Introduction
Back pain is one of the most common reasons people visit their doctor. According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, 8 out of 10 people have some type of backache.
Back pain can be acute or chronic. Acute pain develops suddenly and goes away within 6 weeks. Chronic pain can come on fast or slow, but it lasts longer than 3 months. Back pain can occur in any area of the back, but it is more common in the lower part, which supports most of the body’s weight.

The Spine
The back is highly complex, and pain may result from damage or injury to any of various bones, nerves, muscles, ligaments, and other structures. Still, despite sophisticated techniques that provide detailed anatomical images of the spine and other tissues, the cause of most cases of back pain remain elusive.
Vertebrae. The spine is a column of small bones, or vertebrae, that support the entire upper body. The column is grouped into three sections.
- The cervical (C) vertebrae are the seven spinal bones that support the neck.
- The thoracic (T) vertebrae are the twelve spinal bones that connect to the rib cage.
- The lumbar (L) vertebrae are the five lowest and largest bones of the spinal column. Most of the body's weight and stress falls on the lumbar vertebrae.
![]() | Click the icon to see an image of the spine. |
Below the lumbar region is the sacrum, a shield-shaped bony structure that connects with the pelvis at the sacroiliac joints.
At the end of the sacrum are two to four tiny, partially fused vertebrae known as the coccyx or "tail bone."
![]() | Click the icon to see an image of the sacrum. |
Each vertebra is designated by using a letter and number, which allows the doctor to determine where it is in the spine.








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