While the chewing process is quite complicated, it's usually not something most people even think about unless they have a condition that makes moving the jaw uncomfortable. But behind the scenes of every bite of food you take, there are several muscles working together in your cheek and jaw to perform the task of breaking down your food before you swallow it. One of these is the medial pterygoid muscle.
Medial Pterygoid Location
The medial pterygoid is a masticatory muscle, which means it's one of the muscles we use in order to chew. There are also three other masticatory muscles: the masseter, the temporalis and the lateral pterygoid. Anatomy Next explains that these four muscles are attached to the skull and the lower jaw and are responsible for the movement of the jaw joint.
The medial pterygoid muscle originates at the base of the skull at a bone called the sphenoid bone, and it attaches to a roughened area on the inside of the lower jawbone called the pterygoid tuberosity, according to Anatomy Next. This muscle is controlled by the medial pterygoid nerve, which is a branch of the trigeminal nerve.
What Does the Medial Pterygoid Do?
The medial pterygoid is a versatile muscle that's responsible for three jaw movements, all used for chewing. Anatomy Next notes that you have two medial pterygoid muscles, one on each side of your jaw. If you contract both muscles at once, your jaw moves forward. If you only contract one medial pterygoid, you push your jaw to the opposite side, helping you move your jaw from side to side. Lastly, when your medial pterygoid works together with your masseter and temporalis muscles, you can close your mouth and bite.
Medial Versus Lateral Pterygoid
Due to the similarity of their names, it's easy to confuse the medial and lateral pterygoid muscles. The differences between these two lie in their position, the nerves that controls them and what jaw movements they create. Anatomy Next states that the lateral pterygoid originates partly from the sphenoid bone, the same part of the skull where the medial pterygoid originates, and partly from a structure that extends from the sphenoid bone called the lateral plate of the pterygoid process. The lateral pterygoid also attaches to a different part of the lower jawbone.
The nerve that controls the lateral pterygoid is another branch of the trigeminal nerve called the lateral pterygoid nerve. While the lateral pterygoid muscle helps the jaw move forward and side to side like its medial counterpart, it isn't responsible for closing the jaw.
Have you ever experienced clicking sounds, discomfort, earaches, chronic headaches or difficulty opening your jaw? If so, you might have temporomandibular disorder (TMD), a condition that affects the jaw joint and associated muscles, including the medial pterygoid. A study in the Journal of Maxillofacial and Oral Surgery reports that when examining a patient with TMD, a dentist may discover that the medial pterygoid muscle is tender, along with the masseter and temporalis muscles.
Treatments for TMD after a confirmed diagnosis include muscle relaxants, anti-inflammatory medications, massage therapy, mouth restriction exercises, acupuncture, dental appliances and, in some cases, jaw surgery. Another potential treatment for the pain associated with TMD is injections of botulinum toxin from an oral surgeon. However, at-home methods of relaxing the muscles are often all that's needed to provide relief.
Dental Treatment Complications
After dental treatment, you may experience strained muscles in the mouth and jaw areas, including a tense medial pterygoid. Prolonged periods of holding the mouth open and pressure on the jaw from dental procedures can sprain your medial pterygoid and other muscles in the face and jaw. This can also be worsened if you already experience TMD symptoms. An article in Oral Health states that 50 percent of patients with TMD experienced strained muscles after dental treatment. The strained muscles might have tenderness, a reduced range of motion, swelling and poor muscle function. In most cases of muscle strain resulting from dental treatment, patients can find relief with treatments similar to those for TMD, such as exercises suggested by your dentist, reduced movement, painkillers or a dental splint worn at night.
The medial pterygoid muscle is just one in a set of vital muscles we use for chewing. Working together, these masticatory muscles help us to break down our food and make it easy to swallow. The next time you eat something, think about your medial pterygoid muscle and all that it does for you.