These movements result in various forces acting on the lumbar spine and sacrum: compressive force, tensile force, shear force, bending moment and torsional moment.
What are the three forces acting on human spinal disc?
Loads on the human spine are produced by (1) gravitational forces due to the mass of body segments, (2) external forces and moments induced by a physical activity, and (3) muscle tension. These loads are shared by the osseoligamentous tissues and muscles of the spine.
What force places rotation forces on the spine?
In a conventional dead-lift where you’re more inclined or bent-over, there will be more shear force. Torsion forces are more associated with rotational exercises occur when one vertebrae is rotating on top of the one below it.
What action occurs in the spine?
For the vertebral column, flexion (anterior flexion) is an anterior (forward) bending of the neck or body, while extension involves a posterior-directed motion, such as straightening from a flexed position or bending backward.
How many discs do you have in your spine?
It is a cushion of fibrocartilage and the principal joint between two vertebrae in the spinal column. There are 23 discs in the human spine: 6 in the cervical region (neck), 12 in the thoracic region (middle back), and 5 in the lumbar region (lower back).
What is between the discs in your spine?
Between each vertebra is a shock-absorbing disc that prevents the bones from rubbing together. Discs are designed like a radial car tire. The tough outer wall, called the annulus, has crisscrossing fibrous bands, much like a tire tread. These bands attach to each vertebra bone.
What is Spinal shearing?
Shearing is where the vertebrae are pulled forward* relative to each other. *The discs don’t actually slip and slide between the vertebrae, a slipped disc isn’t accurate of what actually happens with a disc injury but on a more subtle scale this is effectively what is happening within the spine.
What are the primary movements of the spine?
The 3 movements in the spine are flexion, extension, rotation and lateral flexion. These movements occur as a combination of rotation and translation in the following 3 planes of motion: sagittal, coronal and horizontal.