Muscles of the head of Horse

The cutaneous muscle of the head is less developed.
The orbicularis oris is a complete sphincter.
The levator labii superioris proprius inserted by a common tendon with its fellow to the upper lip.
The depressor labii superioris is absent.
Transversus nasi is unpaired and lies between the nostrils.
The corrugator supercilli is a separate muscle.
Malaris is thin and levator buccalis is absent.
There is an additional muscle in the mandibular region the occipito-mandibularis, which extends between the paramastoid process and the posterior border of the vertical ramus
The digastricus has a distinct intermediate tendon, which perforates the tendon of stylo-hyoideus.
Thyro-arytenoideus is represented by ventricularis and vocalis.
Other muscles resemble those of the ox.