Knee Outline
Jan 17, 2016
Knee Outline
Bones of the Knee
• Femur- thighbone, largest and hardest bone in body
• Tibia- largest lower leg bone. Distal end forms medial malleolus
• Fibula- smaller lower leg bone. Non-weight bearing. Distal end forms lateral malleolus.
• Patella- kneecap. Largest sesmoid bone.
Anterior Muscles of the Knee Joint
• Quadriceps Group ( 4 )- “ Body’s own Natural Knee Brace”
• Rectus Femoris- Longest and most anterior. Knee extension and Hip flexion.
• Vastus Intermedius- Deepest Quad. Muscle. Underneath Rectus Femoris, knee extension.
• Vastus Lateralis- On the lateral side of the thigh. Knee extension.
• Vastus Medialis- Most medial on thigh. Forms the bulge above medial side of the knee. Knee extension.
Anterior Muscles of the Knee Joint cont.
• Sartorius-Located on the medial aspect of the thigh, from center of thigh to the medial side of the knee.
• Gracilis- “ Groin Muscle” On the medial aspect of the thigh. Adduction of hip & flexion of knee
Posterior Muscles of the Knee Joint
• Hamstrings Group ( 3 ) located posteriorly
– Semitendinosus- On the medial aspect of the thigh. Knee flexion & medial rotation.
– Biceps Femoris- Lies lateral to Semitendinosus. Knee flexion & lateral rotation.
– Semimembranosus- On top of # 1 & # 2. Knee flexion & medial rotation.
Sem
iten
din
osu
s
Bic
eps
Fem
ori
s
Sem
imem
bra
no
sus
Distal Muscles of the Knee Joint
• Popliteus-On the back of the knee from upper lateral to lower medial. Knee flexion & medial rotation of flexed leg.
• Gastrocnemius- “Calf Muscle” Split in two sections. Knee flexion.
• Plantaris- From upper lateral knee to medial malleolus. Ankle plantar flexion, & Knee flexion.
Side Ligaments of the Knee
• Medial Collateral Ligament ( MCL )-on medial side of the knee, broad flat ligament. Secures femur to the tibia. Most injured ligament.
• Lateral Collateral Ligament ( LCL )- on lateral side. Cord-like shaped ligament. Secures femur to Fibula.
Inside Ligaments of the Knee
• Anterior Cruciate Ligament ( ACL )- attaches on the front ( anterior ) aspect of the tibia, runs up and back to the posterior aspect of the femur. Controls anterior movement of the tibia under the femur.
• Posterior Cruciate Ligament ( PCL )- attaches to the front ( anterior) aspect of the femur, runs down and back to the posterior aspect of the tibia. Controls posterior movement of the tibia under the femur.
Cartilage of the Knee
• a.k.a. menisci
• Medial Meniscus- forms a ½ moon shaped cushion base for the medial femoral condyle. The head of the femur.
• Lateral Meniscus- forms almost oval shaped cushion base for the lateral femoral condyle.
R. O. M. of the Knee
• Flexion- bending the knee
• Extension- straightening the leg