Back pain is a very common condition. In the vast majority of cases, the pain is self limiting and is improved with non-operative care (medications and physical therapy) within 4-6 weeks.
Most cases of low back pain occur because of a non-serious cause, such as muscle or ligament strain, or strain of the fascia (the sock that covers the muscles).
Causes of pain include those related to the muscles, skeleton, and connective tissues, even including injuries to the discs and joints of the back. However, on occasion, back pain can be caused by other conditions related to the internal organs like a kidney stone or diverticulitis. The diagnosis can usually be made by a careful history and physical exam.
On a normal MRI, pictured here, the center of the disc, called the nucleus, which is like the center of a jelly donut, appears white. The rim of the disc, the annulus, like the dough of the donut, is not bulging backwards toward the nerves.
On this MRI, however, which shows an abnormal disc at L4-5, the jelly and dough are bulging backwards toward the nerves. This disc also is not working as an effective cushion between the bones.
A poorly functioning disc can lead to pain in the back, the buttock, and thigh, depending on which disc is involved, due to referred pain patterns.
When the discs go bad, when they dry out and degenerate, as pictured here, the facets (pictured below to the right) can be affected also.
While the discs help support the spine in front of the spinal nerves, the facet joints are the moving parts in the back part of the spine. These facet joints can also be a cause of pain. The joints which are covered with articular cartilage (like the kind on the end of a chicken bone) can wear out and get arthritis and cause pain.
For information on worn out facets, click here.