The Bones of the Horse Skull

bones of the horse skull

The bones of the horse skull are much bigger than those of other mammals, including humans. They are designed to support the brain, blood vessels, nerves and other structures and to protect them from trauma. This protection includes a complete bony orbit around the eyes. This structure is also important for the ability to blink and to close the eyelids when necessary.

The skull is divided into a cranium and jaw. The cranium is the curved head portion. It is connected to the jaw by two long, curved, slender neck bones called mandibles. The cranium and neck bones are held together by thick fibrous tissue known as dense connective tissue or aponeurosis. This provides a sturdy shock-absorbing frame that holds the limbs and supports the head.

In addition, the skull has a cavity for the brain and a large area for the mouth and teeth. The mouth is designed to crop grass. It has six large incisors at the front and six large squared molars on each side. There is a space between the incisors and molars for a canine tooth (not present in all horses). The ears are set well back on the head, as is typical of grazing animals.

Horses can be quite dangerous if they flip over backward while grazing and hit their heads on the ground or another hard surface. The impact can fracture the sphenoid bone at the base of the skull. Several other bones are also susceptible to injury in this type of accident.

A study of the skulls of a variety of horses has revealed that the rate at which the skull bones grow varies according to age. This first of its kind study could help to explain conditions such as overbite and crowded teeth in some Shetland ponies.

Another bone that varies in different species is the cornual process, which is part of the frontal bone. In some species, such as humans and cats, it extends in and forms part of the orbit. In other species, like dogs and pigs, it extends dorsally and forms a large piece of the skull’s cheekbone. In horses, it forms a notch in the skull called the nasoincisive notch.

In a previous installment of this series we looked at the skeletal anatomy of the head of a horse. In this installment, we’ll look at specific bones of the horse skull in greater detail.