The muscle of doubt is the mentalis muscle that is involved in expressing doubt and contempt and it elevates, everts and also protrudes your lower lip and also wrinkles the side of your chin.
Your masseter muscle is what keeps the mouth closed and is one of the four muscles responsible for the action of mastication (chewing).
When the masseter contracts it causes powerful elevation of the mandible causing the mouth to close.
The muscle that is called the kissing muscle is the orbicularis oris muscle which is a muscle that surrounds the mouth and forms the lips.
The orbicularis oris muscle is often called the kissing muscle as it is what enables you to pucker.
Orbicularis oris muscle, also known as musculus orbicularis oris is a complex, multi-layered muscle which attaches through a thin, superficial musculoaponeurotic system to the dermis of the upper lip and lower lip and serves as an attachment site for many other facial muscles around the oral region.
In common language, the orbicularis oris is often referred to as 'the kissing muscle.
It allows for facial expression, and more specifically, it is responsible for puckering the lips.
While this action is a requirement for kissing, the puckering action is used in a number of other ways.
A sphincter muscle closes circumferentially.
Therefore, the orbicularis oculi muscle plays a vital role in facial expression and various ocular reflexes such as frowning, squinting, and eye closure.
There is a palpebral portion that can be contracted actively and passively.
Kissing can involve a variety of different facial muscles, with the orbicularis oris being the main skeletal muscle involved.
Simple kisses use as few as 2 muscles and burn only 2 to 3 calories, whereas passionate kissing can involve as many as 23 to 34 facial muscles and 112 postural muscles.
The orbicularis oris muscle is supplied by the buccal and mandibular branches of the facial nerve.