Lateral aspect of cranium

The side view of the skull, known as the lateral aspect of cranium or norma lateralis, shows how the skull appears from the side. In this view, you can see various bones, including those from the neurocranium such as the frontal, parietal, sphenoid (greater wing), temporal, and occipital bones. Bones from the facial skeleton are also visible in this side view, including the nasal, maxilla, zygomatic, and mandible.

Some important sutures of the cranium that can be seen in the lateral view are the coronal and lambdoid sutures, which run from side to side. Towards the back, the lambdoid suture splits further into the occipitomastoid and parietomastoid sutures, at a point called the asterion. The squamous suture represents the connection between the squamous part of the temporal bone and the parietal bone.

The lateral aspect of the cranium is characterized by a shallow region called the temporal fossa, which is bounded by faint bony ridges known as the temporal lines on the front and top. Below, the lower boundary of the temporal fossa is marked by a bony bridge between the temporal and zygomatic bones called the zygomatic arch. Below the temporal fossa, there is another region called the infratemporal fossa.

Within the floor of the temporal fossa, there is an important muscle called the temporalis muscle, which assists in chewing and jaw movements. Beneath the muscle, there is a bony floor formed by four cranial bones: the frontal, parietal, squamous part of the temporal, and greater wing of the sphenoid bones. The point where all four bones meet is known as the pterion. This area is particularly prone to fractures that could lead to the rupture of the middle meningeal arteries underneath, potentially causing epidural hemorrhages.

The infratemporal fossa is hidden from the outside by the ramus of the mandible. It contains several important structures, including the pterygoid muscles of mastication, maxillary artery, and mandibular nerve and its branches, and the pterygoid plexus of veins.

Additional notable features in the lateral aspect of cranium include the external acoustic meatus (the opening of the external ear) and the bony mastoid process located directly behind the ear.