relation to the face.
Beneath the skull there are three layers of
meninges – the dura mater, arachnoid mater
and pia mater (Figure 2). Arterial blood is
provided by the meningeal arteries and their
sub-divisions. The major arterial vessels
traverse the areas underlying the parietal and
temporal bones (Crimando 2012).