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

http://en.wikipedia.org/wiki/File:Anterior_Hip_Muscles_2.PNG

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.

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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