How Your Body Works

In order to fully appreciate the impact that whiplash injuries can have on the human body, it is necessary to talk about how your body works when it is healthy. Because whiplash injuries primarily affect your bones, joints, muscles and nerves – your neuromusculoskeletal system – we will focus our discussion on these areas, and how they cooperate together to give you smooth, controlled, pain-free movement. That is, as long as everything is working correctly.

The last section of this post focuses on the spine. The spine is one of the most complex and unstable structures in the human body and is very easily injured. Because the spine houses the spinal cord and is so tightly situated with all of the spinal nerves that feed every muscle and organ in the entire body, any injury to the spine can result in the abnormal functioning of other systems as well.

Understanding how your body works empowers you to make better choices about your health and to communicate more effectively with your doctors and other health care professionals.

Let’s start off by talking about your bones and joints.

Bones and Joints

The human skeleton is made up of more than 200 bones which are connected by joints. Your bones are responsible for creating your body’s general shape, and they serve to protect your internal organs and to manufacture blood cells. Each of your bones is made up of two compounds: a protein meshwork of collagen and a salt of calcium called hydroxyapatite.

The collagen fibers which make up the basic structure of your bones give them a great deal of resilience and resistance to breaking when twisted, bent or impacted. It is actually the loss of this collagen meshwork and not just a loss of calcium that is responsible for the bone weakness associated with conditions such as osteoporosis. The other component of bone, hydroxyapatite, is a crystalline calcium salt which is integrated into the collagen meshwork. Hydroxyapatite is responsible for giving the bones rigidity and resistance to crushing under pressure.

Bones can be compared to steel-reinforced concrete, where the collagen meshwork acts much like the steel meshwork in the concrete and the hydroxyapatite acts much like the concrete which surrounds the steel. Together they form a very tough, resilient and rigid framework upon which the rest of the body is supported. But because your bones are rigid and do not bend, you would not be able to move if it were not for your joints.

Joints are much more than simply a place where the ends of two bones meet. They are very complicated systems of ligaments, tendons, membranes and cartilage that allow the bones to move in a smooth, stable and controlled way. Joints are designed in a wide variety of ways depending on their function and the particular stresses they have to endure. For example, the joints between your sternum (breastbone) and your ribs are simple joints consisting only of fibrous collagen.  They are designed to be simple because the front part of your rib cage does not have to move very much in relation to your sternum. The shoulder joint, on the other hand, is an extremely complex joint that requires a whole host of muscles, ligaments and tendons all working in concert with each other in order to move properly. If any one of the muscles or other structures of the shoulder are damaged, pain, instability or loss of function may result.

Muscles

There are more than 650 muscles in your body which have only one purpose -to create movement. While your bones are what give your body its framework, the muscles are what give your body motion. There is more than three times the number of muscles in your body as there are bones, and each one of these muscles fills a particular role in creating movement. Like bones, your muscles also contain a lot of collagen for strength and resilience. But instead of calcium salts, muscles contain a specialized type of cell which has the unique ability to contract when stimulated by the nervous system.

There are actually three types of muscle in the body – smooth muscle, cardiac muscle and striated muscle (also called skeletal muscle). Smooth muscle is found surrounding the organs of the digestive tract as well as the arteries.  In the digestive tract, smooth muscle is responsible for moving the food we eat through our digestive system, while the smooth muscle which surrounds the arteries helps the regulation of blood flow throughout the body. Unlike skeletal muscles, smooth muscles are involuntary muscles, meaning that we do not have conscious control over them.

Cardiac muscle, as its name implies, is found only in the heart. What differentiates cardiac muscle from all other muscle in the body is the fact that it rhythmically contracts on its own, regardless of stimulation by the nervous system. As a matter of fact, if two independent cardiac cells, each rhythmically contracting to their own beat are put in contact with each other, they will begin beating in unison. And it’s a good thing,otherwise our heart wouldn’t beat very regularly.

