The skull is formed mainly by flat bones interlocking together. There are 34 bones making up the complex structure. The flat bones are joined by cartilage at birth, as the horse matures the cartilage is replaced by bone.
Head motion is controlled mainly by the neck muscles. Deep muscles attaching the head to the neck work with the occipital bone which comes together with cervical vertebrae 1 (C1) assist in moving the head. The muscle most responsible for movement is the rectus capitis dorsalis. This muscle extends the head outward.
The superficial muscles are what allow the horse to have expression. Most of the expressive muscles originate on the frontal, nasal and maxilla bones.
The ear is moved by a complex system of 17 muscles acting like a ball and socket joint. Ears are formed by cartilage, a firm, whitish, flexible connective tissue that when damaged does not repair or grow back.
Each eye has its own set of eyelids acted upon by 4 muscles. Horses have an inner lid that sweeps across the eye as well as the exterior top and bottom lids. The orbicularis oculi muscle encircles the eye and is responsible for the opening and closing of the lids.
Sculpt the head from skull to skin in our upcoming anatomy 1 course. Register today!