ANATOMY

Detailed explanation-1: -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).

Detailed explanation-2: -It closes, protrudes and compresses the lips. Performing these actions, orbicularis oris facilitates speech and helps in producing various facial expressions, such as anger, sadness and others.

Detailed explanation-3: -The orbicularis oris muscle contributes to the form and shape of the lips. Contraction of this muscle closes and protracts the lips (Fig. 2.13). The position and movement of the lips is acted upon by several mimetic muscles that elevate and depress the lips.

Detailed explanation-4: -The orbicularis oculi muscle closes the eyelids and assists in pumping the tears from the eye into the nasolacrimal duct system. The orbital section of the orbicularis oculi is more involved in the voluntary closure of the eyelid, such as with winking and forced squeezing.

Detailed explanation-5: -Closing the lips: orbicularis oris muscle.