The third type of muscle is skeletal muscle. This is the type of muscle that we can consciously control and the type of muscle that is of most interest to us because it is the type of muscle responsible for our posture and movement. Every skeletal muscle attaches to at least two different bones and as they contract, they draw the bones together, using the joints as hinges, allowing controlled movement to take place.

Take for example the elbow joint. Compared to some of the other joints in the body, such as the shoulder or hip, the elbow is a relatively simple hinge joint. Yet, there are more than a dozen muscles which cross the elbow joint – all of which contribute to the elbow’s normal movement. If any of these muscles do not fire in a highly coordinated fashion, or if some of the muscles are tighter than they should be, or if some of the muscles are weaker than they should be, abnormal joint function and pain
will likely result.

Abnormal posture and joint motion resulting from weak, spasmed or uncoordinated muscles is very common; especially in people who work at a desk all day. Because muscles become weaker unless they are exercised, it is important for good muscular health to include some form of daily exercise as part of your daily routine.

The Nervous System

The nervous system is made up of trillions of highly-specialized individual nerve cells, each of which communicate with hundreds or thousands of other nerve cells through tiny electrical pulses, and is comprised of two major systems. One is called the central nervous system (CNS) which includes your brain and spinal cord, and the other is called the peripheral nervous system (PNS) which includes the nerves that run from your spine to all areas of the body. The nervous system is called the master controller, as it is responsible for the control of all major body functions including our senses, movement and balance, as well as the regulations of all body functions.

There are three types of nerves that are important to our discussion. These are called pain nerves, motor nerves and postural nerves, or more correctly, proprioceptors. Pain nerves do just what their name implies – they allow us to feel pain.  Whenever something in our body hurts, it is because the pain nerves in the area are being stimulated and send signals to the brain to create the sensation of pain. Pain sensitive nerves make up only 10 percent of our bodies total amount of nerves, while the motor nerves make up the remaining 90 percent.

Motor nerves are responsible for controlling our movement by stimulating muscles to contract. The fact that you are able to hold this book in your hands right now is because these motor nerves are contracting the muscles in your hands and arms. If these nerves aren’t able to function correctly, it can result in weakness, or even paralysis, in the muscles they control.

The third type of nerve is the proprioceptor, or what we will simply call the postural nerves. These nerves are responsible for sending information to the brain about where your body is and what it’s doing. For example, if you close your eyes and hold your arm out to your side, you can tell exactly where your arm is even though you can’t see it because the postural nerves of the arm and upper back tell the brain where your arm is. Many people have discovered what happens when their postural nerves aren’t working correctly after they have had too much alcohol to drink. Alcohol partially disrupts your postural nerves, making it difficult to touch your finger to your nose when your eyes are closed, or walk a straight line with your eyes open.

In the next section, we will be pulling all of this information on bones, joints, muscles and nerves together in a discussion about body mechanics.

The Four Pillars of Body Mechanics

As we have discussed in the previous sections of this post, the human body is an amazingly complex system of bones, joints, muscles and nerves, designed to work together to accomplish one thing: movement. Everything about the human body is designed with movement in mind – nerve fibers stimulate the muscles to contract, muscles contract to move the bones, bones move around joints, and the nervous system controls it all.

In fact, research has shown that movement is so critical to our body’s health that a lack of movement has a detrimental affect on everything from digestion, to our emotional state, immune function, our ability to concentrate, how well we sleep and even how long we live. The bottom line is that if your lifestyle does not include enough movement, your body cannot function efficiently. Consequently, three things will happen: first, you will not be as physically healthy and will suffer from a wide variety of physical ailments, ranging from headaches to high blood pressure. Second, you will not be as productive in your life because of reduced energy levels and the ability to mentally focus. Third, because you have less energy, your activity level will tend to drop off even further over time, creating a downward spiral of reduced energy and less activity until you get to a point where even the demands of a sedentary job leave you physically exhausted by the end of the day.

