Which bone is NOT found in the skull of a horse?

The ischium is the bone that is not found in the skull of a horse. Instead, the ischium is a part of the pelvic girdle, which supports the hindquarters. In the context of the horse's skeleton, the skull specifically contains bones that are directly involved in the structure and function of the head.

The maxilla, nasals, and frontal bones are all components of the skull. The maxilla forms the upper jaw and holds the upper teeth, providing structure to the face. The nasal bones make up the bridge of the nose and are crucial for the formation of the nasal cavity. The frontal bone creates the forehead region and houses the frontal sinuses. Each of these bones plays a vital role in the horse's skull, contributing to its functionality, protection of the brain, and support for its sensory structures.

In summary, identifying the ischium as not being part of the horse's skull highlights the clear distinction between the bones associated with the skull and those associated with the skeleton of the hindquarters.