With seven cervical vertebrae above it and five lumbar, five sacral, and four coccygeal vertebrae below, the 12 vertebrae of the thoracic region (T1 – T 12) together make up the longest portion of the spine. But the word thoracic refers to the thorax, or chest. Why is part of the spine named for the chest? The answer lies in its anatomy: Each of the 12 thoracic vertebrae is attached to a pair of ribs, forming the thorax, or rib cage. The space within this cage is known as the thoracic cavity or chest cavity. The word thorax itself comes from the Greek word thōrēssō, meaning "to arm"—think of a medieval knight donning his lance and armored breastplate. Certain disorders of the thoracic spine affect the vital organs within the thoracic cavity. For example, a profound curvature the thoracic spine can leave too little space for lung expansion, compromising cardiorespiratory function.
What is a thoracic spine disorder?
A disorder of the thoracic spine is any disease or condition that produces pain or alters the function of this region. The thoracic spine has several important roles:
- It anchors the rib cage, which shields your lungs, esophagus, great vessels (such as the thoracic portion of the aorta, the body’s main artery), and heart. The heart, in fact, lies at the level of the fifth through eighth thoracic vertebrae.
- It serves as a point of attachment for the trunk muscles and ligaments.
- It protects the spinal cord and the 12 pairs of spinal nerves at the thoracic level. These nerves are part of the sympathetic division of the autonomic nervous system. You might remember from your high school biology class that this division controls your fight-or-flight response in stressful situations.
- It works with the rest of your spine to support and distribute your body weight and allow a broad range of motion as you go about your daily life.
The list of disorders that can affect the thoracic spine includes inherited and congenital conditions, degenerative and infectious processes, nutritional and metabolic disorders, neoplasms (cancer), and more. Let’s cover a few of the more common structural disorders of the thoracic spine that are associated with pain and other troublesome symptoms.
Thoracic disc herniation
Thoracic disc herniation is less common than disc herniation in the cervical spine (neck) and lumbar spine (lower back), and it usually produces no symptoms. As with disc herniation in any other portion of the spine, thoracic disc herniation is of concern only when it provokes pain or causes some dysfunction, such as difficulty walking. See Herniated Disc for a full explanation of the causes, symptoms, and recommended treatment of disc herniation.
Curvature of the thoracic spine
Aging and certain disease processes can change the natural convex curvature of the thoracic spine. If the curvature is severe enough, it can restrict lung expansion and compromise breathing.
The thoracic spine can develop an exaggerated curvature called kyphosis, giving the back a hunched appearance. Kyphosis is usually caused by aging and associated loss of bone mass; however, kyphosis can also develop as a result of other diseases, such as Marfan syndrome and Scheuermann’s disease.
Normal thoracic vertebrae have a uniform thickness from side to side. People with Scheuermann’s disease have thoracic vertebrae of uneven thickness. Stacked on top of one another, these wedge-shaped vertebrae form an abnormal curvature. Picture a pile of stapled handouts—if the stack is tall enough, it’ll begin to curve inward at the stapled corner.
When the thoracic and lumbar spine curve 10 or more from side to side, the condition is called thoracolumbar scoliosis. Click here for a full review of this topic.
As we age, we lose bone mass, a condition called osteoporosis. Even the vertebrae of the spine can become osteoporotic, making them vulnerable to compression fractures that gradually reduce a person’s overall height with age. Often such fractures produce no symptoms, but in some people they can cause sharp, intense pain. About 20% of people with a fractured thoracic vertebra will endure another vertebral fracture within a year.
How common are thoracic spine disorders?
Patients with thoracic issues represent less than 1% of all patients with disc herniation. Most cases of disc herniation involve the cervical or lumbar portion of the spine.
Symptomatic thoracic disc herniation is more common among men than women, and most people are diagnosed in their 30s or 40s. The incidence of this condition among the general population is literally one in a million.
Disorders affecting the curvature of the thoracic spine, on the other hand, are very common. A recent British study of more than 600 elderly adults found that 20% to 40% of the study population had kyphosis.
Among women over age 50, 40% can expect to sustain an osteoporosis-related compression fracture. Such fractures are three times more common among men compared with women.
What causes thoracic spine disorders?
