The Knee Joint

Anatomy and Physiology of Human Movement

420:050

Objectives

Bones, bony landmarks and joints Muscles Movements

Knee Joint Large joint Complex ligamentous structures Femoral condyles articulate with tibial condyles Medial/lateral tibial condyles (aka plateaus) – act

as receptacles for femoral condyles Relatively stable joint despite injuries

Ligaments Menisci Quadriceps and hamstrings

Modified from Anthony CP, Kolthoff NJ: Textbook of anatomy and physiology, ed 9, St. Louis, 1975, Mosby.

Modified from Anthony CP, Kolthoff NJ: Textbook of anatomy and physiology, ed 9, St. Louis, 1975, Mosby.

Bones and Bony Landmarks Tibia:

Bears weight Fibula:

Serves as the attachment sight Does not articulate with femur or patella Not part of knee joint

Patella: Sesamoid bone imbedded in patellar tendon Improves mechanical advantage in knee extension

Bony landmarks same as the hip joint

Lateral femoral epicondyle Medial femoral

epicondyle

Patella

Tibial tuberosity

Head of fibula

Lateral tibial condyle

Medial tibial condyle

Joint Knee joint

Diarthrodial uniaxial hinge joint Movements Planes and axes

Patellofemoral joint Diarthrodial nonaxial gliding joint Gliding nature of patella on femoral

condyles

Objectives

Bones, bony landmarks and joints Muscles Movements

Muscles Quadriceps

Rectus femoris Vastus medialis Vastus lateralis Vastus intermedius

Hamstrings Biceps femoris Semimembranosus Semitendinosus

Sartorius Gracilis Popliteus Gastrocnemius

Rectus Femoris

Vastus Medialis

Vastus Lateralis

Vastus Intermedius

Biceps Femoris

Semimembranosus

Semitendinosus

Sartorius

Gracilis

Popliteus

Gastrocnemius

Objectives

Bones, bony landmarks and joints Muscles Movements

Movements

Flexion Bending or decreasing angle

between femur and shin Extension

Straightening or increasing angle between femur and shin

Movements

External rotation Rotary movement of leg laterally

away from midline Internal rotation

Rotary movement of lower leg medially toward midline

Neither will occur unless flexed 20-30 degrees or more

LINE OF PULL

FLEXION

Bending or decreasing angle between femur and shin

Popliteus

FLEXION

FLEXION

Biceps femoris Semimebranosus Semitendinosus Sartorius Gracilis Popliteus Gastrocnemius

EXTENSION

Straightening or increasing angle between femur and shin

EXTENSION

EXTENSION

Rectus femoris Vastus lateralis Vastus medialis Vastus intermedius