What Causes Back Pain?
Written by Dr. Jesse J. Suess, DC
It is estimated that over 100 million Americans suffer from some sort of back pain throughout the calendar year, which equates to over $600 billion per year in health care costs and lost productivity according to a report by the Institute of Medicine (IOM). In layman’s terms that is suggesting that you have a 1 in 3 chance of suffering from back pain in the next year. Back pain can be one of the most confusing and frustrating ailments to treat, and the reason being is that there are so many different potential pain generators throughout the back, neck, and spine. In this article I will dive into several different common causes of back pain.
Now it is important to mention that this article is written to educate you, the patient, on common causes of low back pain and commonly presented symptomology. This article is not intended for you to self-diagnose. In order to get a full an adequate diagnosis, I strongly suggest that you seek the opinion of someone who is an expert in the field of back pain, such as a Doctor of Chiropractic.
What is “the back”?
This is a relatively simple question, with a very complex answer. When I refer to “the back” I am speaking of the 5 areas of the spine (cervical, thoracic, lumbar, sacrum, and pelvis) as well as the different muscles, ligaments, and motion segments (joints) that are associated with the spine. There are 33 vertebrae in the human spine (7 Cervical, 12 Thoracic, 5 Lumbar, 5 sacral segments, and 4 coccygeal segments). So when I am referring to the back I am referring to the lowest portion of the pelvis all the way up to the base of the skull.
Listed below are 5 of the most common anatomical and physiological pain generators throughout the spine, listed in no particular order.
Muscular Strain
One of the more common causes of acute low back presentation is the muscular system. As we know, muscles attach to bones. The main job of a muscle is to move a bone, and it accomplishes this goal by shortening and elongating. Most of the muscles of the back find their origin or insertion on specific vertebral segments. Muscles also have a very rich blood supply, which allows them to receive the proper nutrition to heal rather quickly. When a muscle is irritated, by either over exertion or repetitive strain, it reacts in a very unique way. For example, a traumatic injury to a muscle such as over exerting yourself on the squat rack at the gym, can lead to a tear of the muscle fibers. And as a consequence, the muscle is not able to do its job and fully shorten because the muscle fibers themselves are no longer intact. This type of injury is usually associated with a particular “ouch moment” and is usually accompanied by a good degree of swelling and possibly bruising in the area of pain. The pain is usually localized to a particular area and is usually accompanied with palpable tenderness in the area of pain.
Another example of muscular related back pain would be repetitive strain type injury. Repetitive strain can be linked to poor ergonomics or posture, and has quite a different presentation than a traumatic or acute type injury described above. When we are dealing with repetitive type injuries we are most often dealing with pain that has been manifesting itself over a period of time, also known as “chronic pain”. The muscle itself reacts to chronic pain by getting stuck in the shortened position. This often causes a buildup of muscular waste (or lactic acid) in the area, which in turn forms what are known as “trigger points” in the muscle. Because the muscles are stuck in the shortened position, the muscle begins to lose access to some of it's abundant blood supply, the muscle in return becomes much weaker. The pain presentation with this type of is a generalized “dull/achy” presentation that gets worse as the day progresses. This type of chronic presentation is usually not accompanied by a particular “ouch moment”, and is usually of unknown origin.
Ligamentous Sprain
Although ligaments and muscles are commonly thought about as closely related, they actually function quite differently. The function of the ligament is to hold the bones together and guard against hyperextension or hyperflexion of the joint. In other words, the job of the ligament is to make sure that a joint does not exceed its natural range of motion. Another unique quality of a ligament is its lack of elasticity. Think of a muscle as a rubber band, it has high elasticity and when stretched can easily mold itself back to its initial starting point. Now think of a ligament as a piece of saltwater taffy, or for the younger generation, an “airhead” (yes the candy). Initially taffy is really tough to stretch, but when you exceed the candy's elastic barrier and are finally able to stretch the taffy (or sprain a ligament) the taffy is not very elastic and does not mold back to its initial form. The reasoning behind this is because unlike it’s muscular counterpart, the ligament has a very poor blood supply. So ligamentous injuries often take longer to heal.
Each vertebral motion segment has several different ligaments in place in order to “check” the motion of the segments and avoid hypermobility. A well-known ligamentous injury is “whiplash” type injuries.
Commonly presenting symptoms of ligamentous injury is a feeling of instability in the area. The pain is often provoked by an “ouch moment” such as a bad car accident or hard fall, but doesn’t necessarily have to be associated with trauma. The pain is commonly described as a “deep and achy” pain that is localized in nature.
