Workplace Safety Guides

   Construction of the Back


The back is a mechanical wonder and very flexible. It consists of a bony spinal column, muscles, and ligaments. The main purpose of the back is to support the upper body and protect the spinal cord.

The spinal column has four natural curves that act like arches of a bridge. These arches allow us to load the spine 16 times more than if it were straight. The key to preventing back problems is to maintain these natural curves while standing, lifting, sitting, or just doing everyday tasks.

The spine is made up of 24 moving vertebrae. There are seven in the neck called cervical. Problems in this area can cause pain in the neck, shoulders, and arms.

The 12 in the back, called thoracic, run through the neck into the rib cage. Many problems in this area imitate heart trouble, pleurisy, or causes numbness.

The five vertebrae at the bottom of the spine are called lumbar. The lumbar area supports most of the upper body weight. It is most vulnerable to injury and is where most pain occurs. Problems in this area can cause pain in the lumbar area and in the legs.

The vertebrae are stacked one on top of the other and are attached by a cartilage like cushion called a disc. These discs have the ability to bulge and act like coil springs or shock absorbers. They also prevent one vertebra from sliding on to another.

The vertebra, in combination with the discs, allows the body to be stable and very flexible. The spinal cord is located in a protective passage of each vertebra and behind the discs. It is a bundle of individual nerves, or branches, that send out nerves into other parts of the body to pick up sensations and control motion.

The vertebrae are held together by ligaments, cartilage, and muscles. Other muscles of the entire trunk, legs, and upper arms also help control and reinforce the spine.

The longitudinal ligaments run down both the front and rear of the spine and are attached to each vertebra. These ligaments give support to the spine and protect it from over-flexing.

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