The Anatomy of Low Back Pain

Understanding the anatomy of the lumbar spine is key to understanding and managing low back pain.

The lumbar spine, commonly called the “low back”, consists of 5 vertebrae, and is located between the thoracic spine (which articulate with ribs) and the sacrum. The vertebrae themselves are given numbers by which they are identified, for example – Lumbar Vertebra 1 = L1, Lumbar Vertebra 2 = L2 and so on.

The normal lordotic curve of the low back is known as a secondary curve, and starts to develop in infancy due to weight bearing caused by learning to sit up and walk.  The low back is especially vulnerable to injury due to its weight bearing task and mobility.

Between each vertebrae throughout the whole spine (except for C1 and C2) is a intervertebral or fibrous disc. The purpose of the disc is to provide cushioning and shock absorption from weight bearing and movement. The intervertebral disc is comprised of the annulous fibrosis and the gel-like centre called the nucleus pulposus – these structures are work together to provide the shock absorption, and are both implicated in disc dysfunction and neurological symptoms.

Facet joints are the articulating surfaces of bone between vertebrae. These synovial joints are known as “plane” joints because their flat surfaces glide over each other. These joints may become inflamed due to injury to the joint or joint capsule itself, or due to compression of the intervertebral discs, forcing them to interact in a “close-packed” position. This close packed position means that the joint surfaces are forced closer together than normal, and will irritate the bone and cartilage during movement as they contact each other and create friction.

During an acute injury, the inflamed tissue in the joints may irritate the nerve roots as they exit the spinal cord via the intervertebral foramina. Eventually, if facet irritation is untreated, bony spurs may develop due to chronic inflammation and cause spinal stenosis – a decrease in the size of the “vertebral foramen” or spinal canal.

In the case of a “bulging” or herniated disc, pressure is exerted on the nerve root as it leaves the spinal cord via the intervertebral foramina. This pinching or pressure on the nerve root will cause sharp, shooting pain, especially when the patient leans forward (flexes) from the hip.  Symptoms will present in the areas that the compromised nerves supply.

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What are the Causes of Low Back Pain

Low back pain is one of the most common conditions treated by massage therapists. I have been asked by countless clients “what are the causes of low back pain?”, and I am afraid to say that there is no simple answer. The causes of low back pain are many, and it is important for clients to understand this, as appropriate treatment approaches differ as much as the causes themselves.

So common is low back pain that I decided to do a little research and try to get some statistics on it.

Here is what I found:

Back pain statistics from the Workers Compensation Board of British Columbia

From 2000 to 2004 WorkSafeBC (Workers’ Compensation Board) received over 107,000 claims for back strains

back strains account for just over 25% of all WorkSafeBC (Workers’ Compensation Board) claims.

Roughly 30% to 40% of all workplace absences in Canada are due to back pain

injuries may be caused by a single instance of overexertion or develop as a result of repeated motion over time.

Over two-thirds of back injuries are a result of overexertion

60% to 90% of the population will experience low back pain in their lifetime

More than 90% of low back pain cases have no specific cause (such as infection, osteoporosis, arthritis, etc.). In these cases the pain will usually subside without treatment in four to six weeks.

In the health care industry, injuries due to patient handling (lifting, transferring, or repositioning) account for about 35% of all accepted time loss claims and for about 40% of claim costs.

So, that’s all fine and well, but while “back strain” appears to be the most common cause of low back pain, and quite a generic term, there are other causes of low back pain. It is very important to identify the cause and contributing factors to low back pain for successful treatment, otherwise clients may just end up wasting time and money.

Falling into each of these 4 broad categories, which I am going to name as causes for low back pain, are several different conditions which I have seen in my practice.