Pillar One: Posture

The ancient Japanese art form of growing Bonsai trees is fascinating. Bonsai trees are essentially normal trees that have been consistently stressed in a particular way for a long time to create a posture which would never be found in nature.  Depending on how the tree is stressed while it grows, it may end up looking like a miniature version of a full-sized tree, or it may end up looking like a wild tangle of branches with twists and loops. Every day in our practice, we see the human equivalent of Bonsai trees walk through our door – people with an unnatural posture due to the continual daily stresses on their body.

The most immediate problem with poor posture is that it creates a lot of chronic muscle tension as the weight of the head and upper body has to be supported by the muscles instead of the bones. This effect becomes more pronounced the further your posture deviates from your Structural Center.

To illustrate this idea further, think about carrying a briefcase.  If you had to carry your briefcase with your arms outstretched in front of you, it would not take long before the muscles of your arms and shoulders would be completely exhausted. This is because carrying the briefcase far away from your Structural Center places undue stress on your shoulder muscles. If you held the same briefcase down at your side, your muscles would not fatigue as quickly because the briefcase is closer to your Structural Center and the weight is, therefore, supported by the bones of the skeleton, rather than the muscles.  

In some parts of the world, women can carry big pots full of water from distant water sources back to their homes. They are able to carry these heavy pots a long distance without significant effort because they balance them on the top of their heads, thereby carrying them at their Structural Center and allowing the strength of their skeleton to bear the weight, rather than their muscles.

Correcting bad posture and the physical problems that result are accomplished by doing two things. The first is to eliminate as much ‘bad’ stress from your body as possible. Bad stress includes all the factors, habits or stressors that cause your body to deviate from your Structural Center. This can include a poorly adjusted workstation at work, not having your seat adjusted correctly in your car, or even carrying too much weight around in a heavy purse or backpack.

The second is to apply ‘good’ stress on the body in an effort to move your posture back toward your Structural Center.  Getting your body back to its Structural Center by improving your posture is critically important to improving how you feel.  This is accomplished through a series of exercises, stretches and changes to your physical environment that all work to help correct your posture.

Pillar Two: Mobility

Imagine waking up one morning with a frozen shoulder where you couldn’t move your upper arm more than a few inches in any direction. How much would that impact your ability to do your job? How much would that affect your ability to drive your car or even to dress yourself? How much would that affect your ability to concentrate on anything other than your shoulder?  Obviously, if your shoulder did not move correctly, it would have a dramatic impact on your life. Well, the same is true with mobility in every part of your body. If things aren’t moving the way they are supposed to move, it will have a negative impact on your ability to function at work, take care of the demands of everyday life and even your ability to concentrate.

Each year, we have had a number of patients come into our clinics with severe low back pain who stated that their pain came on suddenly when they did something as simple as bend down to pet their cat, put on their socks, or pick up the newspaper.  Just about everyone would agree that a person’s body should be able to handle something as simple as bending over to pick up a newspaper or putting on their socks, right? So what happened?

In every one of these cases, we found that many of the joints in their body were barely moving at all; they were ‘all locked up.’  When the joints in one area of the body do not move the way they should, other areas of the body are forced to move more than they were designed to in an effort to compensate for the area that is not moving. This creates a significant stress on the areas that have to pick up the slack of the joints that aren’t moving so well. This soon leads to pain and inflammation. At the same time, the areas that don’t have normal movement will slowly worsen as the muscles continue to tighten; The joints stick together and the ligaments and tendons shorten. This leaves the body in a very unstable condition and if left unchecked, this process will continue until the body can hardly move at all and the person suffers flare-ups of pain at the slightest provocation. 

Most of us have seen people who have lost most of their normal mobility; they look like their whole body has been starched stiff whenever they try to move around. This is especially prevalent among the elderly. Contrary to popular belief, this is not the inevitable effect of aging, rather it is the inevitable effect of not maintaining the body’s mobility through exercise, stretching and chiropractic care. There are a lot of people in their 60s, 70s or even older, who are stronger and more flexible than the average person in their 30s simply because they keep themselves exercising. Maintaining mobility is critical in order to live free from pain and disability. Maintaining good mobility is not difficult, but it does not happen on its own.

