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Masseter Muscle

The masseter muscle is one of the muscles of mastication. Read on to know about its structure, function and problems that may be seen in relation to this muscle...
Dr. Sumaiya Khan
There are many different types of muscles in the body that help us perform different kinds of functions. One group of muscles that are present are called muscles of mastication. They perform the function of moving the lower jaw, that is, the mandible so as to aid in chewing and in talking. They are the masseter, temporalis, and medial and lateral pterygoid.


The masseter is a quadrilateral muscle that covers the lateral surface of the ramus of the mandible. It has its muscle fibers arranged in three layers, which are the superficial layer, middle layer and deep layer.
The superficial fibers originate from the anterior 2/3 of the lower border of the zygomatic arch and the zygomatic process. They are inserted into the lower part of the lateral surface of the ramus of the mandible, as they pass downwards and backwards at a 45 degree angle.
The middle fibers layer comes from the zygomatic arch, and the deep layer originates from the deep surface of the zygomatic arch. The middle fibers are inserted into the middle part of the ramus while the deep fibers go into the upper part of the ramus and into the coronoid process.


The masseter is a muscle that performs many functions. It helps to pull the jaw up, i.e, it elevates the jaw to close the mouth. Thus, it helps in the chewing and clenching of teeth. It is innervated by the masseteric nerve. This is a branch of the anterior division of the major nerve, the mandibular nerve, which in turn is a branch of the trigeminal nerve.


Sometimes, a person may feel pain if this muscle behaves abnormally. Sometimes, it may lead to excessive clenching or may become very tight, which could be painful. This is especially noticed after waking up, when people realize that there jaw is sore. This is also one of the leading causes of teeth grinding.
Some people may also complain of muscle spasms. This is a condition where the person feels pain because of constant uncontrolled spasms. It is not understood as to what leads to the spasms; it may be due to imbalance in the sodium-potassium amount in the muscle.
This leads to a condition known as myofascial pain syndrome. This is a condition where there is deep set pain, often due to the involuntary action of both the masseter and temporalis muscles.
Due to the nature of the disease, there isn't any single treatment option but instead, one can opt for myofascial release so as to ease the pain. If all else fails, then, one can try taking analgesics or may need more invasive methods of treatment, like injections of analgesics.
One should take symptoms like teeth grinding, and muscle or jaw pain seriously. There are many effects of constant teeth grinding, and jaw clenching. These include the wearing of teeth, risking exposure of pulps.
It may also lead to pain in the temporomandibular joint, which may further lead to conditions like temporomandibular joint disorders. These symptoms should not be overlooked, and one is advised to seek a medical opinion at the earliest.