One of the most commonly treated complaints in chiropractic offices is headache. While there are many types of headaches with varying causes, the most common type is the "Muscular Tension Headache."

Tension headaches generally result from prolonged contraction of the suboccipital muscles. These muscles bridge the junction between the posterior (back) of the skull and the vertebrae (bones) of the cervical spine (neck). Several mechanisms seem to be involved in the causation of the common headache: 

Today more than ever people are inclined to sit for hours with contracted postural muscles but without substantial physical activity. When muscles contract they burn fuel and produce waste. Among the waste products of muscle contraction are lactic acid, histamine and bradykinins. These waste products are irritants. If they are not efficiently removed from the muscle they can cause muscular inflammation, pain and accumulate into localized tender areas known as "trigger points."

These waste products should normally be diluted and removed from the muscle tissue by the circulation. This process relies on the normal "contract - relax" cycle in the muscle. When the muscle contracts it creates a high pressure on the fluids inside the muscle and pushes the blood out carrying away muscular waste products. When the muscle relaxes the pressure falls and blood floods back in carrying vital nutrients and fuel.

When we sit or stand we are using the many back and neck muscles required to support our body. When these muscles are held contracted for a prolonged time (hours spent sitting or standing), they are producing irritative wastes, but not relaxing and draining themselves of these irritants. Over time these irritants can cause the muscles to lose their natural suppleness and resting length becoming stiffened and shortened. These stiffened and shortened muscles, often accompanied by trigger points can cause reflex pain into the neck and head.

Joint Irritation and Nerve Compression

The vertebrae of the spine fit together on moving joints that provide strength to the structure of the spine and maintain the vertebrae in proper working alignment with one another. The joints of the spine in the neck are richly innervated (supplied) with nerve fibers that can cause pain in the head and neck if the joints are physically strained or injured. 

Once the above process has produced stiffness and shortening of the muscles in the neck the joints of the spine are no longer properly stabilized or supported. The affected joints of the spine often become subluxated (misaligned). This causes strain and injury to the joints and supporting ligament tissue. The result of the combined subluxation, ligament strain and joint injury is often neck pain with associated headache.

Dural Traction on the Spinal Cord and Brainstem

The brain and spinal cord are enclosed within a protective covering known as the "meninges." The tough outer layer of the meninges is known as the "dura matter." If this covering becomes inflamed you can experience severe headache, neck pain and mental affects. The diagnosis of "meningitis" refers to an inflammation of the meninges.

In 1996 a team of investigators at the University of Maryland were dissecting the region of the spine at the base of the skull in a manner atypical to the standard dissection technique for the neck. They took this atypical approach because they were in fact not interested in the neck structures but were intending to study the muscles of the jaw. What they found was a hitherto undiscovered anatomical structure that connects the dura covering the spine at the level of the brainstem to a neck muscle that bridges between the skull and the spine. It is now realized that this structure has the potential to exert a tractioning pull on the dura resulting in neck pain and headache. 

Their findings were reported in the "1998 Medical and Health Annual" printed by the Encyclopedia Brittannica. This publication states: "Spinal manipulation as a treatment for tension headache is predicated upon the assumption that dysfunction in the neck muscles contributes to (the) head pain: in the U.S. 90% of such procedures are performed by chiropractors. The muscle-dura connection may represent, at least in part, the underlying anatomic basis for the effectiveness of this treatment. Such treatment, as performed by a chiropractor, would decrease muscle tension and thereby reduce or eliminate pain by reducing the potential forces exerted on the dura via the muscle-dura connection."
Glen Nykwest D.C., D.A.B.C.O.