How many lumbar vertebrae are there

Start New Search. About anatomy of the spine The human spine is a complex anatomic structure that is the scaffolding for the entire body. It provides several important functions, including: Protecting the spinal cord and nerves Structural support for the body, allowing us to stand upright. The spine supports about half the weight of the body.

The spine above the sacrum consists of: Seven bones in the neck—the cervical spine 12 bones in the chest—the thoracic spine Five bones in the lower back—the lumbar spine The spinal column combines strong bones, unique joints, flexible ligaments and tendons, large muscles and highly sensitive nerves.

Some causes of spinal pain include: Irritation of the large nerves as they exit the bony confines of the spine leading to the arms and legs Irritation of the smaller nerves of the spine that involve innervate or supply the discs between the vertebrae, facets and ligaments Strain of the large muscles of the back that hold the spine upright Injuries to the bones, ligaments or joints Damage or disease to the discs that separate the vertebrae Abnormal movement between segments Tumors, infection, trauma, deformity or other spinal disorders The spinal column is made up of many parts, all designed to help the back move flexibly, support body weight and protect the spinal cord and nerves.

All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions. The cervical section of the spine is made up of the top seven vertebrae in the spine, C1 to C7, and is connected to the base of the skull. The top two vertebrae are also know as the atlas and axis, which form the joint for connecting the skull to the spine.

The cervical section is responsible for mobility and normal functioning of the neck, as well as protection of the spinal cord, arteries and nerves that travel from the brain to the body. The thoracic section of the spine is located at chest level, between the cervical and lumbar vertebrae.

The vertebrae in this section are labeled T1 to T12 and serve as attachments for the rib cage. The lumbar section is located between the thoracic vertebrae and the sacrum. The five lumbar vertebrae, labeled L1 to L5, are the main weight-bearing section of the spinal column. The sacrum is the section located at the base of the spine. It does not have discs separating the vertebrae, because its five levels, S1 to S5, are fused together.

The pelvis is connected to the spinal column at the sacrum section. The coccyx is at the very base of the spinal column and is made of four vertebrae that are fused together. The spine is normally a straight line when viewed from the back. If the spine curves to one side or the other, this indicates a condition named scoliosis.

However, the spine does have some normal, gradual curves when viewed from the side. Lumbar low back - the main function of the lumbar spine is to bear the weight of the body. The five lumbar vertebrae are numbered L1 to L5. These vertebrae are much larger in size to absorb the stress of lifting and carrying heavy objects.

Sacrum - the main function of the sacrum is to connect the spine to the hip bones iliac. There are five sacral vertebrae, which are fused together. Together with the iliac bones, they form a ring called the pelvic girdle. Coccyx region - the four fused bones of the coccyx or tailbone provide attachment for ligaments and muscles of the pelvic floor. While vertebrae have unique regional features, every vertebra has three functional parts Fig.

Each vertebra in your spine is separated and cushioned by an intervertebral disc, which keeps the bones from rubbing together. Discs are designed like a radial car tire. The outer ring, called the annulus, has crisscrossing fibrous bands, much like a tire tread.

These bands attach between the bodies of each vertebra. Inside the disc is a gel-filled center called the nucleus, much like a tire tube Fig. Discs function like coiled springs. The crisscrossing fibers of the annulus pull the vertebral bones together against the elastic resistance of the gel-filled nucleus. The nucleus acts like a ball bearing when you move, allowing the vertebral bodies to roll over the incompressible gel. The gel-filled nucleus contains mostly fluid.

This fluid is absorbed during the night as you lie down and is pushed out during the day as you move upright. With age, our discs increasingly lose the ability to reabsorb fluid and become brittle and flatter; this is why we get shorter as we grow older.

Also diseases, such as osteoarthritis and osteoporosis, cause bone spurs osteophytes to grow. Injury and strain can cause discs to bulge or herniate, a condition in which the nucleus is pushed out through the annulus to compress the nerve roots causing back pain. On the back of each vertebra are bony projections that form the vertebral arch. The arch is made of two supporting pedicles and two laminae Fig. The hollow spinal canal contains the spinal cord, fat, ligaments, and blood vessels.

Under each pedicle, a pair of spinal nerves exits the spinal cord and pass through the intervertebral foramen to branch out to your body. Surgeons often remove the lamina of the vertebral arch laminectomy to access the spinal cord and nerves to treat stenosis, tumors, or herniated discs. Seven processes arise from the vertebral arch: the spinous process, two transverse processes, two superior facets, and two inferior facets. The facet joints of the spine allow back motion.

Peer Reviewed. Cramer GD. The Lumbar Region. Elsevier; Wilke H-J, Volkheimer D. Basic Biomechanics of the Lumbar Spine. In: Biomechanics of the Spine. General Characteristics of the Spine. Waxenbaum JA, Futterman B. Anatomy, Back, Lumbar Vertebrae. In: StatPearls [Internet].