Your backbone, or spine, is made up of 26 bone discs called vertebrae. The vertebrae protect your spinal cord and allow you to stand and bend. A number of problems can change the structure of the spine or damage the vertebrae and surrounding tissue.

They include:

• Infections
• Injuries
• Tumors
• Conditions, such as ankylosing spondylitis and scoliosis
• Bone changes that come with age, such as spinal stenosis and herniated disks

Spinal diseases often cause pain when bone changes put pressure on the spinal cord or nerves. They can also limit movement. Treatments differ by disease, but sometimes they include back braces and surgery.

Ankylosing spondylitis is a form of painful, ongoing joint inflammation (chronic inflammatory arthritis) that primarily affects the spine. Early symptoms of ankylosing spondylitis typically begin between the ages of 15 and 30. Most commonly, affected individuals first experience chronic back pain and stiffness. This pain worsens with rest or inactivity, and tends to be relieved with physical activity or exercise.

Pain in ankylosing spondylitis results from inflammation of the joints between the pelvic bones (the ilia) and the base of the spine (the sacrum). These joints are called sacroiliac joints, and inflammation of these joints is known as sacroiliitis. The inflammation gradually spreads to the joints between the vertebrae, eventually involving the whole spine, causing a condition called spondylitis. Over time, back movement gradually becomes limited as the bones of the spine (vertebrae) fuse together. This progressive bony fusion is called ankylosis. These fused bones are prone to fracture.

Ankylosing spondylitis can involve other joints as well, including the shoulders, hips, and, less often, the knees. As the disease progresses, it can affect the joints between the spine and ribs, restricting movement of the chest and making it difficult to breathe deeply.

Ankylosing spondylitis affects the eyes in more than 30 percent of cases, leading to episodes of eye inflammation called acute iritis. Acute iritis typically affects one eye at a time and causes eye pain and increased sensitivity to light (photophobia). Rarely, ankylosing spondylitis can also cause serious complications involving the heart, lungs, and nervous system. Six to 10 percent of people with ankylosing spondylitis have additional inflammatory disorders such as psoriasis, which affects the skin, or ulcerative colitis or Crohn's disease, which both affect the digestive tract.

If you have had lower back pain, you are not alone. Back pain is one of most common reasons people see a doctor or miss days at work. Even school-age children can have back pain.

Back pain can range in intensity from a dull, constant ache to a sudden, sharp or shooting pain. It can begin suddenly as a result of an accident or by lifting something heavy, or it can develop over time as we age. Getting too little exercise followed by a strenuous workout also can cause back pain.

There are two types of back pain:

• Acute, or short-term back pain lasts a few days to a few weeks. Most low back pain is acute. It tends to resolve on its own within a few days with self-care and there is no residual loss of function. In some cases a few months are required for the symptoms to disappear.
• Chronic back pain is defined as pain that continues for 12 weeks or longer, even after an initial injury or underlying cause of acute low back pain has been treated. About 20 percent of people affected by acute low back pain develop chronic low back pain with persistent symptoms at one year. Even if pain persists, it does not always mean there is a medically serious underlying cause or one that can be easily identified and treated. In some cases, treatment successfully relieves chronic low back pain, but in other cases pain continues despite medical and surgical treatment.

Back pain is one of the most common medical problems in the United States. It can range from a dull, constant ache to a sudden, sharp pain. Sometimes it can come on suddenly – from an accident, a fall, or lifting something heavy, or it can develop slowly because of age-related degenerative changes to the spine. In some cases, inflammatory disorders or other medical conditions cause back pain.

Treatment varies depending on the cause and symptoms; however, there are steps you can take to improve your health and lower your chance of developing chronic or long-lasting back pain.

Understanding the Anatomy of the Back

There are many different structures in the anatomy of the back that work together to support your body. Problems with any one of these structures can cause back pain.

• There are four regions of the spine:
  • Cervical spine.
  • Thoracic spine.
  • Lumbar spine.
  • Sacrum and coccyx.