Perhaps surprisingly, given its length and its important functions, the thoracic region is the portion of the spine least associated with back pain. That’s because the thoracic vertebrae are attached to the rib cage with strong ligaments, stabilizing the mid-back and reducing its range of motion. In fact, there’s virtually no flexion in the thoracic spine when you bend forward. Less twisting and turning means less wear and tear on the intervertebral discs. And compared with elsewhere in the spine, more force is necessary to fracture a thoracic vertebra or cause traumatic disc herniation (herniation preceded by an accident or injury).
Nevertheless, several factors make the thoracic spine vulnerable:
- The thoracic region, with it 12 vertebrae, is the longest portion of the spine. Its sheer length makes it a frequent site of injury, then, just as a long, lightly trafficked road might be the site of more accidents than a heavily trafficked but much shorter stretch (in other words, the five cervical or five lumbar vertebrae).
- The spinal canal, which is roomy in other portions of the spine to allow a broad range of motion, is narrower in the thoracic spine. That leaves a smaller margin of error. When an accident occurs or a disease process affects the thoracic spine, the cord is easily damaged.
- Both the vertebrae and the discs in the thoracic region are thinner than in the cervical or lumbar regions.
What are the symptoms of a thoracic spine disorder?
Because the thoracic spine anchors the rib cage, the spinal nerves at levels T1 through T12 supply sensation not just to the middle portion of the back, but also to areas of the front of the body, such as the nipples and the umbilicus (belly button). Thus the pain associated with thoracic disc herniation and other structural disorders is usually not well localized, meaning that it’s hard for the patient to point to one specific place where it hurts. Instead, this kind of pain tends to be more generalized, radiating to areas of the body as far afield as the groin and the forearm.
Herniation of a disc in the thoracic spine can cause myelopathy (pain caused by spinal cord compression) or radiculopathy (pain caused by compression of a spinal nerve). Pain produced by herniation of the first thoracic disc can be mistaken for pain associated with herniation of the last disc in the cervical spine. Likewise, symptoms of herniation at the lower levels of the thoracic spine may be interpreted as evidence of lumbar herniation.
Pain associated with a disc herniation, compression fracture, or kyphosis is often aggravated by coughing, sneezing, lifting, or doing anything else that increases pressure within the thoracic cavity. Herniation of a disc at the thoracic level may cause more severe pain than a herniation at the cervical or lumbar level might because the spinal canal is narrower in the thoracic region. On the other hand, this part of the spine is relatively stationary, which might make it easier for a patient to remain in a comfortable position most of the time.
In fact, constant pain that’s not eased by a change in position indicates that the problem might not simply be structural. Talk to your doctor right away. You should also seek medical attention immediately if your pain coincides with recent or current use of corticosteroid medications (such as Prednisone), which can reduce bone mass, or if it began after a recent trauma (such as a fall or car accident). You should Seek emergency medical treatment for any sudden loss of bowel or bladder function, which may indicate that you have a dangerous condition called cauda equina syndrome.
How are thoracic spine disorders diagnosed?
Your doctor will ask about your general medical history, including your medications and any past surgeries. He or she will ask you to characterize your pain—for instance, is it sharp, stabbing, or aching? Does it feel like an electric shock?
The physician will want to know when the pain began, what (if anything) brought it on, whether it’s constant or intermittent, and which activities (such as lifting or bending) make it worse or better. The doctor will perform a thorough physical examination to assess your strength, sensation (for example, with a pinprick test), reflexes (such as checking for Hoffmann’s sign and the Babinski reflex), and gait (walking ability). Patients with disorders of the thoracic spine often have what’s called a “wide-based gait”—slow, lumbering, awkward movements.
Your doctor may send you for x-rays to exclude other conditions associated with back pain, such as fractures and tumors. You might be asked to remain standing as these x-rays are taken, so that doctors can see how your spine looks in a weight-bearing position. The resulting x-ray pictures are called upright radiographs.
If your pain persists after at least 6 weeks of conservative treatment (see “How are thoracic spine disorders treated?”), your physician will probably also order a magnetic resonance imaging (MRI) scan of the spine. An MRI can confirm the diagnosis of disc herniation, reveal the precise location of the herniation, and show any associated inflammation, swelling, or changes in the vertebral endplates or bone marrow.
