Anterior cruciate ligament facts for kids

The anterior cruciate ligament (say: an-TEER-ee-or CROO-shee-ate LIG-uh-ment), often called the ACL, is a very important band of tough tissue inside your knee. It's one of four main ligaments that help keep your knee stable. Think of ligaments like strong ropes that connect bones. The ACL connects your thigh bone (femur) to your shin bone (tibia).

What is the ACL?

The ACL is located deep inside the knee joint. It runs diagonally from the back of your thigh bone to the front of your shin bone. Its main job is to stop your shin bone from sliding too far forward. It also helps prevent your knee from twisting too much. This is super important for movements like running, jumping, and changing direction.

Why is the ACL Important?

Your knee is a complex joint that allows you to bend, straighten, and slightly rotate your leg. The ACL works with other ligaments to make sure your knee moves correctly. Without a healthy ACL, your knee can feel wobbly or unstable. This can make it hard to do everyday activities, let alone play sports.

What Happens When the ACL Gets Hurt?

Injuries to the ACL are very common, especially among athletes. These injuries often happen when someone suddenly stops, changes direction, or lands awkwardly from a jump. Moving the knee sideways or rotating it too much can also cause the ACL to stretch or tear.

Types of ACL Injuries

ACL injuries can range from a mild stretch to a complete tear.

• Sprain: This is when the ligament is stretched but not torn. It might feel a little sore.
• Partial Tear: Part of the ligament is torn, but some fibers are still connected.
• Complete Tear: The ligament is torn into two pieces. This is the most serious type.

Signs of an ACL Injury

If you injure your ACL, you might hear a "pop" sound in your knee. You might also feel immediate pain and swelling. It can be hard to put weight on your leg. Your knee might feel unstable, like it's going to give out.

How Are ACL Injuries Treated?

If an ACL is completely torn, it almost always needs surgery to fix it. This is because the ACL doesn't heal well on its own.

• Surgery: During surgery, a doctor replaces the torn ACL with a new piece of tissue. This new tissue often comes from another part of your body, like your hamstring or patellar tendon. Sometimes, it can come from a donor.
• Rehabilitation: After surgery, you'll need to do physical therapy. This helps you get your strength, movement, and balance back. It's a long process, but it's important for getting back to your activities.

Preventing ACL Injuries

While not all injuries can be prevented, there are ways to lower your risk.

• Warm-up: Always warm up properly before playing sports.
• Strength Training: Strengthen the muscles around your knee, especially your hamstrings and quadriceps.
• Proper Technique: Learn how to land from jumps and change direction safely. Many sports programs teach special exercises to help with this.

Images for kids

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  Right knee joint, from the front, showing interior ligaments

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  Left knee joint from behind, showing interior ligaments

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  Head of right tibia seen from above, showing menisci and attachments of ligaments

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  Capsule of right knee-joint (distended), posterior aspect

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  MRI shows normal signal of both cruciate ligaments (arrows)

See also

In Spanish: Ligamento cruzado anterior para niños