• Parts of the spine and back include:
  • Vertebrae – small bones stacked on top of one another, which protect the spinal cord.
  • Spinal cord – long bundle of nerves that run down the back through a canal in the vertebrae.
  • Intervertebral discs – cushion-like pads between the vertebrae that act like shock absorbers and spacers for the spine.
  • Ligaments – short bands of tough, flexible tissue that hold the vertebrae in place.
  • Tendons – cord of tissue that connects muscle to bone.
  • Muscles – a bundle of dynamic fibers that support your spine and upper body and help you move.

Back pain is one of most common reasons people see a doctor or miss days at work. Back pain can range in intensity from a dull, constant ache to a sudden, sharp or shooting pain. There are two types of back pain:

• Acute (short-term) back pain lasts a few days to a few weeks. It usually resolves on its own within a few days with self-care and there is no long-term loss of function.
• Chronic back pain is pain that continues for 12 weeks or longer, even after an initial injury or underlying cause of back pain has been treated.

Risk factors for low back pain

• Age: The first attack of low back pain typically occurs between the ages of 30 and 50 and may become more common as you age.
• Fitness level: Back pain is more common among people who are not physically fit, as their muscles may not properly support the spine.
• Weight gain: Being overweight, obese, or quickly gaining significant amounts of weight can put stress on your back and cause pain.
• Genetics: Some causes of back pain, such as ankylosing spondylitis (a form of arthritis that affects the spine), have a genetic component.
• Job-related factors: Job that requires heavy lifting, pushing or pulling, or twisting or vibrating the spine can injure your back, as can sitting at a desk all day, especially if you have poor posture or sit in a chair with not enough back support.
• Mental health: Anxiety, mood, and depression can influence how you perceive your back pain and stress can cause muscle tension.
• Smoking: This can restrict blood flow and oxygen to your discs, causing them to degenerate faster.
• Backpack overload in children: A backpack overloaded with schoolbooks and supplies can strain the back and cause muscle fatigue.

Recommendations for keeping your back healthy

• Avoid movements that jolt or strain your back.
• Exercise regularly to keep your muscles strong and flexible. Consult a physician for a list of low-impact, age-appropriate exercises that are specifically targeted to strengthening lower back and abdominal muscles.
• Maintain a healthy weight and eat a nutritious diet that promotes new bone growth.
• Use ergonomically designed furniture and equipment at home and at work.
• Switch sitting positions often and periodically walk around the office or gently stretch your muscles to relieve tension. Put your feet on a low stool or a stack of books when sitting for a long time.
• Wear comfortable, low-heeled shoes.
• Sleeping on your side with your knees drawn up in a fetal position can help open up the joints in the spine and relieve pressure by reducing the curvature of the spine. Always sleep on a firm surface.    
• Don't try to lift objects that are too heavy. Lift from the knees, keep a straight back, and objects close to the body.    
• Quit smoking. Smoking reduces blood flow to the lower spine, which can contribute to spinal disc degeneration. Smoking also increases the risk of osteoporosis and impedes healing. Coughing due to heavy smoking also may cause back pain.

Your backbone, or spine, is made up of 26 bones called vertebrae. In between them are soft disks filled with a jelly-like substance. These disks cushion the vertebrae and keep them in place. As you age, the disks break down or degenerate. As they do, they lose their cushioning ability. This can lead to pain if the back is stressed.

A herniated disk is a disk that ruptures. This allows the jelly-like center of the disk to leak, irritating the nearby nerves. This can cause sciatica or back pain.

Your doctor will diagnose a herniated disk with a physical exam and, sometimes, imaging tests. With treatment, most people recover. Treatments include rest, pain and anti-inflammatory medicines, physical therapy, and sometimes surgery.

Intervertebral Discs and Ligaments of the Vertebral Column

The bodies of adjacent vertebrae are strongly anchored to each other by an intervertebral disc. This structure provides padding between the bones during weight bearing, and because it can change shape, also allows for movement between the vertebrae. Although the total amount of movement available between any two adjacent vertebrae is small, when these movements are summed together along the entire length of the vertebral column, large body movements can be produced. Ligaments that extend along the length of the vertebral column also contribute to its overall support and stability.

