Soft tissue
Soft tissue connects and surrounds or supports internal organs and bones, and includes muscle, tendons, ligaments, fat, fibrous tissue, lymph and blood vessels, fasciae, and synovial membranes.
[1] [1] It is sometimes defined by what it is not – such as "nonepithelial, extraskeletal mesenchyme exclusive of the reticuloendothelial system and glia".
The fibroblasts are the most common cell responsible for the production of soft tissues' fibers and ground substance.
Human soft tissue is highly deformable, and its mechanical properties vary significantly from one person to another.
[6] Soft tissues have the potential to undergo large deformations and still return to the initial configuration when unloaded, i.e. they are hyperelastic materials, and their stress-strain curve is nonlinear.
Some viscoelastic properties observable in soft tissues are: relaxation, creep and hysteresis.
These methods include: hyperelastic macroscopic models based on strain energy, mathematical fits where nonlinear constitutive equations are used, and structurally based models where the response of a linear elastic material is modified by its geometric characteristics.
[9] Even though soft tissues have viscoelastic properties, i.e. stress as function of strain rate, it can be approximated by a hyperelastic model after precondition to a load pattern.
After some cycles of loading and unloading the material, the mechanical response becomes independent of strain rate.
Despite the independence of strain rate, preconditioned soft tissues still present hysteresis, so the mechanical response can be modeled as hyperelastic with different material constants at loading and unloading.
Physiologists and histologists must be aware of this fact to avoid mistakes when analyzing excised tissues.
[8] Fung developed a constitutive equation for preconditioned soft tissues which is with quadratic forms of Green-Lagrange strains
, which is the positive root of Soft tissues have the potential to grow and remodel reacting to chemical and mechanical long term changes.
Mechanobiology is the science that study the relation between stress and growth at cellular level.
Other instance of tissue remodeling is the thickening of the cardiac muscle in response to the growth of blood pressure detected by the arterial wall.
There are certain issues that have to be kept in mind when choosing an imaging technique for visualizing soft tissue extracellular matrix (ECM) components.
Some techniques allow the direct acquisition of volume data while other need the slicing of the specimen.
[citation needed] Musculoskeletal specialists, manual therapists, neuromuscular physiologists and neurologists specialize in treating injuries and ailments in the soft tissue areas of the body.
[citation needed] A promising new method of treating wounds and soft tissue injuries is via platelet-derived growth factor.