Low back pain cause – Muscle fatigue or strain

Also referred to as a “pulled muscle”, this happens when muscles are overused or is weak. Muscles can also be torn from an injury, and of course, the more serious the damage, the longer it will take to heal …

This is also the primary participant in “soft tissue injuries” – the effects of which insurance companies have lead people to believe are minimal. The reality is that soft tissue injury, and the chronic inflammation which may accompany the more severe injuries, often take longer to heal than the ballpark figure in the insurance tables. However, I digress …

Pain can also be caused by an imbalance of muscle development, or a lack of “extensibility” or “stretch” of the muscles. This is very easy to see, for example, in athletes who may overuse and overdevelop one muscle group. This muscle imbalance is stressful for the body and may cause pain and spasm in the opposing muscle group as the body tries to maintain homeostasis. This lack of balance can lead to “mechanical dysfunction” of the joints of the back (see below). Muscle imbalance, can, however, be treated at home if you know what to do.

Low back pain cause – Joint and bone dysfunction

This type of back pain is often referred to as “mechanical back pain” or “mechanical joint dysfunction” when referring specifically to the joints. What this means is that a joint is not able to move as it is meant to, either from injury to the bone or joint, or hypertonicity of the surrounding muscles (hyper meaning ‘too much’, tone means the amount of tension in the muscle). Unfortunately, this can lead to several other issues and can be a self-perpetuating cycle if left untreated, often causing seemingly unrelated problems.

Of course, bones and joints can also be affected by fractures, breaks, arthritis and a multitude of other conditions which is well beyond the scope of massage therapy to diagnose and in some cases, treat. Massage therapy can, however, be used to alleviate symptoms and assist in recovery.

Low back pain cause – neurological

Low back pain from a neurological source can be a result of a variety of triggers, all of which are related to either the intervertebral disc, spinal cord, or the “nerve roots” as they exit the spinal cord. This type of pain can be excruciating and very debilitating, as anyone with a “slipped disc” will tell you. (this is a bit of a misnomer, and will be addressed in upcoming articles). This type of low back pain usually presents as symptoms in the area which the affected nerve root supplies, so the location of the symptoms is really dependent on the nerve root “level” where the injury or restriction happened. (and often the level of the injury is determined by the presentation of symptoms.) Pain which occurs in one area but originates from dysfunction in another area is called “referred” or “referral” pain.

Low Back Pain – Neurological from Bulging, or Herniated, Disc

Low back pain cause – visceral referral

In some cases pain can be a result of a dysfunction or infection of an internal organ. This happens because the “nociceptors” (pain receptors) of an organ are irritated and the pain is either felt in the skin or tissue which is superficial to (or just above) the organ, or in a classic “referral pattern”. Pain caused by visceral dysfunction can be quite severe.  A classic example is low back pain in the lumbar area which may wrap around a persons front, or extend down the sides of the thighs and into the groin.  This is a referral pattern of the kidneys, and should never be ignored.

Remember, most low back pain is a result of muscle weakness or imbalance. However, if you are not aware of any activity or cause of the pain, the pain is severe, or if the pain has been present for any length of time, I would urge you to see a physician immediately to rule out anything more serious than a muscular cause for the pain. You may also want to check out more information I have found on WebMD.

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Thoracic Outlet Syndrome Types, Causes and Symptoms

What is thoracic outlet syndrome, what causes it, and what are the symptoms?

Thoracic Outlet Syndrome, also known as TOS, is a compression of the brachial plexus and subclavian artery and vein. The brachial plexus supplies the upper limb with both sensory and motor nerve fibres, and the subclavian artery supplies the blood supply. There are four areas where the plexus and artery may be compressed and in each instance, the symptoms will present differently.

The part of the brachial plexus most likely to be affected is the medial cord, which orginates from nerve roots C8 to T1.

Symptoms of Thoracic Outlet Syndrome:

Due to involvement of the medial cord of the brachial plexus, the ulnar nerve is most impacted by this compression syndrome. Muscles affected will be the Flexor Carpi Ulnaris, the ulnar aspect of the Flexor Digitorum Profundus, as well as most intrinsic (small) muscles of the hand. As a result, there will be some weakness or altered sensation on the ulnar aspect of the forearm, the hand and little finger. Signs and symptoms will vary, however, depending on the location of the compression and the structure involved.