Intervertebral Disc. The bodies of adjacent vertebrae are separated and united by an intervertebral disc, which provides padding and allows for movements between adjacent vertebrae. The disc consists of a fibrous outer layer called the anulus fibrosus and a gel-like center called the nucleus pulposus. The intervertebral foramen is the opening formed between adjacent vertebrae for the exit of a spinal nerve.

Amphiarthrosis

An amphiarthrosis is a joint that has limited mobility. An example of this type of joint is the cartilaginous joint that unites the bodies of adjacent vertebrae. Filling the gap between the vertebrae is a thick pad of fibrocartilage called an intervertebral disc. Each intervertebral disc strongly unites the vertebrae but still allows for a limited amount of movement between them. However, the small movements available between adjacent vertebrae can sum together along the length of the vertebral column to provide for large ranges of body movements.

Another example of an amphiarthrosis is the pubic symphysis of the pelvis. This is a cartilaginous joint in which the pubic regions of the right and left hip bones are strongly anchored to each other by fibrocartilage. This joint normally has very little mobility. The strength of the pubic symphysis is important in conferring weight-bearing stability to the pelvis.

Intervertebral Disc

An intervertebral disc is a fibrocartilaginous pad that fills the gap between adjacent vertebral bodies (see image). Each disc is anchored to the bodies of its adjacent vertebrae, thus strongly uniting these. The discs also provide padding between vertebrae during weight bearing. Because of this, intervertebral discs are thin in the cervical region and thickest in the lumbar region, which carries the most body weight. In total, the intervertebral discs account for approximately 25 percent of your body height between the top of the pelvis and the base of the skull. Intervertebral discs are also flexible and can change shape to allow for movements of the vertebral column.

Each intervertebral disc consists of two parts. The anulus fibrosus is the tough, fibrous outer layer of the disc. It forms a circle (anulus = “ring” or “circle”) and is firmly anchored to the outer margins of the adjacent vertebral bodies. Inside is the nucleus pulposus, consisting of a softer, more gel-like material. It has a high water content that serves to resist compression and thus is important for weight bearing. With increasing age, the water content of the nucleus pulposus gradually declines. This causes the disc to become thinner, decreasing total body height somewhat, and reduces the flexibility and range of motion of the disc, making bending more difficult.

The gel-like nature of the nucleus pulposus also allows the intervertebral disc to change shape as one vertebra rocks side to side or forward and back in relation to its neighbors during movements of the vertebral column. Thus, bending forward causes compression of the anterior portion of the disc but expansion of the posterior disc. If the posterior anulus fibrosus is weakened due to injury or increasing age, the pressure exerted on the disc when bending forward and lifting a heavy object can cause the nucleus pulposus to protrude posteriorly through the anulus fibrosus, resulting in a herniated disc (“ruptured” or “slipped” disc) (image). The posterior bulging of the nucleus pulposus can cause compression of a spinal nerve at the point where it exits through the intervertebral foramen, with resulting pain and/or muscle weakness in those body regions supplied by that nerve. The most common sites for disc herniation are the L4/L5 or L5/S1 intervertebral discs, which can cause sciatica, a widespread pain that radiates from the lower back down the thigh and into the leg. Similar injuries of the C5/C6 or C6/C7 intervertebral discs, following forcible hyperflexion of the neck from a collision accident or football injury, can produce pain in the neck, shoulder, and upper limb.

Ligaments of the Vertebral Column

Adjacent vertebrae are united by ligaments that run the length of the vertebral column along both its posterior and anterior aspects (image). These serve to resist excess forward or backward bending movements of the vertebral column, respectively.

