Does Your Jaw Lockup? Do You Hear Clicking and Popping When You Chew?
Today I will be discussing the TMJ (temporomandibular joint). Many suffer from jaw pain and don’t realize there are treatment options available to them. Today I will go over the anatomy of the jaw, function, and dysfunctions associated with the TMJ. Friday’s post will dive into the treatment options available.
Anatomy
The temporomandibular joints are the two joints connecting the jawbone to the skull. It is a bilateral synovial articulation between the temporal bone of the skull above and the mandible below. This joint is unique in that it is a bilateral joint that functions as one unit. Since the TMJ is connected to the mandible, the right and left joints must function together and are not independent of each other.
The TMJ is comprised of joint capsule, articular disc, ligaments, mandibular condyles, articular surface of the temporal bone, and your lateral pterygoid muscle. The unique feature of the TMJ is the articular disc. The disc is composed of dense fibrocartilaginous tissue that is positioned between the head of the mandibular condyle and the mandibula fossa of the temporal bone. This disc is very similar to the meniscus in your knee and the labrum in your shoulder. The temporomandibular joints are one of the few synovial joints in the human body with an articular disc, another being the sternoclavicular joint (collar bone/sternum).
There are three ligaments that help support the TMJ as well as provide stability within the joint. Two minor ligaments connect the inner ear with the TMJ. The TMJ is a hinging and sliding joint. The TMJ allows for opening, closing, side to side, protrusion (underbite), and excursion (overbite) motion.
Dysfunction
TMJ pain is generally due to one of the four reasons:
Myofascial pain dysfunction syndrome, primarily involving the muscles of mastication (chewing).
Internal derangements, an abnormal relationship of the disc to any of the other components of the joints. Disc displacement is an example of an internal derangement.
Osteoarthritis of the TMJ, a degenerative joint disease of the articular surfaces
Temporal arteritis
Pain or dysfunction of the TMJ is sometimes referred to as temporomandibular joint dysfunction or temporomandibular joint disorder (TMD).
The most common disorder of the TMJ is disc displacement. This is when the articular disc moves out from between the condyle and the fossa, so that the mandible (jaw bone) and temporal bone contact is made on something other than the articular disc. When opening, a “pop” or “click” can sometimes be heard and usually felt indicating the condyle is moving back onto the disk, known as “reducing the joint”. When closing, the condyle will slide off the back of the disc, hence another “click” or “pop” at which point the condyle is posterior to the disc. In disc displacement without reduction, the disc stays anterior to the condylar head upon opening. Mouth opening is limited and there is no “pop” or “click” sound on opening.
Tightness in the muscles of mastication (chewing) can cause pain and limited range of motion in the TMJ. Muscular tightness can also cause the jaw to appear “locked”. The tightness can cause more than jaw pain, it can cause headaches, and tinnitus (ringing in the ear) and in some cases dizziness.
The TMJ is a small, but complex joint. The information I gave today, is the tip of the iceberg. Stay tuned for Friday’s post discussing the different treatment options available to treat your TMJ pain. Remember you do not have to live with the pain.
Disclaimer: I am in no way diagnosing anyone, if you have persistent pain you need to call your local physical therapist and schedule an appointment.
