Why is the Upper Cervical Spine at Risk of a Subluxation?
Jarek Esarco
There are anatomical and physiological factors that contribute to the likelihood of an upper cervical subluxation. The upper cervical spine is complex, both in structure and function. To simplify things, let's focus on three characteristics.
Superior Spinal Cord/Inferior Brainstem
The Central Nerve System includes the brain, brainstem and spinal cord. Within the spinal column, we will find the spinal cord and part of the brainstem.
Nerve fibers, or axons, are long projections off a nerve cell that transmits electrical signals. The Central Nerve System uses nerve fibers to send and receive messages. These messages are vital for muscle movement, organ regulation, sensation and perception. This is critical to health and homeostasis.
The greatest accumulation of nerve fibers is found at the level of the upper cervical spine, where the superior spinal cord intertwines with the inferior section of the brainstem. The inferior section of the brainstem is the switching station for nerve fibers between the brain and spinal cord. Nerve fibers from the brain and the spinal cord convene here to organize, relay and integrate information.
As we travel down the spinal column from the upper cervical spine, the spinal cord overall decreases in size. Nerve fibers branch off the spinal cord between the vertebral bones on their way down the spine. The opening between each bone where nerves come off the spinal cord is called an intervertebral foramen, or IVF for short.
Spinal Canal
The spinal canal is the passageway for the spinal cord and brainstem. It comprises bones, ligaments and other tissue surrounding and protecting the vital Nerve system. The main protector is the vertebral bones. Bone, or skeletal tissue, is the hardest and most durable tissue in the human body. It protects the softest and most delicate tissue in the body, nerve tissue.
Compared to the rest of the spinal column, the spinal canal diameter is the smallest in the upper cervical spine. Overall, the spinal canal diameter increases in size as it travels downward. The intervertebral foramen (IVFs) also get bigger as they go down the spine.
Spinal Mobility
Mobility allows us to better interact with our environment through our five senses. The spinal column is involved in the majority of movements the body makes.
The lower we go down the spine, the less mobility we find. The higher we go up the spine, the more mobility we find.
The greatest amount of mobility we have in the spine is at the upper cervical spine. The upper cervical spine alone accounts for 50% of all the movement in the cervical spine.
The more mobility a joint has though, the less stable it is. Less stability means more vulnerability to injury. It is a compromise the body makes.
For example, the shoulder has more mobility than the elbow. This means it is less stable than the elbow. It also means it has the potential to shift out of its normal joint more easily, injuring the elbow.
If we consider the facts about the upper cervical spine, we can draw some conclusions as to why it has the potential to be misaligned.
In the upper cervical spine, the spinal cord/brainstem diameter is the largest and the spinal canal diameter is the smallest. This means that, compared to anywhere else in the spinal column, the bones of the upper cervical spine are in the closest proximity to the spinal cord and brainstem. Furthermore, the top bones of the spine are nearest to a significant concentration of nerve fibers. Finally, the upper cervical spine is the most vulnerable to injury because it has the greatest mobility of the spinal column.
Vertebral Subluxation
A specific injury to the upper cervical spine, called a vertebral subluxation, approximates the top bones of the spine even closer to the spinal cord.
A vertebral subluxation is when the bones of the spine shift and lock out of place. This puts added pressure on the surrounding tissue, specifically nerve tissue, and interferes with how it functions.
Quoting Dr. Michael Kale, DC, the upper cervical spine is “more liable to have a possible subluxation with more occlusion; more pressure; more interference to transmission” than anywhere else in the spinal column. Dr. Kale goes on to say that “the location of the fibers that are subject to pressure which supply the entire body, either directly or indirectly, are in the medulla oblongata [inferior section of the brainstem] in the region of the atlas and axis.”
When nerve function is interfered with, it creates nerve disruption. Nerve disruption negatively effects how messages about muscle movement, organ regulation, sensation and perception are controlled. Health and homeostasis are altered.
Jarek Esarco, DC, CACCP is a pediatric, family wellness and upper cervical specific Chiropractor. He is an active member of the International Chiropractic Pediatric Association (ICPA). Dr. Jarek has postgraduate certification in Pediatric Chiropractic through the ICPA. Dr. Jarek also has postgraduate certification in the HIO Specific Brain Stem technique through The TIC Institute. Dr. Jarek is happily married to his wife Regina. They live in Youngstown, Ohio with their daughter Ruby.