The anterior longitudinal ligament runs down the anterior side of the entire vertebral column, uniting the vertebral bodies. It serves to resist excess backward bending of the vertebral column. Protection against this movement is particularly important in the neck, where extreme posterior bending of the head and neck can stretch or tear this ligament, resulting in a painful whiplash injury. Prior to the mandatory installation of seat headrests, whiplash injuries were common for passengers involved in a rear-end automobile collision.

The supraspinous ligament is located on the posterior side of the vertebral column, where it interconnects the spinous processes of the thoracic and lumbar vertebrae. This strong ligament supports the vertebral column during forward bending motions. In the posterior neck, where the cervical spinous processes are short, the supraspinous ligament expands to become the nuchal ligament (nuchae = “nape” or “back of the neck”). The nuchal ligament is attached to the cervical spinous processes and extends upward and posteriorly to attach to the midline base of the skull, out to the external occipital protuberance. It supports the skull and prevents it from falling forward. This ligament is much larger and stronger in four-legged animals such as cows, where the large skull hangs off the front end of the vertebral column. You can easily feel this ligament by first extending your head backward and pressing down on the posterior midline of your neck. Then tilt your head forward and you will fill the nuchal ligament popping out as it tightens to limit anterior bending of the head and neck.

Additional ligaments are located inside the vertebral canal, next to the spinal cord, along the length of the vertebral column. The posterior longitudinal ligament is found anterior to the spinal cord, where it is attached to the posterior sides of the vertebral bodies. Posterior to the spinal cord is the ligamentum flavum (“yellow ligament”). This consists of a series of short, paired ligaments, each of which interconnects the lamina regions of adjacent vertebrae. The ligamentum flavum has large numbers of elastic fibers, which have a yellowish color, allowing it to stretch and then pull back. Both of these ligaments provide important support for the vertebral column when bending forward.

Disorders associated with the curvature of the spine include kyphosis (an excessive posterior curvature of the thoracic region), lordosis (an excessive anterior curvature of the lumbar region), and scoliosis (an abnormal, lateral curvature, accompanied by twisting of the vertebral column).

Disorders of the Vertebral Column

Developmental anomalies, pathological changes, or obesity can enhance the normal vertebral column curves, resulting in the development of abnormal or excessive curvatures (Figure 7.21). Kyphosis, also referred to as humpback or hunchback, is an excessive posterior curvature of the thoracic region. This can develop when osteoporosis causes weakening and erosion of the anterior portions of the upper thoracic vertebrae, resulting in their gradual collapse (Figure 7.22). Lordosis, or swayback, is an excessive anterior curvature of the lumbar region and is most commonly associated with obesity or late pregnancy. The accumulation of body weight in the abdominal region results an anterior shift in the line of gravity that carries the weight of the body. This causes in an anterior tilt of the pelvis and a pronounced enhancement of the lumbar curve.

Scoliosis is an abnormal, lateral curvature, accompanied by twisting of the vertebral column. Compensatory curves may also develop in other areas of the vertebral column to help maintain the head positioned over the feet. Scoliosis is the most common vertebral abnormality among girls. The cause is usually unknown, but it may result from weakness of the back muscles, defects such as differential growth rates in the right and left sides of the vertebral column, or differences in the length of the lower limbs. When present, scoliosis tends to get worse during adolescent growth spurts. Although most individuals do not require treatment, a back brace may be recommended for growing children. In extreme cases, surgery may be required.

Excessive vertebral curves can be identified while an individual stands in the anatomical position. Observe the vertebral profile from the side and then from behind to check for kyphosis or lordosis. Then have the person bend forward. If scoliosis is present, an individual will have difficulty in bending directly forward, and the right and left sides of the back will not be level with each other in the bent position.

Scoliosis causes a sideways curve of your backbone, or spine. These curves are often S- or C-shaped. Scoliosis is most common in late childhood and the early teens, when children grow fast. Girls are more likely to have it than boys. It can run in families. Symptoms include leaning to one side and having uneven shoulders and hips. Sometimes it is easy to notice, but not always.

