My son tore the rotator cuff in his right shoulder. The doctor called this a “medium” tear. What does this mean?

Four tendons around the shoulder joint make up what is called the rotator cuff. Overuse or trauma can lead to injury of one or more of these tendons. The tears can be graded from mild to moderate to severe. Another way to say this is “small,” “medium,” and “large.”

Doctors rely on magnetic resonance imaging (MRI) to make this decision. A small or mild tear is less than ¼ inch (less than one centimeter). A medium or moderate tear is from ¼ to ¾ inches long (one to three centimeters). A large or severe tear is longer than ¾ of an inch (three to five centimeters).

Another way to look at this is whether or not the tear goes all the way through the tendon. Using this method, there are two kinds of tears: partial-thickness and full-thickness. A small or medium tear goes through part, but not all, of the tendon. A severe tear extends through the entire (full-thickness) of the tendon.