1. Tissue Response to Injury

2. Soft Tissue Injuries All tissue injuries other than bone
Types of injuries to skin
Abrasion
Laceration
Puncture
Incision
Avulsion

3. Signs of Injury
Developed by roman physician Celsus in the first century
Redness
Swelling
Heat
Pain
Loss of function

4. Phases of Injury Inflammatory Response phase Repair phase
Remodeling phase

5. Inflammatory Phase Inflammatory response
Acute vs. chronic
Cellular vs. vascular
First 3-4 days following an injury
Designed to protect, localize, and rid the body injurious agent in preparation for repair

6. Acute Inflammation Tissue death results from the trauma
Following trauma tissue death results from a lack of oxygen at cellular level
First hour vasoconstriction occurs
Coagulation of vessels to seal broken blood vessels
Platelet plug
Second hour vasodilation
↑ swelling secondary to ↑ viscosity of blood and stasis
Margination occurs
Diapedesis
Phagocytosis

7. Acute Inflammation Chemical reactions
Histamine given off by blood platelets, basophils, and mast cells causes arterial dilation
Bradykinin increases permeability and causes pain
Seratonin causes a vasoconstriction
Prostaglandins and leukotrienes cause vasodilation
The extent of the fluid in the area is dependent on the extent of the damaged vessels and the permeability of the intact vessels
With the blood coagulation the plasma coagulates into a network of fibrin which localizes the injured area

8. Repair Phase Time frame 48-72 hours to 6 weeks
Repair (healing) and regeneration (restoration) take place
Three things for healing to occur
Occurs when the area is clean of cellular debris (phagocytosis)
Regeneration of cells to reestablish capillary blood flow
Production of fibroblasts

9. Repair and Regeneration
Primary and secondary healing
Primary is healing by intention with even and closely opposed edges
Secondary results when gapping lesions and large tissue loss leading to replacement by scar tissue

10. Remodeling Phase Overlaps with the repair and regeneration phase
Time frame 3 weeks up to 2 years
Strength of scar tissue continues to increase over time
Ligaments take as long as one year to become completely remodeled
To avoid rigid unyeilding scars you must have a balance between lysis (breaking down) and synthesis (building up)

11. Reasons for Rehabilitation
The tensile strength of collagen is specific to the mechanical forces applied during the remodeling phase
Strength will be developed specifically in the direction that is applied
If done too early or excessive the healing process is extended