Structure & Function

Our Central nervous system is made up of the brain and spinal cord which continually monitors and coordinates every single function of the body. The spinal cord is a long bundle of nervous tissue which extends from the lower part of the brain down to your spinal column. It helps relay information back and fourth to the brain. Your vertebra encases your spinal column protecting it and serving as a tool for mobility. The vertebrae however also has many orchestrated outlets within it in allowing nerve branches from the spinal cord to pass through and innervate specific muscles and organs.

A healthy vertebral column collectively sustains appropriate lordotic and kyphotic curves for weight distribution. The natural curves of your spine developed to distribute your body weight at ease. A healthy vertebral column in addition preserves the appropriate intervertebral disk space between each vertebral body allowing you to move freely without compromise to the spinal cord. Several problems can occur with your vertebrae that may alter how well your spinal cord can communicate with your brain and body. These may vary from slight subluxations (an improperly positioned vertebral segment) to fractures, which in severe cases cause lesions in the spinal cord. Depending on the type of injury or the type of “stressor” your vertebrae is experiencing your symptoms may vary. Aside from injuries, degenerative issues are continuously at play with the vertebrae. Your vertebrae will not always up hold the integrity it had when you were just in your teens. Intervertebral disc spaces may decrease in thickness sometimes causing disc bulges and in some instances compressing on the spinal cord disrupting your basic daily functional living due to pain. In other instances the vertebral body itself my decrease from bone loss or compression causing an individual to have the “hunched back appearance.” A very common degenerative cause is the loss or decrease of the spinal curves, which as discussed are intricately designed for weight distribution. Therefore, when weight distribution is distorted, the body begins to suffer from postural imbalance. Postural imbalance within the body leads to irritation and hyper-tonicity of certain muscles due to the overcompensation needed in sustaining balance. The overwhelming compensatory work within these certain muscle after a period of time cause the formation of trigger points “knots” and spasms to occur. Aside from adjusting your vertebrae and treating your symptoms your chiropractor will help you rebalance the deficiencies of your body so that the kinetic chain of dysfunction is eliminated allowing you to ultimately regain the natural curves of your body for full weight distribution and function.

The Inter-Vertebral Disc

The human spinal disc can be described as soft yet tough pads that separate the bones of the spine. These highly specialized structures act as a ligament by holding the vertebrae of the spine together, a shock absorber, and as a pivotal point allowing motion. The adult inter-vertebral disc are considered the largest avascular (no direct blood supply structure in the human body, consisting of three main components being the vertebral end plates, the annulus fibrosus and the nucleus pulposes. The end plates serve as a means of attachment to the bony vertebrae and as a platform form which the avascular discs obtain the nutrients. The vertebral end-plates are biochemically similar to the spinal disc. In fact, the water proteoglycans (specialized protein chains), collagen (a cartilage like substance) and cartilage content of the end-plates mirror that of a spinal disc. This similarity in biochemical makeup helps the diffusion of nutrients into the hungry avascular disc cells.

The annulus fibrosis is the outer layer of the disc and is made of tough fibers for support. It has a higher collagen content and lower water content (60% water) when compared to the nucleus. Its’ function is to contain the pressurized nucleus in the center and to firmly attach the disc to the vertebral end-late and the ring apophysis (bony surface at the periphery of a vertebra). It is made of 15-25 concentric sheets of collagen called the lamella. The lamellas are arranged in a special configuration to give them the strength needed for support and to contain the highly pressurized nucleus pulposa.

The nucleus pulposa is the inner layer of the disc resembling a soft, jelly like substance. It has high water content, which enables it to sustain the downward pressure while standing and sitting. Its function is to bear and carry the weight of the body and act a “pivot-point” which allows for movements. This is the water rich (80%), gelatinous, soft, pulpy, highly elastic, and highly pressurized central structure of the disc. The nucleus is proportionally larger in the cervical (neck) and lumbar (lower back) due to their greater degree of mobility.

The gentle stretching and relaxing of a non-degenerated, healthy spine fosters diffusion through a phenomenon called “imbibition”. Imagine a sponge filled with water, when the sponge is compressed, the water is forced out. When the compressive force is removed, the water is “sucked” back into the sponge. This is imbibition and it is precisely how the nucleus pulpossus stays healthy and functional.

In the simplest terms, this is one method through which a normal healthy disc gets the vital nutrients needed. The other is diffusion enhanced by a phenomenon called “Diurnal Change”. Our bodies have the ability to expand and compress over the course of a day. During the recumbency of sleep, the loading on the inter-vertebraldisc is reduced, ad they are relatively unopposed to swelling pressure. This results in the disc absorbing fluids and increasing in volume.

In fact a non-degenerated healthy disc will expand some 20%, which in turn increases our stature by 19mm. A 19mm change in stature corresponds to change of about 1.5mm in the height of each lumbar disc. This is why our height is actually measurably increased in the morning.

The nucleus is made of a protein called the proteoglycan that attracts water. Normally discs compress when pressure is put on them and decompress when pressure is relieved. When a disc is compressed, its water content decreases; when the compressive forces are taken away, the water levels are normalized. This happens in healthy discs. The change in the water levels of disc is the sole responsibility of the nucleus through a process called imbibition. Imbibition is the method in which the nucleus acquires the life-sustaining nutrients from the end-plate. Without such transfer, the discs in their entirety will degenerate and eventually will cease to function.