• [On-Line Movie: Degeneration of Disc (= Disc Lesion) (avi)]

    •
    Biomechanics of Lower Back
    and
    Intervertebral Disc

  • The intervertebral disc cartilages (DISCs) are the structure which fits between the vertebral bones (vertebrae, or back bones). They act as shock absorbers that cushion the spainal column. They enable the spine to bend in all directions.
  • A disc is made of two parts;
    [ANATOMY]
  • The outer casing is strong and resilient; and is made of crisscrossing fibrous layers like a Kevler radial tire. The inner nucleus is a gelatinous substance that provides shock absorber mechanism of the discs, which can be likened to a balloon that changes shape when compressed, but returns to its original contour when pressure is reduced. Discs are always under certain pressure due to the fact that gravity acts on the mass of the body, and para-vertebral muscles continuously constract to maintain posture. When in balance with the normal spinal curves of good posture, the discs and other spinal structures are under the least amount of mechanical stress (Fig.2).
    [POSTURE]
  • Most of acute low back pain originates from the discs and surrounding tissues. These troubles may occur as a result of poor body mechanics or simply by the aging process. Discs contain about 80-90% water of the weight. As you age the water content is reduced and, therefore, flexibility of the annulus (outer casing) is diminished. Stretching, cracking, and tearing of the outer casing becomes more likely with certain body motions and positions (avi.MOVIE). Namely bending and tensile forces acting on the spinal column must be controlled, and torsional force should be eliminated to protect discs from injury.

    [Movie: MAKING OF HERNIA]gif.ANIME

  • In everyday life, we spend a lot of time in the flexed (bent-forward) position, which may cause pressure on our discs and keeps them compressed for long periods. This continuous repetitive activity strains the annulus (outer casing) putting it under extreme pressure, which can lead to tear and pain.
  • The annulus (outer casing) can weaken, causing a bulge and/or balloon, or even a rupture where the gelatinous nucleus (inner core) can leak out into the surrounding tissues (herniation)(Fig.3).
    [HERNIATION]
  • By maintaining neutral or pelvic tilt posture, we can reduce the excess curve in our lower back and diminish the intra-disc pressure. This technique will prolong the life of the disc system and reduce inflammation and pain.
  • Our natural aging process cannot be stopped, however, we can prevent extra damage to the discs by correcting bad habits and maintaining proper posture, those may prevent unnecessary back pain. Be fit. Strengthened abdominal muscles function as lumbar brace or corset (by theory) (Fig.4).

    [MUSCLE]

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