scar tissue
Meaning of scar tissue: Repair rather than regeneration: the body trades the original structure for a fast patch that holds, and the trade is permanent.
Definition of scar tissue
Scar tissue is the dense fibrous material the body lays down to close a wound, built largely from collagen packed in parallel bundles rather than the woven pattern of normal tissue. It seals and holds, but it does not reproduce what was lost. Sweat glands, hair follicles, fine nerve endings and elastic fibers are not rebuilt within it.
How does it form?
Healing runs in overlapping stages. Bleeding stops first, then inflammatory cells clear debris and bacteria. Within days, cells called fibroblasts move in and secrete collagen, the rope like protein that gives connective tissue its strength. New capillaries grow into the soft red material that results, and the surface closes over it. Then comes the long stage most people never notice: over months the collagen is broken down and relaid, the excess vessels regress, and a red raised ridge fades to a pale flat line. A wound that looks healed in a fortnight is still being remodeled a year later.
Why is it weaker than what it replaces?
Normal skin holds its collagen in a basket weave that resists pull from any direction. Scar collagen lies in parallel bundles laid along the line of tension, quick to build but strong mainly in one direction. The tissue also lacks elastic fibers, so it does not stretch and spring back. Repaired tissue never regains the full strength of the original, and that shortfall is why an old surgical site stays the weakest point in an abdominal wall.
What forms can it take?
| Form | What happens |
|---|---|
| Fine line scar | Collagen remodels well and the mark flattens and pales |
| Hypertrophic scar | Excess collagen stays raised but within the original wound edges |
| Keloid | Growth continues past the wound edges into untouched skin |
| Contracture | The scar shortens as it matures, pulling a joint or eyelid out of position |
| Adhesion | Internal bands stick organs together, most often after abdominal surgery |
| Fibrosis | Scarring spreads through an organ, as in the liver or the lung |
Which of these follows an injury depends on tension across the wound, its depth, the site on the body and inherited tendency, far more than on how large the original injury was. The same cut across a shoulder and along a wrinkle line heals to two different marks.
Also known as
Used in a sentence
Dense scar tissue from the previous operation obscured the plane of dissection.
Good to know
Scar tissue contains no hair follicles, sweat glands or elastic fibers, and its collagen lies in parallel rather than woven bundles, so the repaired area stays stiffer and weaker than what it replaced.
Word origin
Where “scar tissue” comes from
Scar reached English through Old French from the Greek eskhara, a scab; tissue comes from the Latin texere, meaning to weave.