Want More Information? Cedars-Sinai has a range of comprehensive treatment options. See Our Spine Program. Choose a doctor and schedule an appointment. Find a Doctor. Need Help? Available 24 Hours A Day. Schedule a Callback. Adult Primary Care. Pediatric Primary Care. Urgent Care. Looking for a Physician. 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. The neck and lumbar sections of the spine have a lordotic curve, which means that they curve inward. These spinal curves help maintain balance while upright and support the weight of the head and upper body.
However, too much curvature may cause spinal imbalance, causing spinal conditions that may result in pain or loss of mobility. Normal adult spines are positioned over the pelvis, so upright posture doesn't strain muscles. However, changes of spinal position can stress muscles and cause spinal deformity. If the spine is injured and unable to function properly, it can be very painful or even disabling.
Strong muscles and bones, flexible tendons and ligaments, and sensitive nerves contribute to a healthy spine. Yet, any of these structures affected by strain, injury, or disease can cause pain.
When viewed from the side, an adult spine has a natural S-shaped curve. The neck cervical and low back lumbar regions have a slight concave curve, and the thoracic and sacral regions have a gentle convex curve Fig. The curves work like a coiled spring to absorb shock, maintain balance, and allow range of motion throughout the spinal column. The abdominal and back muscles maintain the spine's natural curves.
Good posture involves training your body to stand, walk, sit, and lie so that the least amount of strain is placed on the spine during movement or weight-bearing activities see Posture. Excess body weight, weak muscles, and other forces can pull at the spine's alignment:.
The two main muscle groups that affect the spine are extensors and flexors. The extensor muscles enable us to stand up and lift objects. The extensors are attached to the back of the spine. The flexor muscles are in the front and include the abdominal muscles. These muscles enable us to flex, or bend forward, and are important in lifting and controlling the arch in the lower back. The back muscles stabilize your spine.
Something as common as poor muscle tone or a large belly can pull your entire body out of alignment. Misalignment puts incredible strain on the spine see Exercise for a Healthy Back.
Vertebrae are the 33 individual bones that interlock with each other to form the spinal column. The vertebrae are numbered and divided into regions: cervical, thoracic, lumbar, sacrum, and coccyx Fig. Only the top 24 bones are moveable; the vertebrae of the sacrum and coccyx are fused. The vertebrae in each region have unique features that help them perform their main functions. Cervical neck - the main function of the cervical spine is to support the weight of the head about 10 pounds. The seven cervical vertebrae are numbered C1 to C7.
The neck has the greatest range of motion because of two specialized vertebrae that connect to the skull. The first vertebra C1 is the ring-shaped atlas that connects directly to the skull. The second vertebra C2 is the peg-shaped axis, which has a projection called the odontoid, that the atlas pivots around.
Thoracic mid back - the main function of the thoracic spine is to hold the rib cage and protect the heart and lungs. The twelve thoracic vertebrae are numbered T1 to T The range of motion in the thoracic spine is limited. 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.
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