Frontal Bone of Domestic Animals

The frontal bone is a prominent, unpaired cranial bone located on the dorsal aspect of the skull. It forms the entire roof of the cranium in most domestic animals.

The shape and size of the frontal bone influence the appearance of the skull, and it plays a vital role in protecting the brain and supporting facial structures.

Frontal Bone of Ox

The frontal bones are situated on the dorsal aspect of the skull and form the entire roof of the cranium. They are the largest of the cranial bones.

The characteristic appearance of the skull is largely determined by the shape and size of the frontal bones. Each bone has a body or frontal part, an orbital plate, and supraorbital processes.

Body

The external surface of the body presents the supraorbital groove, about the middle of which is a foramen—the upper opening of the supraorbital canal.

The supraorbital groove marks the course of the frontal vein.

The bone consists of two tables, between which lies the large frontal sinus. The internal surface forms part of the cranial and nasal cavities.

It meets the parietal bone, and at their junction forms a central prominence—the frontal eminence (torus frontalis). At its posterolateral angle is a large conical process.

The horn core (flint or cornual process) is excavated to form part of the frontal sinus. The horn core varies greatly in size, length, and curvature among different animals and breeds.

In the above figure of the horn, you can easily see how the frontal bone forms the cornual process or horn core for the horn in animals.

The anterior end, together with its fellow, forms a notch to receive the two nasal bones.

Orbital Plate

The orbital plate of the frontal bone forms the medial wall of the orbit. It presents the orbital opening of the supraorbital canal.

Close to the posterior edge is the ethmoidal foramen. The medial surface meets the sphenoid and ethmoid.

Supraorbital Process

The supra-orbital process of the frontal bone forms a part of the posterior rim of the orbit. Its medial face is related to the lacrimal gland.

The supraorbital process of the frontal bone meets below the frontal process of the malar.

Comparative Anatomy of Frontal Bone

The frontal bone varies significantly among domestic animals in size, structure, and function.

Horse

• The frontal bone of the horse is situated between the parietals behind and the nasals in front and is relatively smaller than in the ox.
• The supraorbital foramen perforates the root of the supraorbital process, which joins the zygomatic process of the squamous temporal.
• The horn core is absent in the horse. The inferior borders of the two bones form a projection that fits into the notch formed by the two nasal bones.

Dog

• The frontal bone of the dog is located and extends similarly to that of the horse. The external surface is crossed by a frontal crest, which curves from the parietal crest to the supraorbital process.
• The frontal parts show a central depression and slope downward and forward.
• In front, there is a narrow nasal part that fits between the nasal bone and maxilla.
• The supraorbital process is short and blunt, and the orbital rim is incomplete.
• The supraorbital foramen is absent, and two ethmoidal foramina are present.

Fowl

• The frontal bone of the fowl is the largest bone of the cranium. It consists of a body and an orbital plate.