The Muscles of the Ox

Muscles of the Face

The panniculus is much more developed than in the horse, presenting as a special feature the extensive frontalis muscle, which covers the frontal and nasal regions.

The orbicularis oris does not form a complete ring, the defect being in the middle of the upper lip.

The levator nasolabialis is extensive, thin, and not very distinct from the frontalis; it divides into two layers, between which the levator labii superioris proprius and the lateral dilator of the nostril pass. The superficial layer ends in the nostril and upper lip, the deep layer on the accessory (lateral) nasal cartilages and on the nasal process of the premaxilla.

The levator labii superioris proprius arises on and before the facial tuberosity and terminates by several tendons in the muzzle. It passes between the two layers of the preceding muscle, blending in part with the deep layer.

The zygomaticus is much stronger than in the horse. It arises on the masseteric fascia, and ends chiefly in the upper lip.

The depressor labii superioris does not resemble the muscle of the same name in the horse. It arises just in front of the facial tuberosity, and divides usually into two branches, which terminate in a number of tendons that form a network in the muzzle and upper lip.

The incisivus inferior is a small, rounded muscle, which arises on the body of the mandible below the second and third incisors, and ends in the lower lip, blending with the orbicularis.

The depressor labii inferioris is thin, and does not extend as far backward as in the horse; only the anterior end is distinct from the buccinator.

The buccinator shows no marked variation, but its superficial layer is well developed.

The dilatator naris lateralis arises in front of the facial tuberosity, passes forward between the branches of the levator nasolabialis, and terminates in the outer wing of the nostril.

The dilatator naris transversus is replaced by the dilatator naris apicalis, which is situated in the muzzle and joins its fellow at a median raphé. It arises on the border and upper surface of the body of the premaxilla, the fibers passing obliquely upward and outward to the inner wing of the nostril.

The dilatator naris superior arises from the alar cartilage of the nostril and ends in the inner wing of the nostril.

The dilatator naris inferior consists of two layers which arise on the nasal process of the premaxilla and the lateral nasal cartilage and end in the outer wing of the nostril.

The orbicularis oculi is well developed.

The corrugator supercilii is not present as a separate muscle, its place and function being taken by the frontalis.

The malaris is broad, and spreads out below on the fascia over the buccinator and masseter; it is divided into two parts.