Compression of a nerve will result in pain, loss of sensation and in chronic cases, muscle wasting or weakness. (this is known as denervation atrophy) Compression of blood vessels (subclavian or axillary arteries, depending on site of compression), will result in pain, paleness of the skin supplied by the artery, possible cyanosis (blue coloring) and decreased skin temperature. Prolonged decrease of blood supply can result in trophic skin changes, emboli (blood clots) and gangrene. Compression of a vein will result in edema, and the blood is unable to be carried back to the heart and lungs.

There are 4 main areas where compression may occur

1) The anterior and middle scalene, a.k.a. the interscalene triangle. The brachial plexus and subclavian artery pass through here, but it is the medial cord of the plexus, arising from the C8-T1 nerve roots, which is most likely to be affected. (*note: the scalenes are classified as secondary muscles of respiration because they attach to the ribs and contract during respiration)

2) Pectoralis minor – compression will occur between the pectoralis minor and its insertion on the coracoid process of the scapula. A person who presents with hyperkyphosis (rounded, slumped shoulders) may be more inclined to have compression here, especially when the muscle is stretched (for example, when they straighten up). The pectoralis minor, by attaching on ribs 1-8, may be affected by any respiratory disorder, leading to hypertonicity of the muscle and subsequent compression of the subclavian artery as it becomes the axillary artery when it passes deep to the clavicle.

3) Costoclavicular – compression occurs between the 1st rib and the clavicle. This is most likely to be a result of injury to the clavicle, such as a break or dislocation, and is prone to affect the vasculature (as the axillary vein becomes the subclavian vein)

4) Presence of a cervical rib - the presence of an extra rib is determined by an x-ray, and it interferes with the size of the interscalene triangle, therefore allowing less room for the plexus and vasculature.

The borders of the thoracic outlet are:

posteriorly (the back) the body of vertebrae T1 laterally the 1st rib bilaterally
anteriorly – manubrium of the sternum

Structures passing through the Thoracic Outlet
The brachial plexus, subclavian arteries and veins.The muscles involved in this syndrome are the anterior and middle scalenes, pectoralis minor and the subclavius.

Who is at risk for Thoracic Outlet Syndrome?

Thoracic Outlet Sydrome usually affects people whose posture tends to be very forward and slumping. Think of a person who sits at a desk all day, or who does a lot of work moving forward (or a massage therapist!). Others at risk may also have “military posture”, extreme retraction of the shoulders which pulls the pectorialis minor tight over the plexus and artery, thus compressing it. Also at risk are people who have had a broken or dislocated clavicle, especially those with a more complicated or compounded break. Due to the attachment of the scalenes and pectoralis minor on the ribs, people who have a respiratory disorder and difficulty breathing often recruit these muscles, thus increasing the incidence of hypertonicity, and the presence of myofascial trigger points.

Thoracic Outlet Syndrome or Raynaud’s Disease?

The therapist, during the course of performing orthopedic tests for TOS, will look for a positive test of a decreased or absent pulse, as well as numbness and tingling or fatigue in the ulnar distribution of the forearm and hand. Raynaud’s Disease presents similarly, but is a peripheral vascular disorder which occurs due to vasospasm and results in decreased circulation. For Raynaud’s disease to be diagnosed, it must be followed closely by a physician for 2 years and manifest as decreased circulation and increased sensitivity of the arms and hands.

How can massage therapy be used to treat Thoracic Outlet Syndrome?

Massage therapy can provide valuable assistance to someone suffering from TOS, either as a stand-alone treatment, or in conjunction with other modalities (i.e. physiotherapy or chiropractic).
Wherever the location of compression, the therapist will attempt to decrease hypertonicity and myofascial trigger points of the involved muscles as well as stretching. Manual lymph drainage can assist in the reduction of fluid build up post treatment. It will also be necessary to retrain the client concerning proper posture.After the treatment plan concludes, it would be wise to encourage the client to continue stretching, and also to schedule maintenance appointments to prevent a relapse.

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