Basic Anatomy of the Knee – Ashley Johnston AEP

The knee joint is a hinge joint where the femur (thigh bone) and tibia (shin) meet. The final component of the knee is the patella (knee cap). The knee is then held together by the connective tissue,  ligaments and muscles.  

The ligaments provide stability to the knee. There are four main ligaments of the knee.  

  • The anterior cruciate ligament
  • The posterior cruciate ligament  and
  • The medial and lateral collateral ligaments

There is then the 2 pieces of cartilage called the medial and lateral menisci that can act as shock absorbers between the femur and tibia.  

The main movement that the knee goes through is flexion and extension. Flexion is the bending of the knee whereas extension of the knee is the straightening movement. Muscles help to facilitate the movement. The main muscles involved are below: 

  • Flexion- Semitendinosus, Semimembranosus, Biceps Femoris ( these three muscles make up the hamstring), Gracilis, Sartorius, Popliteus   
  • Extension- Quadriceps Femoris made up of vastus lateralis, vastus medialis, vastus intermedius and rectus femoris

The knee is also able to move through some internal and external rotation. The muscles that are involved in these movements are 

  • External Rotation– Biceps Femoris (vastus lateralis, vastus medialis, vastus intermedius and rectus femoris), and Gastrocnemius  
  • Internal Rotation-  Semitendinosus, Semimembranosus, Biceps Femoris (these three muscles make up the hamstring) Gracilis, Sartorius, Popliteus, Gastrocnemius. 

Each of these components of the knee can sustain an injury. No one injury is the same, however there are activities that you can do  to maintain your general knee health and stability. Some of the foundation exercises that you can do are  

  • Bridge
    • Lie on your back with your hands at your sides, knees bent, and feet flat on the floor
    • Brace your abdominal (draw your belly button towards your spine) and squeeze glute muscles
    • Raise your hips to create a straight line from your knees to shoulders. 
    • Hold for 20 to 30 seconds, and then return to your starting position.
    • Keep your knees outs throughout  
    • Complete at least 10 reps. 
  • Squats –  basic body weight squat
    • Stand feet slightly wider than hip width apart 
    • Arms in front of body 
    • Sit back and descend into a balanced squat position, pause, return to standing by pushing up through heels and squeeze bottom
    • Ensure squatting action is pain free 
    • Feet stay flat on the floor 
    • Move slowly through the action 
    • Sets and Reps can be determined on a individual basis e.g 2 sets 8 reps
  • TKE (terminal knee extension) –   
    • Loop band around support and anchor just above the knee 
    • Stand in small split stance with band around the back leg
    • Keeping support leg still, bend and extend working knee, focusing on the extension phase  
    • Straighten the knee as much as possible and tense your thigh, pause
    • Repeat on opposite leg 
    • Sets and Reps can be determined on a individual basis e.g 2 sets 10 reps