Deformations experienced in the human skin, adipose tissue, and fascia in osteopathic manipulative medicine.

CONTEXT: Osteopathic manipulative medicine techniques involve compressive and tangential forces to target the fascia. These forces are transmitted to the skin and adipose tissue before the fascia is encountered. Knowing the extent of deformation of these 2 tissue layers relative to the fascia will assist osteopathic physicians in evaluating techniques for manual therapies and adjusting these therapies to reduce patient discomfort and improve results. OBJECTIVE: To determine the magnitude of the forces transmitted to the skin, adipose tissue, and fascia, and to determine the magnitude of deformation produced in the skin and adipose tissue relative to the fascia using a mathematical model. METHODS: The large deformation theory of elasticity, valid for 3-dimensional deformations, was used to evaluate the forces that need to be applied such that a specified deformation is produced in any region of the skin, adipose tissue, or fascia layers. Similarly, if the forces are specified, then the deformation produced can be determined. RESULTS: The normal and tangential forces required to produce a deformation of 9% compression and 4% shear for the skin were 50 N and 11 N, respectively. Normal and tangential forces of about 100 N and 22 N were found for a similar deformation of fascia. For adipose tissue, these forces were 36 N and 8 N, respectively. In addition, the skin experienced more compression and shear-about 1.5 times as much as the fascia, and the adipose tissue experienced about 2.5 to 3.5 times the deformation of the fascia and 50% more than the skin when a given force was applied to the skin. CONCLUSION: The forces applied to the surface of the skin were transmitted through this layer and the adipose layer entirely to the fascia. Therefore, the skin and adipose tissue experienced the same magnitude of force as the fascia. However, the skin and adipose tissue experienced more compression and shear than the fascia.

Measurement of balance in computer posturography: Comparison of methods--A brief review.

Some symptoms related to disequilibrium may not be detected by a clinical exam. Therefore, objective study is important in assessing balance. In this paper, methods to measure balance in computer posturography are compared. Center of pressure (COP) displacement, equilibrium score (ES) and postural stability index (PSI), the main measures of assessing balance are described and their merits and disadvantages are discussed. Clinicians should apply that measure which suits the specific strategies in a specific situation. Measuring devices such as Force plate, Balance Master and Equitest are also discussed. Although the Balance Master and Equitest devices are more costly compared to the force plate only, they are more useful for assessing balance relevant to daily life activities that might result in falls.

Viscoelastic stresses on anisotropic annulus fibrosus of lumbar disk under compression, rotation and flexion in manual treatment.

BACKGROUND: Twisting (spinal rotation) and bending (flexion) are commonly reported as triggers for low back pain. This paper addresses whether the twisting stress on the annulus fibrosus of the lumbar disk is greater or less than the bending stress for the same angle of twist or bending. METHODS: Stress-strain relation for transversely isotropic material is applied to the transversely isotropic annulus fibrosus of the lumbar disk to analyze the viscoelastic stresses produced due to 6% compression, 10 degrees twist and 10 degrees bending. FINDINGS: The bending stress is 450 times greater than the twisting stress for the same angle of twist or bending of the annulus fibrosus. The twisting and bending moments increase two-fold in quick maneuvers lasting 0.1s (as in high velocity manipulations), compared to slow maneuvers lasting 60s. INTERPRETATION: From biomechanical perspective, in situations where both flexion and spinal rotation occur, the stress on the intervertebral disk is markedly higher with flexion compared to rotation. In patients with low back pain that has a disk mediated (discogenic) component, manipulation and mobilization therapies should avoid flexion to minimize stress on the disks. This is particularly relevant for high velocity manipulations where the stress on the disk is doubled for both flexion and rotation. The results in this paper can help guide manual therapists to adjust their treatments to minimize stress on the intervertebral disk.

Three-dimensional mathematical model for deformation of human fasciae in manual therapy.

CONTEXT: Although mathematical models have been developed for the bony movement occurring during chiropractic manipulation, such models are not available for soft tissue motion. OBJECTIVE: To develop a three-dimensional mathematical model for exploring the relationship between mechanical forces and deformation of human fasciae in manual therapy using a finite deformation theory. METHODS: The predicted stresses required to produce plastic deformation were evaluated for a volunteer subject's fascia lata, plantar fascia, and superficial nasal fascia. These stresses were then compared with previous experimental findings for plastic deformation in dense connective tissues. Using the three-dimensional mathematical model, the authors determined the changing amounts of compression and shear produced in fascial tissue during 20 seconds of manual therapy. RESULTS: The three-dimensional model's equations revealed that very large forces, outside the normal physiologic range, are required to produce even 1% compression and 1% shear in fascia lata and plantar fascia. Such large forces are not required to produce substantial compression and shear in superficial nasal fascia, however. CONCLUSION: The palpable sensations of tissue release that are often reported by osteopathic physicians and other manual therapists cannot be due to deformations produced in the firm tissues of plantar fascia and fascia lata. However, palpable tissue release could result from deformation in softer tissues, such as superficial nasal fascia.