It seems as if every time I open the sports section lately, another star athlete has been sidelined with a knee injury. To name a few: Indianapolis Colts wide receiver Anthony Gonzalez is out for two months, Chicago Cubs outfielder Alfonso Soriano is done for the season, and Dallas Mavericks forward Tim Thomas is prepping for surgery.

But unless you’re an expert, reading that your favorite player has suffered a knee injury is not just upsetting – it’s confusing! What’s the different between a sprained ligament and a torn cartilage? How about ACL versus PCL? I decided to look into some common terminology to better understand all the different knee injuries

Many athletes fall victim to ligament injuries. Ligaments connect your thighbone to your lower leg bones, holding the knee in place. There are two classes of ligaments, the cruciate ligaments and the collateral ligaments. The cruciate ligaments, located inside your knee joint, control the knee’s front and back motions. The collateral ligaments, located on the sides of your knee, are in charge of sideways motion. Injured ligaments are called “sprains,” and they are ranked on a scale of one to three, with grade three sprains being the most damaging.

Cruciate Ligaments – ACL and PCL

The two types of cruciate ligaments are anterior (ACL) and posterior (PCL). ACL injuries are some of the most common; the American Academy of Orthopaedic Surgeons estimates that 200,000 ACL injuries occur per year. The majority of these injuries do not require any direct contact. A quick deceleration, abrupt change in direction or awkward landing is enough to cause a sprain. Athletes most at risk for an ACL injury are skiers or those who play basketball, soccer or football.

PCL injuries often result from a powerful, direct blow to the knee; for example, a football player falling on a bent knee. Athletes can also injure theirs PCLs by over-stretching the ligament or making a misstep on the playing field.

Collateral Ligments – MCL and LCL

The two types of collateral ligaments are medial (MCL) and lateral (LCL). The MCL is injured more often than its lateral counterpart. This type of sprain is caused a direct blow to the knee that pushes it sideways. As a result, MCL injuries occur most often in contact sports, such as football or soccer.

Meniscus

Ligaments are not the only parts of the knee at risk for injury. The meniscus, the rubbery cartilage in your knee, is another common injury site. Located between your thigh and shin bones, the meniscus acts as a shock absorber for your knee, keeping it stable.

Tears in the meniscus can occur when athletes twist or pivot their knee, or during tackles. If you hear someone has torn their cartilage, it most likely means they have torn their meniscus.