Cranial and facial bones: Dental assisting

The cranial and facial bones form the framework of the head and face. Together, they support many important structures, including teeth, muscles, nerves, and blood vessels. Identifying specific anatomical landmarks of the cranial and facial bones is critical to many dental procedures, radiographic imaging, and accurate documentation. As a dental assistant, understanding this anatomy is essential to providing safe and effective patient care.

Let’s begin by reviewing the bones of the skull, which are divided into two main sections: the cranium and the face. The cranium encloses the brain, forming the top, back, sides, and base of the skull. It’s made up of eight bones, including the frontal, occipital, sphenoid, and ethmoid bones, as well as two temporal bones and two parietal bones.

The frontal bone forms the forehead, part of the floor of the cranium, and most of the roof of the eye sockets, also known as the orbits. It also contains two frontal sinuses, which are air-filled cavities located above each eye.

The two parietal bones form most of the top and upper sides of the cranium and a small portion of the base of the skull.

The two temporal bones form the sides of the cranium and part of the base;

they enclose the structures of the ear;

and form part of the temporomandibular joint, or TMJ, which allows movement of the jaw.

The occipital bone forms the back of the cranium and a large portion of the base of the skull and contains an opening, called the foramen magnum, where the spinal cord passes through and connects to the brain.

The sphenoid bone forms part of the base of the skull and contributes to the structure of the eye socket. Finally, the ethmoid bone forms part of the nasal cavity, part of the base of the cranium, and contributes to the structure of the eye sockets.

These bones join together at immovable fibrous joints called sutures, which help hold the skull together. The main sutures are the coronal suture that joins the frontal bone with the parietal bones; the sagittal suture joins the two parietal bones; and the lambdoid suture joins the parietal bones to the occipital bone.

Next, let’s look at the 14 bones of the face. These bones support the eyes, nose, and oral cavity, as well as the muscles responsible for chewing and facial expression. Important facial bones to know in dental settings include the maxilla, mandible, zygomatic bones, nasal bones, lacrimal bones, palatine bones, and vomer.

The maxilla forms the upper jaw, supports the upper teeth, forms the anterior part of the hard palate, and contains the maxillary sinuses that are located just under the eyes on either side of the nose.

The mandible, or lower jaw, is the strongest and only movable bone in the skull, enabling chewing, speaking, and swallowing. Important features of the mandible include the mental foramen, which is an opening that allows passage of nerves and blood vessels, and the condylar process, which articulates with the temporal bone at the temporomandibular joint to allow movement of the mandible.