A Very Important Spinal Bone/Nerve: C1 (Atlas)
Author: Dr. Chris Demczar, DC, MS,CSCS
The first bone in your neck is one of the most distinct and unique spinal bones: The Atlas(Cervical Bone #1)-named after Greek mythology where the titan Atlas carried the weight of the celestial sky upon his shoulders (interesting to note; It was not the weight of the world that was carried, as is so common to believe today, it was the weight of the universe!). So it is easy to see how the top vertebra of the spine, that supports the entirety of the skulls weight above it, got its nickname
The articulations of the Atlas is with the skull above, and the C2 cervical vertebra below. The Atlas bone primarily allows you to look up and down as to say “yes/no”, to look left and right and also to tilt our head ever so slightly to one side similar to when you see a cute puppy begging for food. Further, the Atlas bone has a special connection with the bone below, which allows for you to look nearly all the way behind yourself to protect us from threats that may be coming from behind
This bone also has the largest hole (foramen) in the middle of it of all spinal bones. This serves two anatomical purposes; the foramen is larger to accommodate the brain stem and spinal cord as it exits the skull and provides a cushioned channel for the nearly 100 billion nerves that travel through the brain stem into your neck and ultimately every organ and cell of your body
Question: Can spinal subluxations at Atlas cause issues to the brain stem? Answer: Since the spinal cord and brainstem are directly connected and meet around the Atlas bone, this is a strong possibility. There are numerous mechanisms that can cause C1to subluxate, and its one of the reasons that C1 is so heavily studied and very commonly adjusted during a chiropractic visit.
Going a little deeper into the anatomy, notice those two small holes just outside the ear looking pieces of the bone (see image above)? Those have an extremely important task too. They are part of the pathway for the vertebral arteries, carrying critical blood supply to our brain, spinal bones, discs, and other soft tissues in our brain and spine. This implies that proper alignment of the atlas plays an important role in ensuring your brain is supplied with enough blood for normal function. When the atlas is misaligned and blood flow is compromised decreases in blood to the brain can result in dizziness/lightheadedness, loss of balance/coordination, numbness/tinging, visual disturbances, tinnitus (ringing in ears),headaches, difficulty swallowing and even confusion.
Question: Can an Upper Cervical Chiropractic adjustment cause a stroke? Answer: No. This commonly gets brought up since it’s theorized that any rotation of the atlas bone could potentially create enough torque on the vertebral artery to cause damage and potentially hemorrhage. This myth has been disproved countless times in research. There is not any possible way to cause damage to the vertebral arteries during an adjustment. The adjustment is a gentle input at a specific vector and range of motion that is meant to release a spinal joint, removing interference within our central nervous system. Any movement that could cause the artery to rupture would be classified as a gross traumatic manipulation, and that is not something that should be or could be done during a chiropractic office visit.
Question: Where do the spinal nerves from C1 go? Answer: The nerves exiting off of C1 influence the muscles of your tongue, one of the strongest muscles in your body. These nerves also branch into the deep muscles of your neck allowing movements forward, backward, and to the sides. Some of the muscles controlled by your C1 nerve roots even interact directly with the central nervous system through dural attachments, forming a myodural bridge, which when interfered with are the number one cause of headaches and neck pain.
The most common injury to this bone is called the Jefferson fracture, and this is when someone gets hit square on the top of the head, or collides head first into something, as seen in diving accidents. The atlas bone splits into 2 or more segments and requires extraneous intervention to correct the fracture.
Has this article peaked your interest in learning more about the individual segments of your spine? Be on the lookout for future articles highlighting more spinal bones and nerves and their connection to your health.