VAN 121: Veterinary Gross Anatomy-II (2+2)

MUSCLES OF THE HEAD - DOG

• The facial cutaneous is well developed
• The orbicularis oris is rudimentary
• The levator naso labialis is not divided.
• The levator labii superioris terminates by numerous small tendons, some of which unite with those of opposite muscle. And others are inserted in to the nostrils.
• A triangular muscle which originates inferior to the levator labii superiois represents the dilator naris lateralis. The other dilator muscles of the nostrils are absent.
• The depressor labii inferioris is absent.
• The corrugator supercilli extends from the fascia of the frontal bone and terminates in the upper eyelid at the medial angle.
• The masseter has a remarkable development. It arises from the zygomatic arch and is prolonged beyond the posterior border of the ramus of the manidible. It is thick and its external surface is convex.
• The temporalis is rendered stronger due to the large amount of tendinous material it contains. The muscle is larger as temporal fossa is more developed.
• The lateral pterygoid is not distinct from the medial one.
• The occipito-mandibularis is a strong, round muscle.
• The stylo-hyoideus is in the form of very slender, pale muscular band and kerato-hyoideus is large.
• The occipito hyoideus and hyoideus transversus are absent.
• The parotido auricularis is longer and narrower.
• The parieto –auricularis externus is extensive.
• Both the cervico-auricularis externus and parieto-auricularis internus divide at their termination into two and these are inserted to both conchal and scutiform cartilage.
• The sucto-auricularis externus is not distinct from the parieto auricularis externus.
• Other muscles resemble those of the ox.