What term describes a tear of collagen fibers within a ligament?

The term that describes a tear of collagen fibers within a ligament is "sprain." A sprain specifically refers to the stretching or tearing of ligaments, which are the fibrous connective tissues that connect bones to one another at a joint. When these collagen fibers are torn, it results in the instability of the joint and is often accompanied by pain, swelling, and decreased range of motion.

In contrast, a strain refers to an injury to a muscle or tendon, which connects muscle to bone. Rupture is a more generalized term that can describe a complete tear or separation and can apply to various types of tissues, including muscles, tendons, and ligaments. The word "tear" can also describe a broader range of injuries and is not specific to ligaments, making it less precise than "sprain" in this context. Thus, "sprain" is the appropriate term for describing a ligament injury where collagen fibers are torn.