The viscerocranium (or splanchnocranium) is one of the two areas that make up the skull. It is situated anteriorly to the neurocranium which partly encapsulates it posteriorly, both from above and below. The viscerocranium comprises several bones that form the skeleton of the face as well as parts of the jaw (facial skeleton).
The Nasal Bones
A pair of bones that sit at the roof of the face and create the initial contour of the nose known as the bridge of the nose. They meet in the midline with one another and additionally articulate with the frontal bone superiorly via the frontonasal suture and the maxilla laterally via the nasomaxillary sutures.
This bone makes up the largest portion of the face and has the most muscle tissue attached to it, which is responsible for facial expressions. As the nasal bones it also connects to all the bones within the bony orbit (except the frontal bone).
The Zygomatic Bone
The zygomatic bone is the bridge between the neurocranium and the viscerocranium. It forms the lateral prominences of the face (“cheekbones”) where the zygomatic and temporal portions of the zygomatic arch meet each other. It also articulates with the maxilla via the zygomaticomaxillary suture and the frontal bone via the frontozygomatic suture. Inside the bony orbit it contacts the frontal bone, the sphenoid bone and the maxilla.
The mandible forms the chin and the jaw line contours of the face and allows a person to speak, chew and open their mouth. To be precise, the mandible is not part of the skull but a separate bone that articulates with it through the temporomandibular joint (TMJ). Nevertheless it should be mentioned when discussing facial bones.
The Lacrimal Bone
The lacrimal bone can be found on the medial wall of the bony orbit. It houses the lacrimal sac and supports the contents of the eye socket. Anteriorly it is surround by the maxilla, superiorly by the frontal bone and posteriorly by the ethmoid bone.
The Ethmoid Bone
The ethmoid bone consists of a horizontal and a vertical plate. From the bony orbit only the vertical plate can be seen on the medial wall. It cascades down from the roof of the nasal cavity and separates it into two nasal passages. Its appendages include the superior and middle nasal conchae. Within the bony orbit it is surrounded anteriorly by the lacrimal bone, superiorly by the frontal bone, inferiorly by the maxilla and the orbital process of the palatine bone and posteriorly by the sphenoid bone.
The Sphenoid Bone
The greater and lesser wings of the sphenoid bone make up the posterior wall of the bony orbit. They contain all three orifices including the optic canal and the superior and inferior orbital fissures. The sphenoid bone is surrounded by and in contact with all of the bones that make up the bony orbit.