From Spine Health
The thoracic spine refers to the upper- and middle-back. It joins the cervical spine and extends down about five inches past the bottom of the shoulder blades, where it connects with the lumbar spine.
The thoracic spine is made up of twelve vertebrae, labeled T1-T12. While the cervical spine is built for flexibility (e.g. turning the head) and the lumbar spine is built for power and flexibility (e.g. lifting heavy objects, touching the toes), the thoracic spine is built for stability. This stability plays an important role in holding the body upright and providing protection for the vital organs in the chest.
There are several features of the thoracic spine that distinguish it from the lumbar and cervical spine:
- Limited flexibility. The rib cage is connected to each level of the thoracic spine. One rib is connected firmly on each side of each thoracic vertebra, with one pair extending from either side of T1, another pair from T2, and so on. The ribs attached to T1-T10 curve around to meet at the front of the body and attach to the chest wall, or sternum. Combined, the thoracic spine and rib cage anchoring each level of the spine from T1-T10 provide both stability and a protected space for the heart, lungs, liver and other vital organs.The ribs connected to T11 and T12 at the bottom of the thoracic spine do not attach the sternum in front, but do provide protection for the kidneys in the back of the body. Because these levels have slightly less stability, they are slightly more prone to problems that can cause pain.
- Thinner intervertebral discs. Between each of the spine’s 24 unfused vertebrae are intervertebral discs, spongy pads that act as shock absorbers. In the thoracic spine, the intervertebral discs are thinner than at the cervical or lower spine. This adds to the thoracic spine’s relative inflexibility. Despite the thinner discs, it is still less common to have disc problems in the thoracic spine due to the limited flexibility.
- Narrower spinal canal. The cervical and thoracic spine forms a protected, hollow core for the spinal cord to pass through, called the spinal canal. This canal is most narrow in the thoracic spine, and therefore the spinal cord is at a risk for damage if a thoracic vertebra is injured.
Upper Back Pain and the Thoracic Spine
The thoracic spine is an intricate construct of bones, connective tissues, nerves, muscles, spinal segments, and joints. While the thoracic spine has a solid construction and is relatively stable, it can also be a source of pain.
- Muscular problems. Upper back pain is most commonly caused by muscle irritation or tension, also called myofascial pain. The cause may be poor posture or any type of irritation of the large back and shoulder muscles.
- Joint Dysfunction. Pain caused by joint dysfunction, where the ribs attach to the spine at each level of the thoracic spine, can cause pain.
- Herniated or degenerative discs. While less common in the thoracic spine, degenerative disc disease or a thoracic herniated disc can be a source of pain.
- Arthritis. Swelling due to arthritis in the spine can cause tenderness, pressure to the nerve, and limited range of motion. Often due to wear and tear of the aging process, the cartilage in the facet joints can become thin or disappear or can produce an overgrowth of bone spurs and an enlargement of the joints. Facet joint disorders of the thoracic spine can result from osteoarthritis.
- Vertebral fractures. Compression fractures due to osteoporosis are a main cause of thoracic spine pain in the elderly. While compression fractures can occur anywhere in the spine, they typically occur in the lower vertebrae of the thoracic spine (T9-T12).
- Kyphosis (hunchback). In addition to vertebral fractures, kyphosis can be caused by many factors, such as poor posture or a deformity, such as ankylosing spondylitis or Scheuermann’s kyphosis. While kyphosis is primarily a deformity, it can also be a source of pain.
- Scoliosis. Scoliosis is a condition in which the spine abnormally curves sideways and can sometimes produce upper back pain.
Occasionally, pain felt in the thoracic spine can be a symptom of a more serious underlying disease or problem. Both musculoskeletal diseases and non-orthopedic conditions (such as a cancerous tumor exerting pressure on the spine) can cause upper back pain, as well as certain diseases of the heart, lungs, abdominal organs, or kidneys.