Anterior View of Skull

Anterior View of the Skull:

This section includes the anatomy of the Forehead and the bones around the nasal region that forms the Facial skeleton.  In total the viscerocranium is composed of 14 bones.  Let us start with them main bones that are:

• The Frontal Bone
• Zygomatic Bone and Nasal Bone
• Sphenoid Bone
• Ethmoid Bone

The Frontal bone is a large bone that forms the forehead, the temporal fossa, superior part of the orbit, and the roof of the orbital cavity.

Inferiorly, it forms the superior rim of the Orbital Cavity. On the medial side of this part of the orbit are present, the Supra Orbital Foramen.  Just above the Superior rim of the orbit is large, visible protuberance –The Supercillary Arches- which dips down, medially into a depression called Glabella.

Laterally the Zygomatic process of the frontal bone articulates with the Frontal process of the zygomatic bone. This also forms the superiolateral part of the orbit. Similarly the frontal process also forms part of the superior medial process of the orbit.

Within the frontal bone -just above the orbital margins- are two hollow spaces lined by mucous membranes called the Frontal Air Sinus.

The Zygomatic bone articulates superiorly with the frontal bone via frontal process of the zygomatic bone. It forms mainly the inferiolateral and part of the inferior rim of the orbit. Medially the zygomatic process of the maxilla articulates with the body of the zygomatic bone. It extends laterally and posteriorly to articulate with the zygomatic process of the temporal bone to form the Zygomatic Arch. We will look at that in detail in lateral view of the skull later. It also forms the lateral wall of the orbital cavity.

The Nasal bones form the bony part of the nasal cavity. They articulate with one another medially, and with the frontal bones superiorly at the Frontonasal Suture. This region is also called the Nasion. Laterally they articulate with the frontal process of the maxilla. The periform aperture is the largest cavity in the nasal region and also forms the anterior opening of nasal cavity. The periform aperture is separated into right and left nasal cavity by the nasal septum. The bony nasal septum is formed by the two fused nasal crest that also gives rise, anteriorly to the Nasal Spine. Behind the nasal bones are the paired lacrimal bones, which house the lacrimal duct.

The Maxilla is the part of the facial bone between the inferior rim of the orbit and the upper teeth. Superiorly the maxilla gives rise to the inferior rim of the orbit and most of the floor of the orbital aperture. There, it also articulates with the frontal bone via frontal process of the maxilla superiorly and with the nasal bones medially. Laterally the zygomatic process of maxilla articulates with the zugomatic bone. It forms the major part of the lateral and inferior border of nasal cavity. Between the nasal cavity and the alveolar process (that holds the teeth) is the body of the maxilla.

Inferior to the inferior rim of the orbit, on the body of the maxilla is the infra-orbital foramen.  Within each maxilla is a large pyramidal shaped cavity lined with mucous membrane called the Maxillary Sinus.

Sphenoid Bone has two major parts, the greater wing and the lesser wing. The greater wing forms most of the lateral wall of orbital cavity. The greater and the lesser wing are separated by medial triangular gap called the sub orbital fissure.

Ethmoid Bone forms the medial wall of the orbital cavity. These two bones will be discussed in detail in later sections.

The Mandible, although not part of the facial skeleton is discussed next. The mandible has two parts:

1.       The body

2.       And the ramus

These two meet posteriorly at the angle of the mandible. The body of the mandible is further divided into two parts, namely:

1.       The base of the mandible

2.       And the alveolar process of the mandible.

The base of the mandible has median swelling called the symphysis menti, below which is a visible protuberance, the Mental Protuberance. On either side of the mental protuberance –laterally- are the tubercle of the mandible. Laterally, at the oblique line of the mandible, are openings called external mental foramen.

The mandibular condyles articulate with the temporal bone at the temporomandibular joint. Inferior to the condyle is a sharp projection called the coronoid process. Between the two is mandibular notch.