The masseter muscle is a facial muscle that plays a major role in the chewing of solid foods. The muscle is shaped like a parallelogram, connecting to your mandible (lower jawbone) and your cheekbone.
You have two masseter muscles, one on each side of your jaw. Each muscle is divided into two sections: the superficial and deep portions.
The superficial portion of the masseter is the thick and tendon-like portion of the muscle that connects to your
The masseter muscle is controlled by the masseteric nerve, which is a branch of your trigeminal nerve. The trigeminal nerve is also known as the fifth cranial nerve.
The masseter muscle is the key muscle that elevates your jaw during chewing. It’s assisted by four other muscles:
- medial pterygoid
- lateral pterygoid
The masseter muscle, together with these other four muscles, work together to pull your jaw down and back up again.
The masseter muscle also plays a role in stabilizing your temporomandibular joint (TMJ) when you clench your teeth. Your TMJ is where your jaw attaches to your skull below your ears. It’s a common area of facial pain or tenderness.
The most common types of conditions that affect your masseter muscle are temporomandibular disorders, which are a group of conditions that affect your TMJ or surrounding muscles.
Temporomandibular disorders, commonly known as TMDs, cause pain or tenderness around one or both of your TMJs. According to the National Institute of Dental and Craniofacial Research, TMDs affect up to
TMDs can have many causes, such as:
- grinding your teeth
- repeated jaw clenching from stress
- problems with the facial muscles or joints
Along with jaw pain, additional symptoms of TMDs can include:
- difficulty chewing or opening your jaw
- jaw popping or clicking while chewing
- jaw locking
- throbbing temples
- ringing ears
- changes in teeth alignment
- tight jaw muscles
The masseter and other muscles that elevate your jaw are often affected when it comes to TMD.
Typically, TMD is treated by reducing jaw movements until your symptoms subside. Other factors that may help relieve discomfort include:
- eating soft food
- avoiding chewing gum
- practicing jaw-stretching exercises
- trying stress relieving techniques, like breathing exercises or meditation
If your symptoms don’t get better, your doctor may recommend:
- pain medications
- muscle relaxants
- bite guards or splints
- Botox injections
Your masseter muscle can become hypertrophied, or abnormally large, due to genetic factors, from repeated jaw clenching, or from unknown causes.
An abnormally large masseter muscle is often associated with a
Masseter hypertrophy can also result in restricted movement of your jaw, pain, or headaches. To relieve these symptoms, it’s often treated with:
- mouth guards
- muscle relaxants
- pain medication
Botox injections are also a common treatment option that involves injecting a toxin into the muscle to block nerve signals.
A 2018 study found that the majority of participants who had masseter hypertrophy were satisfied with their results after receiving single or multiple Botox injections.
Surgery can also be used to shrink the masseter muscle. However, because it’s more invasive than Botox injections and comes with more side effects, surgery is used less frequently nowadays.
You have one masseter muscle on each side of your jaw. The masseter is the primary muscle that brings your teeth together when you’re chewing. One side of the muscle connects to your cheekbone and the other side connects to your jawbone.
The most common group of conditions associated with the masseter muscle is TMD. A doctor or dentist can help you find the underlying cause of TMD and recommend the appropriate treatment options.