Jaw Pain – What other causes besides the teeth and jaw?
My jaw and the area around my upper jaw below my eye hurts. My dentists says that there are no problems with my teeth or jaw. What else could it be?” - SY, Singapore
Pain around the jaw area can be caused by either (i) a problem in the jaw ( Temporomandibular joint) or (ii) pain that is referred from another structure to the jaw. As you have ruled out option (i), then it is likely your pain is caused by the latter.
There are many structures that can refer pain to the facial area, these include nerves that supply the muscles of the face or even the muscles themselves can be a cause of referred pain. With reference to your description above regarding the distribution of the pain, it is likely that your pain is caused by trigger points in the muscles of the face and jaw.
What are trigger points?
Trigger points are described as hyperirritable spots in skeletal muscle that are associated with palpable nodules in taut bands of muscle fibers. Trigger point researchers believe that palpable nodules are small contraction knots and a common cause of pain. Compression of a trigger point may elicit local tenderness, referred pain, or local twitch response. The local twitch response involves a small twitch in the muscles but without the whole muscle contraction.
The trigger point model states that unexplained pain frequently radiates from these points of local tenderness to broader areas, sometimes distant from the trigger point itself. The trigger points have identified reliable referred pain patterns, allowing practitioners to associate pain in one location with trigger points elsewhere.
Which trigger points can refer to the area of the jaw and cheek?
The Sternocleidomastoid muscle (SCM).
The SCM is a strap muscle that is located in front of the neck (if you have very pronounced SCM, you will see a pair of muscle that forms a “V” shape when you look into the mirror). This muscle acts to bend the head forward, and side bends the head to one side while rotating the head to the other. This muscle is most likely to be injured when in a rear end collision. This muscle also works very hard when your head is held in a head forward posture. In the asthmatic or patient suffering from emphysema, their SCMs will be over developed and tight as this muscle can be used to assist breathing.
The muscle refers two distinct pain patterns from active trigger points. The first pattern of referral is to around the eye area, base of the skull and to the jaw area. The other referral pattern is to the ear and forehead, giving rise to ear ache and headache.
The lateral pterygoid muscle
The lateral pterygoid muscle is a jaw muscle that is very deep. The function of this muscle is to enable appropriate joint mechanics with jaw closing and to allow the lower jaw to protrude forward.
An over activation of this muscle can be caused by premature teeth contact and the pain from trigger points in this muscle is felt over the cheek, mimicking sinus pain and over the jaw joint.
This muscle can be palpated by sticking your index finger into the back molar as far as you can go, imagining that you are reaching for the peanut butter that is stucked in the back teeth.
Because the pain referred from this muscle and other masticatory muscles includes the jaw and teeth, it is not surprising that much treatment has been misdirected to the joint and teeth with frustrating results.
The medial pterygoid muscle
The medial pterygoid muscle is another jaw muscle. Its function is to elevate the lower jaw, e.g. when chewing or biting. Pain from the active trigger point is felt inside the mouth (the tongue, the hard palate and the throat area) as well as over the jaw joint and the lower jaw. Sometimes people will describe pain on swallowing.
This trigger point can develop to lateral pterygoid dysfunction as well.
images: wikimedia commons