Just as in developing a good posture, it is necessary that you perform specific exercises and stretches to keep your muscles, ligaments and tendons flexible and healthy. In addition, it is necessary that all of the joints in your body are kept moving correctly as well. Although this can be achieved to a great degree through the exercises and stretches in this book, most people also find routine chiropractic care to be very beneficial.

Pillar Three: Strength

Strong muscles keep your body upright and allow you to move. Good muscle strength and balance are critical for proper posture and to minimize muscle tension. Your muscles function much like the wires that hold up a tall radio or television antenna.  If the wires are equally strong on all sides, the antenna will stand up straight. If one of the wires becomes weak or breaks, the antenna will either lean to the side or collapse. The same is true with your body. If the muscles on all sides of your spine are balanced and strong, your body will stand up straight and strong. Unfortunately, most people don’t have balanced and strong muscles. The reason for this gets back to exercise.

Muscles are very efficient at getting stronger or weaker in response to the demands placed on them. Since most of us sit at a desk, drive a car and sit on the sofa at home, many of our muscles are not challenged. Consequently, they become weak. At the same time, the muscles that are constantly used throughout the day become strong. This imbalance of muscle strength contributes to poor posture and chronic muscle tension.  Left unchecked, muscle imbalances tend to get worse, not better, because of a phenomenon called “Reciprocal Inhibition.”

Reciprocal Inhibition literally means “shutting down the opposite.” Simply put, for all of the muscles that move your body in one direction, there are opposing muscles that move the body in the opposite direction. In order to keep these muscles from working against each other, when the body contracts one muscle group, it forces the opposing group to relax – it shuts down the opposite muscles.

This phenomenon is especially important to people who work at a desk, because all day long the same muscles in the upper back and chest area of the body are used. This means that all day long the body is essentially shutting down the opposite muscles in the middle back. Over time, the muscles in the middle back become very weak because they are not being worked like the muscles in the front.  This contributes to poor posture and chronic muscle spasms and pain.

The easiest way to correct this imbalance is to do specific exercises which will increase the strength of the back muscles, along with trigger point therapy and chiropractic care. Once the muscles in your middle back are strong, the tightness and poor posture simply disappear.

Pillar Four: Coordination

Michael was a powerlifter who was suffering from shoulder pain. We took x-rays, did all of the usual tests in an attempt to figure out what was wrong with his shoulders, but everything turned up normal. He was young, healthy, had incredible strength, great flexibility and no specific injury to the shoulders.
Since the shoulder is a very mobile and unstable joint, we knew that if all of its muscles were not contracting in the correct order or with the right amount of tension, the result would be increased mechanical stress of the shoulder joint, ultimately resulting in pain.

We prescribed a series of very simple, lightweight exercises for him to do on a daily basis for the purpose of re-establishing normal shoulder coordination. The results were immediate and profound. Not only did his pain completely disappear, but his ability to bench press improved.  It turned out that Michael’s only problem was that his muscles were not coordinated correctly. Although posture, joint mobility and muscle strength are all important, they are not the whole story. We also must have coordinated control over our muscles and joints if we want to enjoy good body mechanics.

Healthy coordination is simply the result of using the body in the manner in which it was designed. Exercises such as walking, swimming, climbing, yoga, aerobics, bicycling, martial arts and body building all help to improve muscle coordination, whereas working at a desk, reading and watching television do the opposite. Without realizing it, most people are in a dramatic state of muscle incoordination. This occurs simply because they sit for many hours every day and do not perform exercises on a regular basis that will work to keep all of the muscles in their body properly coordinated. This muscular incoordination contributes to muscle tightness, restricted movement and joint pain.

