Bone and Body Basics


Research has demonstrated that when individuals have poor bone strength movements, whether they are moves associated with exercise or household chores, that incorporate a forward “slouching” of your back, will, over time, lead to compression fractures of your spine.

When you slouch forward, the weight of your head and upper body is transferred to the front of your vertebral body instead of being evenly distributed through your entire vertebral body. This concentration of weight on the front of your vertebral body can cause little fractures or micro fractures. With each micro fracture, your vertebral body weakens until eventually it collapses. The collapse of your vertebral body is known as a vertebral compression fracture.

Vertebral compression fractures can lead to a rounding of your upper back and a loss of height – making digesting food, eating, and breathing difficult. It also affects your balance and could lead to an increased risk of falling.

Vertebral compression fractures are the most common type of all osteoporotic fractures . They often go undetected because the back pain associated with them may eventually diminish. Unfortunately, what most people do not realize is that once they have one compression fracture, their risk of another goes up significantly unless they learn to move and exercise in a manner that supports their spine. Unless intervention occurs with the right type of exercises, an individual who has experienced one vertebral compression fracture will be at significant risk for more vertebral fractures.

The Vertebral Structure
The human spine is an incredible pillar made up of vertebrae – all held together by discs, ligaments, and muscles.

There are twenty-four vertebrae in the spine. Most people have seven vertebrae in their neck known as cervical vertebrae, twelve vertebra in their mid-torso known as thoracic vertebrae, and five vertebra in the low back known as lumbar vertebrae.

Figure 1

Figure 1 , to the right, identifies the location of the different vertebrae in the spine.

The vertebral body is the weight-bearing part of your vertebrae. It is composed of two types of bone tissue: cortical and cancellous. Cortical bone is rigid and forms the hard outer layer of your vertebral body. Cancellous bone fills the inner cavity of your vertebral body and is porous in nature.

Cancellous bone is also referred to as trabecular or spongy bone. The inside of the cortical bone is supported by trabecula – the scaffolding structure within the cortical bone. The space between individual trabecula is the storage house for red and yellow marrow.

The thoracic vertebrae (located in the middle of the back) have the highest proportion of cancellous bone.

Figure 2

Figure 2, left, illustrates how the cortical and cancellous components make up a vertebral body.

In the upper magnified view, the cancellous bone tissue in the normal bone (represented by the light or white color) is quite dense and is able to provide support for the vertebral body.
(Note that the absence of bone tissue in the two circles is represented by the dark or black regions, while the presence of bone tissue is represented by the light or white areas.)

In the lower magnified view of the osteoporotic bone, the cancellous bone tissue is more porous. Individual trabecula have become thinner and, in some cases, have disappeared altogether.

The risk of fracture for the osteoporotic vertebra, in the lower part of Figure 2 , has increased (as compared to the vertebral body of the normal bone) because it has a lower number of cross-linking trabecula and a thinner honeycomb structure.

Our bone density peaks when we reach around 30 years of age. After that, our bone density starts to decrease. As bone density within the skeleton is lost, it is lost at a faster rate in cancellous bone. As a result, the vertebral body – composed largely of cancellous bone – is at an elevated risk of fracturing.