ACL Anatomy
There are three bones that make up the knee joint – the femur (thigh bone), the tibia (shin bone), and the patella (kneecap). There are two cruciate ligaments—Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL)—inside the knee joint that cross to form an X. The ACL sits in the front of the knee joint, while the PCL sits in the back of the knee joint. Together, they help control the front-to-back motion of the knee, as well as rotation.
The ACL is one of two cruciate ligaments in the knee joint that cross to form an X. It is a vital structure that helps stabilize the knee and control its movement. The primary function of the ACL is to prevent excessive forward movement of the tibia relative to the femur, as well as controlling rotational movements of the knee. It works in conjunction with other ligaments and structures in the knee to provide stability and support during activities like walking, running, jumping, and pivoting.
The purpose of the ACL ligament is to prevent the tibia from sliding in front of the femur. The ACL also acts to stabilize the knee during rotation. The ACL runs diagonally from the back of the femur to the front of the tibia in order to provide this stability. The ACL ligament contains important nerve fibers that tell your brain where your knee is positioned, as well as vessels that help with the overall nutrition of the ACL.
At a Glance
Dr. Jorge Chahla
- Triple fellowship-trained sports medicine surgeon
- Performs over 800 surgeries per year
- Associate professor of orthopedic surgery at Rush University
- Learn more
