What is the lumbar spine?
The lower part of the back, also called the lumbar spine, is made up of five bones called vertebrae which are given the labels L1 through L5. The lumbar spine is located between the chest, or thoracic area, and the lowest portion of the spinal column, known as the sacrum. Lumbar is a word that was taken from a Latin word that means “lion.”
The lumbar spine usually curves just slightly inward. This curve is called lordosis. The curve of the lumbar spine, as well as the other spinal curves helps provide balance and also protection from vibrations and shocks as the body moves. The lumbar spine area contains muscles that are quite large. These provide support for the back and they allow the body’s trunk to move. A common reason for low back pain is muscle spasms that occur when these large muscles are strained.
Special joints called “facet” connect the five bones (vertebrae) of the lumbar spine. These allow the lumbar spine to twist, extend backward and bend forward. The lowest segments of the lumbar spine have the most mobility. These segments are also responsible for carrying the most weight, so they are at increased risk of being injured.
Reasons for Lumbar Spine Problems
Intervertebral discs lie between the vertebrae of the lumbar spine. These provide support and cushioning for the bones. The
intervertebral discs found in the lower or lumbar spine are more likely to degenerate and then herniate or bulge than other discs of the spine. This is because they move more, so wear out more quickly. A bulging or herniated disc, or one that is degenerated, can cause inflammation and pressure on the nerves. This can be a reason for low back pain, and it can also be a reason for the pain that travels down into the buttocks and radiates to the back of the thighs and down the legs into the feet - sciatica. Pain related to compressed nerves is sometimes called radiculopathy.
The spinal cord starts at the base of the skull and ends at the point where the lumbar spine and the thoracic spine meet. The cauda equina is found here, which is a group or bundle of nerve roots branching out from the spinal cord.
The cauda equina was named for its similarity in appearance to the tail of a horse. There are many nerves in this bundle, extending from the lumbar spine to provide nerve function to the feet, legs, and buttocks. Since the spinal cord itself does not pass through the lumbar spine, spinal cord damage rarely result from injury or insult to the lower back. Cauda equina syndrome is a very serious condition, however.
Lumbar Spine Problems
Here are some of the most common lumbar spine diseases:
- Degenerative Disc Disease - Degenerative disc disease or degenerative disc disorder, sometimes called DDD, occurs when one or more of the discs that lie between the vertebrae of the spine begin to dehydrate, shrink or compress. Discs begin to degenerate as a normal part of aging and for many people, this doesn't cause problems. But in other people, degenerative disc disease that is not treated causes severe and on-going neck or back pain.
- Spinal Disc Herniation - A herniated disc occurs when the nucleus pulposus, which is the gel-like inner substance of an intervertebral disc, breaks through the annulus fibrosus, which is the tough, outer rim of the tire-like structure. Pain is the most common symptom. However, nerve compression and inflammation can cause other symptoms including numbness, tingling and/or weakness in the extremities can also occur with a herniated disc.
- Spinal Stenosis - Spinal stenosis is a condition that occurs when the spaces in your backbone (spine) become narrow. When this happens, your spinal cord and its nerves can become compressed or pinched. More than half the time, spinal stenosis occurs in the lumbar spine, which is the lower portion of the back, and the narrowing of the spine that goes along with this condition causes pain that travels down the back of the leg.
- Sciatica - Compression and irritation of your sciatic nerve or its nerve roots can cause sciatica, which is the medical term used to describe a set of symptoms that commonly occur together. Your sciatic nerves have their origin in your lower spine area and travel down the back of your thighs and legs. They are responsible for muscle movement in the legs and are also responsible for the feelings of pain and touch in the legs.
- Scoliosis - When a person has scoliosis, this straight line is curved. Scoliosis most often occurs during a person’s growth spurt just right before hitting puberty and can be mild and stay stable over time while others get progressively worse and show a significant degree of curvature.
- Radiculopathy - Radiculopathy is used to describe a variety of sensations (mostly pain) that originates from the middle portion of a person’s spine. The most common type of radiculopathy is Lumbar Radiculopathy, which refers to a variety of sensations (same as thoracic radiculopathy) that comes from the lower back part of the spine.
- Spondylolisthesis - Spondylolisthesis is defined as the displacement or slippage of one your vertebra compared to another or all others. It is a condition that occurs when your vertebra (the bone in your back) slides forward and over the bone below it.
- Myelopathy - Myelopathy is a medical term that is used to describe any neurological disorder of the spinal cord. It is typically caused by compression of the spinal cord due to bone spurs, also known as Osteophytes, or by herniated or “ruptured” discs in the spine.
- Lordosis - Lordosis of the spine pertains to an individual's characteristic lordotic bend, which is ordinary. However, in the event that an individual's bend curves too far inside, it's called lordosis, or swayback. Lordosis of the spine can influence the lower back and neck.
- Kyphosis - Kyphosis is the medical term for "hunchback." It happens when the upper portion of the spine (the thoracic) region is abnormally curved forward. Some forward curvature in this region is normal, but if the curve is greater than 50 degrees the condition is considered to be "kyphotic" which is abnormal.