The Facet Joint
The facet joint, also known as the zygapophyseal joint, is one of the most overlooked pain generators throughout the spine. The facet joints are joints located on the posterior (or back) side of the spine. Each particular vertebra has two superior facets and two inferior facets that help it attach to the adjacent vertebrae and form a motion segment. What makes the Facet joint unique is that the nerve roots exit the spinal column directly adjacent to the facet joints.
Unlike the popular intervertebral disc, the facet joint is a synovial (or fluid-filled) joint which makes it similar to most other joints in your body such as the knee, shoulder, elbow, wrist, etc. Surrounding each facet joint is a “capsule” that encases the joint fluid. When the facet joint gets irritated the joint capsule tends to “swell”, very similar to how your knee or your ankle swell when you sprain those joints. This joint is commonly injured in chronic situations, when the segments are “stuck” or “locked” in a certain position over a period of time; which triggers the body’s inflammatory response, which in turn causes the joint capsule surrounding the joint to swell and irritate the adjacent nerve root.
A common presentation for this type of injury is either low back or neck pain that is localized in nature. The pain is usually provoked by certain motions, most commonly extension (bending or looking backwards). The pain can be, but is usually not associated with an “ouch moment” and is commonly involved in the chronic presentation of back pain.
The Intervertebral Disc
The intervertebral disc (or IVD) is by far the most famous joint in the spine. Each vertebral segment has two associated IVDs associated with their superior and inferior endplates, respectively. The IVD is a unique type of joint in the body because it is not considered synovial (fluid-filled), in fact the IVD is considered a fibro-cartilaginous joint. The analogy that is often used to describe the disc is a jelly donut. Much like a jelly donut, the Intervertebral disc has hard outer fibers, called annular fibers, which encase the “jelly-like” fluid in the center. As stress and strain is put on the IVD, the joint fluid begins to poke-out, or “bulge”, out of the external surface. This “bulge” can become a pain generator if it begins to push on the surrounding structures such as the spinal cord (known as spinal stenosis), or the nerve root (a common cause of sciatica).
There are different stages of disc injury such as disc bulge, disc herniation, or disc protrusion/rupture; from least severe to most. Each of them have much different presenting symptoms. I plan on “Debunking the disc” in a future article, so for now we will talk about the most common presenting symptoms with a presenting disc issue.
The patient usually presents in what we call an “antalgic posture”, usually leaning down and away from the area of complaint. It is also common that the patient reports associated numbness or tingling with “radiating” or “shooting” pain into the extremities (i.e. Sciatica). This situation can be caused by both acute and chronic situations, so it’s hard to say whether a particular “ouch moment” is associated with this type of injury.
The Sacroiliac Joint
The Sacroiliac (or SI joint) is a major weight-bearing joint in the body, and can be a big-time player in low back pain. The SI joint is located where the pelvis (or ilium) meets the sacrum, hence the name “Sacroiliac Joint”. The sacroiliac joint is a very unique joint because only the upper 1/3 of the joint is mobile. When this joint is fixated, it is often accompanied by some degree of pelvic rotation. We can often see pelvic rotation through leg length. The hip joints are attached to the pelvis, and when the pelvis rotates it naturally takes the hip joints with it and causes what we refer to as a “functional short leg”. This type of short leg is by no means a permanent condition, and is often the result of muscular imbalances due to the imminent pelvic rotation.
Patients who present with a problem with the SI joint often present with a localized pain near the dimples of the back. When you touch your low back you will feel two “bumps” on each side of your low back, the SI joint is located just below these bumps called the PSIS. The patient also often notes pain while bending forward and can feel pain while walking or sitting as well. The pain is not commonly associated with an “ouch moment”, and can be accompanied by some degree of tingling and radiating pain into the lower extremities, depending on the complexity of the situation.
It is important to realize that these are some of the most common mechanical pain generators throughout the spine, and that this article is meant for educational purposes. There are many other causes of back pain. Again, if you are experiencing any sort of pain in the back or neck we strongly suggest that you seek expert care from somebody who spends all day treating and diagnosing different ailments that affect the spine and its supporting structures. If you have any comments, questions, suggestions, please feel free to contact me directly. All contact information can be found on my website. If you are interested in weekly health tips via e-mail, please leave your information in our sing-up form below.
Yours in Health,
Dr. Jesse J. Suess, DC
Suess Family Chiropractic, LLC
22 Wyckoff Ave., Suite 1
Waldwick, NJ 07463
References:
Institute of Medicine: "Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education and Research."