Over the past 150 years, the arcuate foramen has attracted attention first by anatomists, then by clinicians seeking to understand its significance, and more recently by surgeons whose work demands clarity on the structural landscape of the cranio-cervical junction. The arcuate foramen is a bone arch that shows up sometimes on the first vertebra (the atlas). The vertebral artery and vein, and the first cervical nerve pass through it. Its significance is not understood despite a century of observations.
Two hypotheses describe the origin of this atlas anomaly; a genetic and age-related, possibly mechanical stress-related etiology. A fact pointing to simple heredity includes observations that this structure is more likely to exist in multiple members of the same family. A fact supporting the stress-related hypothesis includes higher prevalence in Turkish women who are more likely to be carrying materials on their heads.
The arcuate foramen is known by other names, including Kimmerle’s variant, ponticulus posticus, posterior ponticle, foramen arcuale, foramen sagittale, foramen atlantoideum posterior, canalis vertebralis, and retroarticular vertebral artery ring. Adolf Kimmerle was the first clinician to describe this structure in a living person 24 years after the invention of the radiograph. Until that point, anatomists were the only contributors to thought about the arcuate foramen, and the only method for assessing potential significance was an imagination influenced by Darwin, Owen and Lamarque. But suddenly, in 1930, with the application of good clinical decision-making to radiographs of a 20-year old German farmer with infections, we became able to discriminate between this clearly demarcated arch over the vertebral artery sulcus and infectious processes, particularly tuberculosis. The question remained whether this arch was capable of causing health issues. The assumption was made but never tested about its effect on vertebral artery circulation. Symptoms such as headaches, neck pain, vertigo and autonomic nerve system disorders became associated with this bony bridge.
Until 1984, contributions from the chiropractic world did not exist. Crowe and Sweat made a significant addition to the literature by clarifying the relationship between the atlas subluxation complex (misalignment of the first vertebrae in the neck) and symptoms. One useful observation regarding the significance of the arcuate foramen lay in the fact that correction of that misalignment was less successful in those cases demonstrating the bridge. The chiropractic subluxation is a misalignment of contiguous vertebrae that has negative effects on the nerve system and the pathology of structures in its immediate influence. And YES, the subluxation can cause headaches.
In 1999, the Scottish chiropractor Stuart Wight actually determined that subjects with an arcuate foramen were significantly more likely to exhibit common migraine (without aura), but failed to make note of how these subjects responded to chiropractic care.
In 1970, the Serbian medical colonel Nicholas Ercegovac, made the rather serious allegation that individuals with the arcuate foramen should be screened out of the military due to the assumption that this anomaly would require future surgery. His paper related the experience of surgical interventions on the cranio-cervical junction in eight individuals. Surgical intervention in the cranial-cervical junction brought about resolution of patient symptoms, some of which were severe.
It would not be fair if we did not recognize that the goal of the health care practitioner is to relieve human suffering and facilitate healing. This goal supersedes any overtly stated frame of reference such as allopathy, homeopathy, chiropractic, or osteopathy. The question is what sequence to use when taking actionable steps toward that goal.
When faced with neurological deficit such as headaches, muscle atrophy, and other symptoms associated with the arcuate foramen, a conservative approach would be favored by most practitioners. Within the chiropractic profession, the subluxation associated with these signs can be structurally and neurologically defined within the orthogonal model of upper cervical procedures. Here’s a list of orthogonal chiropractic techniques that could help correct the subluxation that causes headaches – even in the presence of the arcuate foramen:
1. National Upper Cervical Chiropractic Association is the approach we favor
2. Atlas Orthogonal technique is the approach that most closely resembles (1) in that the force of the adjustment is not felt, but is produced as a vibration moving through tissue.
3. Orthospinology is also very similar depending on the adjusting tool used to produce the adjusting force.
4. Advanced Orthogonal is an outgrowth of the others that has added some clever tools to comprehend the role of asymmetry of the bones of the neck and head.
Each approach has its websites. Check in your area to find out the availability of practitioners of each technique. And remember, a famous person once said, “If chiropractic care does not seem to help, it’s not the principle of chiropractic, it’s the application.” Each of these techniques applies the chiropractic principle with slight differences providing an endless supply of hope for our communities.