The Anatomy of the Knee

The knee is a hinge joint formed by the tibia (shinbone), femur (thighbone) and patella (kneecap). The ends of the bones in the joint are covered with cartilage a tough lubricating tissue that helps cushion the bones during movement.

Diagram 1: The Human Knee

The Joints

The joint mainly allows for bending (flexion) and straightening (extension) of your knee. The knee joint consists of two articulations-tibiofemoral and patellofemoral. The joint surfaces are lined with cartilage, and are enclosed within a single joint cavity.

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 Tibiofemoral (Knee joint)-medial and lateral condyles of the femur articulate with the tibial condyles. It is the weight-bearing component of the knee joint.

 Patellofemoral (kneecap)-(Anterior) aspect of the femur at the knee joint articulates with the Patella. It allows the tendon of the quadriceps femoris (muscle that extends knee) to be inserted directly over the knee-increasing its efficiency.

The Ligaments

There are a number of ligaments related to the knee. However the main ones are the collateral and the cruciate ligaments. These ligaments work to stabilise the knee and give the knee its awareness of its position in space.

The Muscles

Diagram 2: The 'Knee' Muscles

The main muscles of the knee joint consist of two groups that work together to extend and flex the knee joint during activities such as walking and running.

The muscles at the front of the thighs are called the quadriceps. They are a group of four muscles which work to extend or straighten the knee. They attach to the shin bone by a thick tendon called the Patellar tendon.

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At the posterior aspect of the thigh are a group of three muscles called the Hamstrings. They work together to flex the knee during activities.

These are the main muscles which directly control the knee. However other muscles such as the gluteal muscles are important to help control the position and alignment of the knee. Remember general muscle conditioning is also important!

Menisci

The menisci are C-shaped tissues inside the knee joint, located between the thigh (femoral) and shin (tibia) cartilage surfaces. Both are found in the joint. There is one on the inside of the knee (medial) and one on the outside (lateral).

Diagram 3: Anterior of Knee Showing Medial and Lateral Menisci

The outer parts have adequate blood supply, but the middle and inner parts have poor blood supply. Because blood supply can affect healing, the location of a tear will affect treatment options.

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What does the Meniscus do in Your Knee?

The menisci are tissues that respond to the forces and loads that you put into the knee. They have several important functions:

 Shock absorption  Load Transmission (spreading weight more evenly into the knee joint  Increasing knee joint stability  Joint Lubrication

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