Children may get screening for scoliosis at school or during a checkup. If it looks like there is a problem, your doctor will use your medical and family history, a physical exam, and imaging tests to make a diagnosis. Treatment depends on your age, how much more you're likely to grow, how much curving there is, and whether the curve is temporary or permanent. People with mild scoliosis might only need checkups to see if the curve is getting worse. Others might need to wear a brace or have surgery.

Spinal stenosis happens when the spaces in the spine narrow and create pressure on the spinal cord and nerve roots. The spinal cord is a bundle of nerves that comes out of the base of the brain and runs down the center of the spine. The nerve roots branch out from the cord. The narrowing usually occurs over time and involves one or more areas of the spine:

• The spinal canal, the hollow space in the center of each vertebrae (bones in the spine that protect the spinal cord); the spinal cord and nerve roots run through the spinal canal.
• The space at the base or roots of nerves branching out from the spinal cord.
• The openings between vertebrae, through which nerves leave the spine and go to other parts of the body.

There are many different structures in the anatomy of the back that work together to support your body. There are four regions of the spine:

• Cervical spine.
• Thoracic spine.
• Lumbar spine.
• Sacrum and coccyx.

Spinal stenosis most commonly develops in the lumbar spine and cervical spine.

The tailbone is the small bone at the bottom of your backbone, or spine. Tailbone disorders include tailbone injuries, pain, infections, cysts and tumors. You rarely break your tailbone. Instead, most injuries cause bruises or pulled ligaments. A backward fall onto a hard surface, such as slipping on ice, is the most common cause of such injuries. Symptoms of various tailbone disorders include pain in the tailbone area, pain upon sitting, pain or numbness in the arms or legs due to pressure on nerves in the tailbone area, and a mass or growth you can see or feel.

Vertebral compression fractures (VCFs) of the spinal column occur secondary to an axial/compressive (and to a lesser extent, flexion) load with resultant biomechanical failure of the bone resulting in a fracture. VCFs by definition compromise the anterior column of the spine, thereby resulting in compromise to the anterior half of the vertebral body (VB) and the anterior longitudinal ligament (ALL). This leads to the characteristic wedge-shaped deformity.

VCFs do not involve the posterior half of the VB and do not involve the posterior osseous components or the posterior ligamentous complex (PLC). The former distinguishes a compression fracture from a burst fracture. The implications of these compression fractures are related to the stability of the resulting structure and potential for deformity progression. Compression fractures are usually considered stable and do not require surgical instrumentation.

Whiplash, also called neck sprain or neck strain, is a soft tissue injury to the neck. It is characterized by a collection of symptoms that occur following damage to the neck, usually because of sudden extension and flexion (bending).

The disorder commonly occurs as the result of an automobile accident and may include injury to intervertebral joints, discs, and ligaments, cervical muscles, and nerve roots. Symptoms such as neck pain may be present directly after the injury or may be delayed for several days. In addition to neck pain, other symptoms may include:

• Neck stiffness
• Injuries to the muscles and ligaments (myofascial injuries)
• Headache
• Dizziness
• Abnormal sensations such as burning or prickling (paresthesias)
• Shoulder or back pain

In addition, some people experience memory loss, impaired concentration, nervousness/irritability, sleep disturbances, fatigue, or depression.

Treatment may include pain medications, nonsteroidal anti-inflammatory drugs, antidepressants, muscle relaxants, and a cervical collar (usually worn for 2 to 3 weeks). Range of motion exercises, physical therapy, and cervical traction also may be prescribed. Supplemental heat application may relieve muscle tension.

Generally, the outlook for individuals with whiplash is good. Most people recover within 3 months after the injury, however, some may have residual neck pain and headaches.

Whiplash is an injury to your muscles, tendons or other soft tissues of your neck. It is caused by a sudden and vigorous movement of the head in one direction, then back again quickly, most commonly during a car accident.

When your neck is forced beyond its usual range of movement, the soft tissues (tendons, muscles and ligaments) may be overstretched or sprained. This causes pain and discomfort in your neck and shoulders and may also cause back pain.