The mouth is so much more than just the "gateway to the body." You eat and talk with it, but it's also a very important source of nonverbal communication. Often, the first thing you notice about someone when you meet them is their smile. The levator anguli oris (also known as the caninus) is one of the many muscles that work to create your facial expressions. Here's how it functions to help you form your all-important smile.
Location and Function
According to The Muscular System Manual, the levator anguli oris originates from the maxilla, or upper jawbone, just above the canine tooth. It's located to the side of the nose and attaches to other muscle fibers at the outer angle of the mouth. When activated by the buccal branch of the facial nerve, the levator anguli oris contracts, helping to raise the upper lip and pull it back slightly. This isolated movement exposes the teeth and helps you create expressions of contempt and disdain. Most importantly, when the muscle works together with other muscles of facial expression, such as the zygomaticus muscles and the risorius, it helps you form a smile.
Plastic surgery procedures can alter the appearance of your smile if you so choose, and many involve the facial muscles. One such procedure addresses a condition known as a "gummy smile," which occurs when a significant amount of gum tissue becomes visible when a person smiles. The aesthetic issue can be treated through lip repositioning surgery, during which the retraction ability of the levator anguli muscle is limited, notes a study in the Journal of Indian Society of Periodontology. Put simply, the surgery restricts the muscle's ability to pull the upper lip, thereby reducing the amount of gum tissue visible when the person smiles.
Alternatively, the Journal of Contemporary Dental Practice notes that botulinum toxin injections can also treat a gummy smile, providing a more conservative approach than surgery. These injections work by temporarily preventing muscle movement so that the lip cannot be lifted far enough to display excessive gum tissue. These injections can also be paired with surgical techniques to make the patient more satisfied with their smile.
Although rare, strokes can cause paralysis of the facial muscles, including the levator anguli oris, explains a study in the Journal of Neurology. Facial paralysis may also result from damage to the facial nerve or the brain, a brain tumor or a condition called Bell's palsy, according to the National Institutes of Health. If you experience numbness or paralysis in any part of your face, it's important to see your medical care provider as soon as possible so they can identify the cause.
Treatments for any conditions involving the facial muscles — cosmetic or otherwise — should be performed by qualified medical providers. These may include physicians, plastic surgeons, dentists or oral and maxillofacial surgeons. You should always consult with your full medical and dental team before agreeing to any procedure involving the facial muscles. Working together, your healthcare providers will ensure your concerns are addressed and that you're able to enjoy your version of your perfect smile.