ANATOMY

Detailed explanation-1: -The orbicularis oculi muscles circle the eyes and are located just under the skin. Parts of this muscle act to open and close the eyelids and are important muscles in facial expression.

Detailed explanation-2: -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-3: -Orbicularis Action The orbicularis oculi muscle is innervated by cranial nerve VII (the facial nerve). Contraction of the palpebral portion closes the eyelid gently, and the palpebral orbicularis is the muscle of action in an involuntary blink and a voluntary wink; relaxation of the levator muscle follows.

Detailed explanation-4: -The levator palpebrae superioris (LPS) is an important muscle, as it opens the eye and is innervated by cranial nerve III.

Detailed explanation-5: -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.