Composition and Mechanical Characteristics of Soft Tissue
- Soft tissue is composed of collagen, elastin, and ground substance.
- Fibroblasts are responsible for producing soft tissue fibers and ground substance.
- Elastin confers stiffness to the tissue, while collagen limits deformation and protects tissues from injury.
- Human soft tissue is highly deformable and its mechanical properties vary among individuals.
- Stiffness and damping resistance of soft tissue are correlated with the mass, velocity, and size of the striking object.

Pseudoelasticity and Residual Stress in Soft Tissue
- Soft tissues exhibit viscoelastic properties but can be approximated by a hyperelastic model after preconditioning to a load pattern.
- Preconditioned soft tissues still present hysteresis, so the mechanical response can be modeled as pseudoelastic.
- Soft tissues usually have residual stress in their physiological state, which may be released when the tissue is excised.
- Physiologists and histologists must be aware of residual stress to avoid mistakes in tissue analysis.

Remodeling and Growth of Soft Tissue
- Soft tissues can grow and remodel in response to chemical and mechanical changes.
- Fibroblasts produce tropocollagen at a rate proportional to these stimuli.
- Remodeling plays a role in soft tissue diseases, injuries, and changes in mechanical load.
- Growth and remodeling are involved in the thickening of cardiac muscle in response to increased blood pressure.
- Mechanobiology studies the relationship between stress and growth at the cellular level.

Imaging Techniques for Soft Tissue Visualization
- Choosing an imaging technique for visualizing soft tissue extracellular matrix (ECM) components requires considering factors such as resolution, contrast, artifact count, and volume data acquisition.
- Transmission Light, Confocal, Multi-Photon Excitation Fluorescence, Second Harmonic Generation, and Optical coherence tomography are different imaging methods with varying properties and resolutions.
- The resolution of the imaging technique needs to be approximately 0.5 μm to capture the 1-2 μm thick collagen fibers.
- Volume data acquisition allows following fiber bundles across the volume.
- Fixation of soft tissue in formalin can cause shrinkage and alter the tissue structure.

Soft Tissue Disorders and Sarcomas
- Soft tissue disorders affect soft tissues in the body and can be difficult to treat and diagnose.
- Soft tissue therapy is an expanding field, and platelet-derived growth factor shows promise in treating soft tissue injuries.
- Soft tissue disorders and rheumatism have overlap, and soft tissue rheumatic disorders is a term used to describe these conditions.
- Rheumatologists specialize in treating soft tissue rheumatic disorders, which can cause chronic pain and difficulty in diagnosis.
- Soft tissue sarcomas are types of cancer that develop in soft tissues and can occur in various parts of the body.
- Diagnosis of soft tissue sarcomas involves imaging and biopsy, and treatment options include surgery, radiation, and chemotherapy.
- The prognosis for soft tissue sarcomas depends on various factors.