A strain refers to what kind of injury?

A strain specifically refers to an injury that involves the stretching or tearing of muscles or tendons. Muscles are responsible for movement, and tendons connect muscles to bones. When a muscle is overstretched or subjected to a forceful contraction, it can lead to a strain, which often causes pain, swelling, and limited mobility in the affected area.

The other options refer to different types of injuries. The first option describes injuries to bones, which would not be categorized as a strain. The third option pertains to ligaments, which are connective tissues that link bones to other bones, and injuries associated with ligaments are known as sprains. The fourth option relates to closed head trauma, which involves injuries to the head and brain but does not fall under the definition of a strain. Understanding these distinctions helps clarify why the correct answer focuses on the muscles and tendons as the sites of injury associated with a strain.