HeadachesCauses of Headaches
About 80% of headaches in the general population are tension headaches, which are headaches caused by a sustained contraction of the neck-shoulder or face muscles. Even migraines, which account for another 13% of all headaches, frequently occur together with tension headaches and improve significantly when tension headaches are resolved.
How can tight muscles cause headaches?
What is myofascial pain?
If any muscle in your body tightens up and maintains that tension for a long period of time, it will eventually develop knots or nodule-like spots inside it. These knots are easy to find because in addition to having a distinct, nodule-like texture, they are tender when pressure is applied to them. These tender knots within a contracted muscle are called myofascial trigger points. (Myo means muscle, and fascia is the connective tissue that holds muscles together.)
Although trigger points are sensitive to pressure, they initially don’t cause any problems. Yet over time, myofascial trigger points start producing a sensation of pain in distant sites. That type of pain is called referred pain, because it originates from places outside of where you perceive it.
Pain referred from myofascial trigger points is called myofascial pain. If left untreated, myofascial pain may become chronic and develop into a condition known as myofascial pain syndrome or myofascial pain disorder.
Each muscle in the body tends to develop myofascial trigger points in specific locations. And each trigger point has a specific, predictable and reproducible pattern of pain referral.
Trigger points in the neck muscles refer pain to various areas of the head and trigger points in the face muscles refer pain to the head and face.
Below are some examples of referral patterns for specific trigger points in the neck muscles associated with tension headaches. The black x sign indicates a trigger point within a muscle and areas marked in red illustrate where that trigger point sends referred pain:
How can neck structures cause headaches?
If joints, discs, or other innervated structures of the neck are inflamed or irritated, you may feel a headache, neck pain, or both. This happens because of the sharing of nerve tracts between your neck and head areas.
If something irritates a structure in your neck, your neck’s pain receptors pick up the pain signals and send them along nerve fibers to the spinal cord, and from there to the brain. The brain then interprets the signals and you become aware of pain. The nerves traveling to the brain inside your spinal cord form special “tracts”. (These tracts can be compared to roads along which nerve impulses travel to the brain). Your neck and head nerve fibers use the same spinal tract, which creates a potential for confusion. When a neck pain signal reaches the brain, due to intermingling of the neck and head sensory nerve fibers inside the spinal cord tract, the brain may “think” that the signal actually originated in the head. In this case you will feel a headache, even though what really hurts is your neck.
What causes the “headache muscles” to become tight?
- Behavioral and life-style causes
- Poor posture (forward head, slumped shoulders)
- Daily work in a seated position (e.g. computer work) or in a position that requires looking down for long periods of time (e.g. jewelry making, knitting, using a microscope)
- Prolonged activities involving repetitive hand and arm movements (e.g. work on an assembly line)
- Strenuous manual labor or physical activity (especially if performed repetitively)
- Emotional causes
- Emotional or intellectual stress
- Structural and medical causes
- Unbalanced bite
- TMJ disorder
- Grinding or clenching of the teeth
- Eye strain
- Abnormal alignment of cervical vertebrae
- Injury affecting joints or muscles of the neck (e.g., whiplash injury, neck injury due to a fall or blow to the head)
- Degenerative diseases of the neck (neck arthritis, degenerative disc disease, cervical spondylosis)
Note: If your neck muscles are dysfunctional and tight, eventually the joints, discs, and ligaments of your neck will also become affected and will develop mechanical dysfunctions. Conversely, inflamed joints, ligaments and cervical discs will eventually cause tightening of the neck muscles. Because of this, the predisposing factors and possible causes of tension headaches and cervicogenic headaches are practically the same.