A sophisticated magnetic resonance scan called diffusion tensor imaging (DTI) can reveal nerve root compression at a microscopic level, supplying granular information that’s helpful in surgical planning.
How are thoracic spine disorders treated?
Your physician will probably allow 6 to 12 weeks to elapse before pursuing any treatment or diagnostic testing, since most back pain resolves on its own. Treatment of thoracic pain syndromes begins with physical therapy and nonopioid medications, progressing to prescription pain medication and surgical intervention as needed.
A physical therapist can perform an in-depth assessment and design a treatment plan for you. It might include activity modification, range-of-motion exercises, aerobic fitness activities, application of heat or ice, ultrasound, or electrical muscle stimulation using a transcutaneous electrical nerve stimulation (TENS) unit. The therapist can show you range-of-motion, strengthening, and conditioning exercises that may improve spinal function and ease pain.
For pain relief, your doctor can prescribe a combination of medications. These include narcotic (opioid) analgesics, nonsteroidal anti-inflammatory drugs (NSAIDs), anticonvulsants, and antidepressants. Anticonvulsants aren’t prescribed for convulsions, though—medications such as gabapentin (Neurontin) block certain nerve pain signals in patients with disc herniation. Likewise, antidepressants can relieve pain and are often prescribed to patients who have no symptoms of depression.
Using x-ray guidance, your doctor can administer an intercostal nerve block (inter– means “between” and costal refers to the ribs). This intervention can disrupt transmission of pain signals for as long as 3 months.
For some conditions, such as certain forms of scoliosis and any progressive myelopathy (compression of the spinal cord), surgery is necessary in order to maintain normal functioning. For pain patients, surgery becomes an option if your pain lasts 6 months or longer despite conservative treatment, or if you have signs of chronic neurologic dysfunction (such as difficulty walking). All surgery involves risk, so discuss the options with your doctor and weigh them carefully:
- Traditional open surgery. Traditional open surgery is an invasive procedure that carries special risks. The surgeon may have to cut through layers of muscle and other tissue to reach the operative site. Wound healing may be delayed. You’ll also have a less satisfying cosmetic result. Of course, traditional surgery also offers the promise of healing and pain relief. Many people with chronic pain are willing to assume some risk and endure a period of recovery in order to achieve the expected benefit of the procedure.
- Minimally invasive surgery (MIS). Minimally invasive surgery, open surgery or, more specifically, minimally invasive spine surgery (MISS) reduces operative time, blood loss, risk of infection, and recovery time, and yields a better cosmetic result. Nevertheless, there’s still enough tissue damage to require a short hospital stay and several weeks of recovery time.
- Keyhole surgery. Keyhole surgery requires an incision no wider than an aspirin tablet. Surgeons use specially adapted tools to operate through this portal. Fluoroscopy—real-time x-ray guidance—eliminates the need for direct visualization of the surgical field. A specialized new keyhole procedure called minimally invasive direct thoracic interbody fusion (MIS-DTIF) may be appropriate if you have a thoracic disc herniation at the level T6-7 or below. The procedure involves removing the herniated disc, replacing it with a graft and/or a small cage-like device that substitutes for the disc, and fusing the affected vertebrae with the aid of sturdy orthopedic hardware. Ask your doctor if you’re a candidate for this procedure. A preliminary study showed that it reduced patients’ pain from an average of 8.8 to an average of 3.5 on a 10-point scale.
Certain factors can affect the likelihood of a good surgical outcome. For more information, see What’s the Difference Between Traditional (Invasive), Minimally Invasive, and Keyhole Surgery?
Keep in mind that if you have thoracic spine surgery, you’ll face a somewhat longer recovery than that of a patient who has surgery on the cervical or lumbar spine. That’s because, as we’ve mentioned, the spinal canal is narrower in the thoracic region. In addition, the spinal cord is not as richly supplied with oxygen at the thoracic level as it is above and below. Thus any swelling brought on by an overzealous return to work and other normal activities could have serious consequences.
Take it slow and follow your doctor’s orders, though, and it’s likely you’ll have a good outcome and perhaps feel better than you have in months or years.