GENERAL HISTOLOGY

Detailed explanation-1: -Orbicularis oris muscle The orbicularis oris is a circular composite muscle that surrounds the mouth and forms the majority of lips. It consists of two parts; labial and marginal, with the border between them corresponding to the margin between the lips and the surrounding skin.

Detailed explanation-2: -In human anatomy, the orbicularis oris muscle is a complex of muscles in the lips that encircles the mouth. It is a sphincter, or circular muscle, but it is actually composed of four independent quadrants that interlace and give only an appearance of circularity.

Detailed explanation-3: -The buccal branch of the facial nerve, or cranial nerve VII, provides motor innervation to the orbicularis oris and elevators of the lip and lip angle.

Detailed explanation-4: -Orbicularis oris muscle along with the buccinator and pharyngeal constrictor form a functional unit, known as “buccinator mechanism” which has an important role in orofacial function (swallowing, sucking, whistling, chewing, vowel pronunciation, kissing).