Back school is in session.

Sit up straight. Stand tall. You’ve heard it before. Yet until back pain strikes, we often take good posture for granted. Proper posture is more than simply sitting up or standing as straight and tall as you can. It’s about finding a balanced, comfortable, and efficient spine posture. That’s what this lesson on Postural Education is all about.

In Lesson One, you discovered the importance of gradually increasing your activity. The information you'll learn and master in this lesson includes a detailed explanation of spine anatomy. Putting your spine anatomy to work will ensure that you know how to position your back for maximum comfort and protection. It'll also help as you position yourself for moving, lifting, and exercising.

Anatomy 101

The human spine is made up of 24 spinal bones, called vertebrae. Vertebrae are stacked on top of one another to create the spinal column.

As you’ll recall from Lesson One, the spinal column has three natural curves when viewed from the side. These curves help balance and cushion the spine. The neck and low back curve inward. An inward spinal curve is called lordosis. The midback curves outward, called kyphosis.

The low back (lumbar spine) is made up of the lower five vertebrae. These vertebrae are commonly referred to as L1 to L5. The lowest vertebra of the lumbar spine, L5, connects to the top of the sacrum, the triangular bone at the base of the spine that fits between the two pelvic bones.

Each vertebra is formed by a round block of bone, called a vertebral body. A bony ring attaches to the back of each vertebral body. The ring is made of the lamina and pedicle bones. When the vertebrae are stacked on top of each other, the rings form a hollow tube of bone, called the spinal canal. The spinal canal surrounds the spinal cord as it passes through the spine. Just as the skull protects the brain, the bones of the spinal column protect the spinal cord.

As the spinal cord travels from the brain down through the spine, it sends out nerves on the sides of each vertebra called spinal nerves. These individual nerves join together with other spinal nerves to form the main nerves that travel throughout the body and form the body's electrical system. It is sometimes easier to understand what happens in the spine by looking at a spinal segment.

A spinal segment includes two vertebrae separated by an intervertebral disc, the nerves that leave the spinal cord at that level, and the small joints that link each level of the spinal column.

The intervertebral disc sits between two vertebrae. The disc is made up of two parts. The center, called the nucleus, is spongy. It provides most of the disc's ability to absorb shock. The nucleus is held in place by the annulus, a series of strong ligament rings surrounding it. Ligaments are strong connective tissues that attach bones to other bones.

Between the vertebrae of each spinal segment are facet joints. The facet joints are located on the back of the spinal column. There are two facet joints between each pair of vertebrae, one on each side of the spine. The surfaces of the facet joints are covered by articular cartilage. Articular cartilage is a smooth, rubbery material that covers the ends of most joints. It allows the bone ends to move against each other smoothly, without friction.

The lumbar spine is supported by ligaments and muscles. The ligaments are arranged in various layers and run in multiple directions. The back muscles are also arranged in layers. Those closest to the surface are covered by a thick tissue called fascia. The middle layer, called the erector spinae, has long and thin muscles that run up and down over the ribs and low back. They come together in the lumbar spine to form a thick tendon that binds the bones of the low back, pelvis, and sacrum. The deepest layer of muscles that attach along the back surface of the vertebrae connect the low back, pelvis, and sacrum. These deep muscles coordinate their actions with the muscles of the abdomen to help hold the spine steady during activity.

Anatomy Wise

Your knowledge of anatomy gives you a new advantage. Now you'll know how—and why—to position your spine for improved comfort. Don’t get the idea that good posture is determined by whether you can balance a chalkboard eraser on your head. Rather, you’re assignment is to begin putting anatomy into practice in order to protect your spine from abnormal and excessive stress and strain.

Here's why. Bones, joints, and muscles work best when they are centered. If they are bent or stretched too far in one direction, they are not centered. They are out of balance. Strain from this imbalance can make your back pain worse. Centering the spine in its neutral alignment (slight lordosis) is generally a safer position and one that helps take pressure off sore areas of your back.

When the parts of the spine are out of balance, they don't work as well. For example, a muscle is weakest when it is stretched out or when it is already contracted (shortened) all the way. The same muscle is strongest between the two extremes of being stretched or shortened all the way. The muscles of the low back and abdomen work best when the spine is kept in its neutral position.

Using imbalanced spine postures upsets lifelong spine health. The strain from these imbalances may not be felt at first. But with time, they can take a toll on the parts of the spine and one day become a back problem.

To illustrate, look at your hands. Notice that the fingers are in a balanced position, curving gradually from the back of the hand to the finger tips. Now bend and hold one of your fingers gently backward. At first, the stretch you feel in your bent finger may actually feel good. However, because your finger is in an awkward alignment, one that is not "centered," you'll eventually begin to feel discomfort. Keep it there for too long, and the discomfort will give way to actual pain. The pain eases when you let go and allow the finger to resume its balanced position again.

The same is true for your back. Imbalanced spine postures may not feel like they're a problem. You might actually feel comfortable at first, such as when you initially sit or work with slouched posture. But with time, the small strains on the spine begin to add up. Eventually damage and symptoms may occur.

The discs are affected by the position of your spine. When you bend forward, the front of the discs are squeezed as the front edge of the vertebrae above and below pinch together. This pressure pushes the nucleus in the middle of the disc backward against the annulus (the ligament ring around the nucleus). If the annulus is weak, the nucleus can squeeze through, causing a disc bulge or disc herniation. The opposite pressure occurs with back bending; the nucleus pushes forward. Positioning the spine in neutral keeps the nucleus centered inside the disc.

A+ Posture

Low back posture depends on the position of your pelvis. You can change the alignment of your low back by rolling your pelvis back and forth. For example, tilting your pelvis forward pushes your buttocks out (extension). Tilting your pelvis backward pulls your buttocks in (flexion). When the lower spine is centered between the two extremes of extension and flexion, it is in neutral. You get extra credit when apply the neutral position as you rest, move, and exercise.

Stretches

Stretching is the basis for muscle balance in the spine. Flexibility exercises address areas of muscle tightness that may be causing a muscle imbalance. Gentle stretching is a way to relax muscles and ease pain. Flexibility does not happen right away. It takes time and effort to attain muscle balance. As your flexibility improves, you may find it easier to do other exercises and to keep better body alignment when doing your activities throughout the day.

Aerobic Conditioning

Current guidelines for low back pain include recommendations to begin aerobic conditioning soon after the onset of low back pain, usually within two weeks. Aerobic exercise may be recommended to help you avoid potential debilitating effects of back pain, such as spine inflexibility, muscle weakness, and weight gain.

There are many ways to get a good aerobic workout. Aerobic exercises include walking on a treadmill, riding a stationary bike, using an elliptical trainer, or swimming. These activities can relieve the stress that often goes along with low back pain, and they help your body to release endorphins into your blood stream. Endorphins are the body's own natural painkillers.

At first, the goal is to gradually increase the amount of time you're doing aerobic exercise, not how hard you're working out. When you've comfortably worked up to 20 or 30 minutes during an aerobic workout, you're encouraged to increase the intensity of the exercise.