Skeletal bones form the framework of our bodies, and in the previous section we talked about the joints and discs that link the bones. But something has to secure all these pieces in place. These are mainly ligaments, tendons, and muscles, all types of connective tissue. Each provides both stability and mobility to a greater or lesser degree.
Connective tissue is a broad term referring to various types of tissue that connect and support structures literally everywhere in the body. Collagen, tendons, and even muscles are types of connective tissue. Fascia, a type connective tissue that lies just under the surface of the skin, can tighten and cause pain in various parts of the body, including the back. Some diseases such as rheumatoid arthritis are considered connective tissue disorders.
Ligaments are like the chief of security, whose job it is to prevent suspicious activity while allowing normal activity. Likewise, spinal ligaments allow some forward, back, and side motion, but they put on the brakes to reduce excessive motion that could cause damage.
The posterior longitudinal ligament runs along the back of the vertebrae, and the supraspinous ligament attaches to the tips of the spinous processes. In combination, these two limit how far forward we can bend. Of course, it's possible to overstretch ligaments and—you guessed it—that can be a cause of back pain.
Jason Highsmith, MD is a practicing neurosurgeon in Charleston, NC and the author of The Complete Idiot's Guide to Back Pain. Click here for more information about the book.