Your Back's Anatomy

Inversion therapy

Practiced as early as 400 B.C.E., inversion therapy is hardly a new fad. Rather, it is an ancient system whose credibility is getting increasing support from myriad sources. Today, physical therapists, chiropractors, and medical doctors all utilize gravity assisted traction, and medical studies attest to its viability.

Your back

The exact condition of your back figures massively into your health. A better back means a healthier body. Each vertebra is secured in its correct position by three different kinds of soft tissue: discs, ligaments, and muscles. Nearly all back problems relate to the dysfunction of one or more of these tissues.

To diagnose the sources of your particular back problem and/or to prevent back pain, it helps to understand your spine's anatomy.

Vertebrae

The strength and resiliency of your back vitally depend upon the natural curves of your spine. Your spinal column has 24 vertebrae. The lumbar vertebrae have an approximate diameter of 2 inches, a thickness that reflects their weight-bearing role. The cervical vertebrae only have to support the head, and thus are smaller. One finds facet joints located in pairs on the back of the spine, where one vertebra slightly overlaps the next. These facet joints guide and restrict movement of the spine at these critical junctures. Towards the rear of each vertebra is a slight hole, and when the vertebrae stack up in the spinal column, these holes create a continuous channel which holds the spinal cord.

Spinal cord

The spinal cord critically links the brain to all body functions below the neck. This includes all internal organs and all feelings and sensations. Important spinal nerves emerge from the spinal cord via gaps between the vertebrae and facet joints. One of the most frequent causes of back pain is a damaged facet joint, which often results in a pinched nerve. Therefore, keeping your vertebrae in good shape has a significant effect on your health.

Discs

Your discs mainly function as shock absorbers and as separators between each vertebra. Tough cartilage forms the outer layers of your discs. The inner core of your disc is a softer, jelly-like nucleus.

In total, your discs account for one-quarter of your vertebral column's length, about 4.5 to 6 inches (12 to 15 cm) for most people.

The disc finds nourishment by way of the fluid-attracting and fluid-absorbing nucleus. Without a blood supply of its own, the disc depends upon absorption, finding nutrients from adjacent tissues. During non-weight bearing activities (such as sleeping) the discs expand as they soak up fluid, lengthening the spine by as much as one inch overnight. In weight-bearing activities (sitting, standing, exercising), the pressure forces the fluids back into the adjacent soft tissue.

Muscles

Your vertebrae critically rely upon many different muscles. Muscles have three basic functions for your spine: support, movement, and posture control. Tight, weak, or injured muscles create or worsen back pain. At least two sets of muscles control the joints: flexors, which bend the joint, and extensors, which straighten it. Additionally, most joints have rotator muscles, allowing your bones to twist and rotate. Good posture requires a proper balance between the flexors, extensors, and rotators.

Your paraspinal muscles (which run parallel to your spine) rotate your spine, bending it backwards and sideways, and influence posture by creating and maintaining the curves of your spine.

Your erector spine muscles, involved in movement, run the length of your spine. These muscles help you to bend over safely by resisting the force of gravity, as well as assisting you in straightening up by contracting themselves, exerting great compressive force on your spine.

Your abdominal muscles maintain critical pressure inside the abdomen, playing an important role in helping to support the spine. This pressure provides essential counter-support to the spine.

Your psoas muscles (hip flexors) are a large group of muscles within the abdomen. These muscles help to flex your hips when walking or climbing stairs, and they also sustain good posture for sitting and standing.

Ligaments

Intervertebral joints find crucial support from ligaments, which are tough and inelastic fibers. These hold the spine together by allowing a limited range of movement in any one direction. Ligaments require regular activity and stretching; otherwise they will eventually stiffen and weaken.

Summary

• There are 24 vertebrae in your back, protectively encasing your spinal cord.
• Critical nerves in your spinal cord run through each vertebral joint in your spinal column.
• Your discs function as shock absorbers.
• Discs depend on absorption for their nutrients.
• Muscles and ligaments need regular stretching in order to effectively support your back.