“Life is the expression of tone. In that sentence is the basic principle of Chiropractic.” - D.D. Palmer (Discoverer of Chiropractic)
One aspect of the Chiropractic exam involves muscle palpation. Muscle palpation aims to investigate the inherent tone found in the muscles. Investigating this tone helps in the analysis of the vertebral subluxation.
What is tone? One of my favorite definitions of the word tone involves the phrase “healthy elasticity; resiliency.” Tone has the capacity to be durable and flexible at the same time. When I often think about tone, I picture the strings of a guitar. Guitar strings are tuned to a specific key or pitch but are also able to bend and adapt. The ability to maintain a certain set-point while also adapting to change is a distinct characteristic of tone.
Muscle palpation takes technical skill, practice and a “sensitive” touch. It is the art of feeling for the presence of the Innate Intelligence in the spinal muscles.
Intrinsic muscles that attach to the vertebral column are very sensitive to minute stretches. A stretch response initiates when a vertebral bone deviates from its normal position. This malposition is a benchmark of a vertebral subluxation.
The stretch activates the muscle spindles of these paraspinal muscles. Once activated, the muscle aims to restore the normal balance and position of the vertebral bone. This “stretch reflex” is different than the more known and general term, “muscle spasm.”
The reflex of a paraspinal muscle is local, engaging the effected segment only. A muscle spasm often happens in a group of muscles as a more general response to an injury.
“Normal” or healthy muscle tone will result in bilateral paraspinal muscles acting in equilibrium. This means that when in a relative state of rest, the muscles that attach to the spinal bone, from both the left and right sides, are active to the same tonal degree.
If a vertebral subluxation is present, the tonal balance will tilt. This means that the paraspinal muscles stretch and work "overtime” in an attempt to correct the misalignment.
Proprioception aides in determining the setpoint for tonal balance. Proprioception is the “perception of space.” Proprioceptors sense our awareness of position, motion and equilibrium in our given environment.
The 3 main areas of proprioception are located in the inner ears, the eyes, and the muscles of the upper cervical spine.
Proprioceptors found in the upper cervical muscles are called mechanoreceptors. The paraspinal muscles of the upper cervical spine have more mechanoreceptors per surface area than any other region of the body.
Important to note is that a vertebral subluxation is not predicated on pain. Why is that? Nociceptors, the sensors for pain, have a higher threshold for stimulation compared to a mechanoreceptor. Nociceptors need more stimulus to create a pain sensation than a stretch reflex. This means that mechanoreceptors are more sensitive than nociceptors. A stretch reflex is “felt” by the brain easier compared to a pain sensation. It is common to feel the working muscles of a vertebral subluxation without the presence of pain.
Imbalances in the muscles, caused by the stretch response, can contribute to a permanent fixation of the attached bone. This fixation characteristic is one component of a vertebral subluxation. A subluxation attributes to hypomobility, which can damage muscles and connective tissue. A subluxation can also dull mechanoreceptors and nociceptors over time. This can lead to structural compensations such as arthritis.
To feel for a working muscle, you need to compare it to its spinal counterpart. Noting which of the two muscles is more active is the first sign that an effected muscle has a greater tone. They should be in tonal balance.
If there is an imbalance in tone, there is an imbalance in “healthy elasticity and resilience.” Without tone, there can’t be balance. Without balance, there can’t be proper function. Without proper function, there can’t be health. Chiropractic aims to balance tone, function and health through a specific adjustment.
- Jarek Esarco, DC, CACCP
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.
