sprain or strain body anatomy

Sprain or Strain?

In Physical Therapy, Sports Injuries by Advance TherapyLeave a Comment

by Brian Allred
Often people ask what the difference between a sprain and a strain is. To answer it, we need a little bit of an anatomy lesson.

The body is full of moving parts and that means that we need structures that cause movement and structures that prevent movement in ways that we don’t want. Two of those structures are tendons and ligaments


Tendons are the connective tissues that connect muscles to bones to transform the movement from contracting muscles to moving bones—and of course the rest of the body parts that are connected to those bones. 


Ligaments are the connective tissues that connect bones to other bones. They allow joints to move in the direction that we want, but prohibit motion in other directions. For example, two of the ligaments at the knee are the MCL and the LCL which allow the knee to bend and straighten without moving side-to-side. You’ve probably seen a video of a football player take a hit to the knee and suddenly their knee DOES move side-to-side. That’s obviously a problem and that brings us back to sprains and strains.

In the example of the football player, he probably tore one of those ligaments that is supposed to prevent that motion. That’s called a sprain. Now a sprain doesn’t have to be a complete tear of a ligament. More often, it’s a partial tear, maybe even just on a microscopic level. A strain is very similar, but instead of a tear of a ligament, it is the tear of a tendon or muscle. Just like sprains, there are different degrees of strains where it could be micro-tears or a complete rupture or anything in between.

Simply put, the difference between a sprain and a strain is just a matter of what structure is injured:

Sprains —> ligaments

Strains —> tendons and muscles


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