A neurosurgeon and two dentists at the University of Maryland at Baltimore say they have stumbled across a structure in the neck that is new to science, and which might explain how muscle tension can cause splitting headaches.
Dr. Walker L. Robinson, the neurosurgeon; dental school professor Gary D. Hack; and visiting scientist Richard T. Koritzer, also a dentist, say they have found a quarter-inch piece of connective tissue linking a minor muscle deep in the back of the neck to the dura mater -- the highly sensitive membrane that covers the spinal cord and the brain.
The muscle connects the base of the skull to the top of the vertebral column. The front of the muscle is attached to the back of the dura mater that covers the spinal cord just below the base of the brain.
After 500 years of human dissections and anatomical study, Dr. Hack said, "it is extremely rare, if not unheard of, to find a new anatomical relationship. The assumption is that all structures and relationships have been found."
It is not yet proven that the connection is responsible for tension headaches, Dr. Hack said yesterday. "But we know there is a relationship between muscle contraction and headache. We know the dura mater is very rich in nerves for pain. And anything that could pull on or cause traction on the dura would be interpeted as headache."
There is some anecdotal evidence of a link between the muscle and headache.
Dr. Robinson said he frequently cuts through this neck muscle to repair broken neck bones. Because the muscle is a minor one, he does not reattach it. Some of those patients have later reported that their tension headaches have disappeared.
He now plans to gather data more systematically, asking patients before and after neck surgery about their experience with headaches.
Severing the muscle is too drastic ever to be prescribed as a cure for headaches, the doctors said. But anything that might relax the muscles in the neck could help.
"Maybe an ice pack in the area, massage, various stretching exercises to work out the tension . . . certain manipulative procedures," Dr. Hack suggested. Muscle-relaxing drugs might help, too, but they would have to be prescribed by a physician.
The most immediate benefit of a better understanding of the close relationship between the muscle and the dura mater is that it gives surgeons reason to be more cautious while operating in the area for other reasons.
Doctors Robinson and Hack were to present their findings today in Phoenix, Ariz., at a joint meeting of the American Association of Neurological Surgeons and the Congress of Neurological Surgeons.
Although doctors have long believed that muscle tension in the head and neck region was somehow responsible for certain headaches, it was never clear how muscles on the outside of the skull could produce pain inside. If there was a physical connector, no one had ever found it.
Although his surgical career has made him intimately familiar with the structures of the upper neck, Dr. Robinson said he had never seen the connection. He always approached the area from the same angle, he said, and was always more intent on getting past it to the underlying cervical vertebrae.
But in the course of their study of the chewing muscles, Dr. Hack said, the trio used heads that had been cut in half vertically, from front to rear. It was a totally new perspective.
"And we happened to notice . . . that when we tugged on this muscle, or manipulated it in a manner that simulated movement, the dura moved," Dr. Hack said. "Our initial reaction, when we saw it in the first one, was to say to ourselves, 'This is a very rare anomaly.' Now we have 25 consecutive specimens that show this connection. This is no longer rare."