The Mechanics of Your Spine

Now that you know on all of the major aspects of body mechanics and you understand why it is so important that the skeletal system, muscular system and nervous system work together in a tightly coordinated way, let’s take a look at the single most complex and important system of bones, muscles
and nerves in your body – your spine.

Your spine is one of the most complex systems in the body, consisting of nearly a hundred intricate joints and trillions of nerve pathways connected together by a complicated meshwork of ligaments, tendons, cartilage and muscles. The spine is designed to do three things simultaneously:

1) to protect the spinal cord that serves as the primary communication conduit between your brain and the rest of your body;
2) to serve as a structural support upon which all of your organs and upper body /rave to rest; and
3) to provide an incredible amount of mobility and flexibility, allowing you 10 bend forward to touch your toes, swim, throw a baseball and turn your head.

Unfortunately, with this degree of mobility and flexibility come instability and the susceptibility to injury. In order to function correctly, all of the bones, joints, muscles and nerves have to work in perfect coordination to maintain your proper posture, strength and movement. A disruption in the position or movement in any one of the bones of the spine or a loss of muscle balance or coordination will impose a significant stress on the spine.

Fortunately, most of us don’t experience severe problems with our spine or spinal cord, but small problems occur all the time. These happen when we slip and fall, are in a car accident, sleep in a strange bed, sit with poor posture, “throw our back out,” or lift something incorrectly. It’s typically not just injury to the bones and joints themselves that causes misalignment in the spine. Damage to the muscles and connective tissue are just as important, for these are the structures that are responsible for supporting the bones and joints. Once these tissues are damaged, the vertebrae can lose their correct alignment or movement. When this happens, it not only can cause pain and loss of function in the back, but also can affect other areas of the body.

Let’s review the basic construction of the spine. The spine is made up of a stacked set of bones called the vertebrae. These are like the bricks upon which our entire structure is built.  Each vertebra consists of a vertebral body, which is a large oval-shaped solid block of bone, and a vertebral arch, which is located on the back of the vertebral body and creates the space through which the spinal cord runs.

Each vertebra is attached to two adjacent spinal vertebrae, with a disc between them. These discs, technically called inter-vertebral discs, are thick pads of fibrocartilage that act as shock absorbers and give the spine its ability to Hex and twist. The disc itself is kind of like a jelly donut. It has an outer Fibrous portion called the annulus, and a soft jelly-like center called the nucleus pulposus. A disc herniation occurs when the fibers in one portion of the annulus are torn, allowing the nucleus
pulposus to partially push through the annulus, creating a bulge in the outer disc; much like a tire develops a bulge when there is a break in one of the underlying supporting fibers. Disc bulges do not always lead to pain, but quite often they do. The pain may come from the irritation of the nerves within the disc itself, or it may be caused by the disc bulge impinging upon a nerve that runs through the area. As we age, our discs tend to dehydrate and break down. This process is accelerated by smoking and not keeping yourself fully hydrated, as well as by a sedentary lifestyle.

Between each pair of vertebrae and behind the disc is a small space where the nerves exit from the spinal cord and run to all of the areas of the body. This space is called a vertebral foramen. Foramen is an impressive medical term that simply means “hole.”  Vertebral foramina (holes) can become compressed when a disc bulge presses into the area, inflammation causes the tissues in the area to swell or if the intervertebral disc becomes dehydrated. When this happens, excruciating pain can result, which may radiate to other areas of the body.

Ligaments bind the vertebrae together and tendons attach numerous muscles to each segment. These ligaments and tendons help absorb shock and restrict how much movement there is between each set of spinal vertebrae. Unfortunately, these ligaments and tendons can be damaged whenever spinal vertebrae are forcefully moved beyond their normal limits- such as in a whiplash or sports injury. An injury to a ligament is called a sprain. If the injury is to the tendon or muscle, it is referred to as a strain.

