The orbicularis oris is a muscle that is located around the mouth and is is responsible for some mouth movements, particularly the ability to pucker the lips when the mouth is closed. It is one of several sphincter muscles located in the human body.
A sphincter muscle is generally shaped like a circle. It works by closing an opening or body passage. The human body contains many sphincter muscles, many of them being so small that they can not be seen with the naked eye.
The orbicularis oris is a more complicated sphincter muscle than some of the others found in the body. While it does consist of numerous muscle fibers, the fibers travel in many different directions. This muscle is made in part from fibers of the lips. Another part of the muscle consists of fibers from other facial muscles which in turn insert themselves into the lips.
Most of the movements of the lips are controlled, at least in part, by the orbicularis oris. In addition to pursing or puckering the lips, this muscle is also used to close or compress them. On occasion, babies are born either without this muscle or with just part of it present. This can cause the affected side of the face to droop somewhat.
The muscle fibers of the orbicularis oris extend upward from the mouth to the septum. The septum is the portion of the nose that is responsible for separating the nostrils. This muscle also extends downward into the area between the bottom lip and the chin. The facial artery provides the blood supply to the orbicularis oris. The facial nerve, also known as one of the cranial nerves, is responsible for the nerve supply to this muscle.
Musicians, particularly trumpet players and the like, use the orbicularis oris extensively when practicing and performing. Constant use of this muscle makes it prone to injury. Rupture of this muscle is a common problem in these musicians and can have devastating effects.
When the orbicularis oris ruptures, overwhelming muscle weakness can occur. The musician then has trouble controlling tone and suffers a debilitating loss of endurance. This condition, often referred to as Satchmo’s Syndrome, has the potential to ruin the career of the musician. Fortunately, there are now surgical procedures available that will often allow the patient to heal and resume playing music.