Although your knee may seem like a simple hinge joint that swings back and forth as you go about your daily routine it is really one of the most complex joints in the body. Looking beneath the skin there are many different muscles coming from several directions that make your knee work. They not only move your knee but also help to stabilise it. Many of these muscles start off at your hip and pelvis above to the lower thigh bone, knee cap, shin bone and fibula. For convenience muscle groups can be classified as anterior (front) extensors, posterior (back) flexors, medial (inner), adductors and lateral (outer) abductors.

Anterior - Quadriceps are down the front of the thigh. These muscles extend the leg by straightening the knee.

Posterior - Hamstrings are a group of muscles that start at the back of the pelvis on the bit of bone that you sit on. They attach down at either side of top of the shin bone. These muscles flex or bend the knee.

Another important muscle at the back of the knee is the popliteus.

Medial - Adductors are made up of four parts. They pull the leg inward towards the other knee. They start at the pubic bone and attach at different heights along the inside of the thigh bone.

Other muscles that oare on the inner side of the thigh are called the sartorius and gracilis. They attach from the pelvis to the inner aspect of the lower knee.

Lateral - Tensor fascia lata runs down the outer leg (down the seam of your jeans). It starts at the side of the pelvis and attaches down below the knee.

The lower end of the muscle is called the Iliotibial Band.