Muscles attach to the bony extensions of the vertebrae and provide movement in the spine by contracting in a highly coordinated way. Like ligaments, muscles are important for absorbing shock and releasing it in a controlled way. For example, when your heel strikes the ground as you walk it is your muscles that lessen the shock before it reaches your head so that your teeth don’t clatter together each time you take a step.

As a whole, the spine forms the protective housing for the spinal cord, which begins at the brain stem (back of the skull) and extends like a wire down the length of the spine. Ultimately, the spinal cord sends out nerve branches that send and receive signals from every cell in the body. The close relationship between the spine and the spinal cord means that damage to any of the discs or vertebrae can also affect the spinal cord or the nerves associated with it, causing pain or abnormal function of the structures innervated by the affected area.

The spine is divided into four different regions. The upper seven vertebrae in the neck are collectively called the “cervical spine,” with the skull sitting directly upon the first cervical vertebra (also called the Atlas). The middle twelve vertebrae are called the “thoracic vertebrae.” All of the thoracic vertebrae have a pair of ribs attached to them. The twelve pairs of ribs are important for protecting several of your internal organs and are critical for breathing. The lower five vertebrae are referred to as the “lumbar vertebrae” and because they bear the full weight of your upper body, are the most frequently injured. The lowest region of the spine is called the sacrum (tailbone). As a child the sacrum is made up of five vertebrae, just like the lumbar spine.  During later childhood, these five vertebrae fuse together to make one solid bone called the sacrum. Technically speaking, kids have six more bones in their spine than adults to.

When viewed from the front or back, the spine should appear perfectly straight and symmetrical, reflecting the fact that your body is also symmetrical when viewed from the front or back. When viewed from the side, however, four major curves should be seen – one in each of the cervical, thoracic, lumbar and sacral regions. In both the cervical and lumbar regions of the spine, the curves bend backward. These are called “lordotic” curves. The curves in the thoracic and sacral regions bend forward. These are called “kyphotic” curves. As strange as it may seem, these curves actually add a considerable amount of strength and resiliency to the spine. Think about the curves as being like a spring, allowing the spine to flex and absorb shock much better than if it were straight. In fact, when a region of the spine loses its normal curve, as often happens in the neck following a whiplash injury, the discs that separate the vertebrae begin to degenerate.

Because of the complexity and instability of the spine and its potential for affecting so many systems in the body, this is the structure that chiropractors end up working on more than anything else. Problems in the spine can come from a variety of sources:

• Discs can become herniated and compress nerves that go to the legs or arms
• The joints between the vertebrae may become stuck
• The bones, ligaments or joints themselves may be injured
• The disc space itself can be a source of pain
• The muscles surrounding the spine may become injured
• Muscle spasms may develop due to overuse or injury
• Inflammation from overuse, injury or disease may irritate the spine

Each of these problems needs to be identified and properly treated in order for you to enjoy the degree of optimal health of which your body is capable.  Just ‘cracking’ your back is not enough.

Quick Review

We covered a whole lot of information in this post.  Let’s review quickly before moving on. We discussed the four components of the neuromusculoskeletal system; the bones and joints which serve as the framework for the body, the muscles which are responsible for movement and the nervous system which is responsible for controlling it all. We discussed the Four Pillars of Body Mechanics – posture, mobility, strength and coordination – and why each of these are important.

You learned that when your posture deviates from your Structural Center, your muscles tighten up, resulting in pain and decreased mobility. You learned that once you begin to lose mobility, it usually continues to worsen unless you perform specific exercises and stretches to re-establish normal motion. You learned that muscles will either become stronger or weaker depending on how much they get used and that muscular imbalances will often lead to chronic muscle spasms and pain.  You learned about the important role of coordination in achieving good body mechanics.

Finally, you learned that the main connection from the brain to the rest of the body is the spinal cord. Your spine is an incredibly complex and important structure for your overall health due to its close relationship to the spinal cord and nerves.  If the spine is healthy, then the central nervous system has the means by which to communicate and coordinate all of the body’s functions. But if there is any misalignment, impingement or interference with this communication, then pain and disability result.