knee

complex joint

supported and mainted byu muscles and ligaments

lacks bony stability

exposed to severe stresses and strains

one of the most injured joints in the body

largest joint in the body

• synovial hinge joint
• not a true hinge
• has a rotational component
• accompanies other motions

motions

• flexion-120-135
• extension 0

• medial femoral condyle longer than lateral condyle
• as extension occurs, the articular surface of lateral condyle used up while 1/2" remains medially

therefore the medial condyle must glide posteriorly to use all of its articular surface

with knee extension in a non-weight bearing (NWB) position the femur rotates medially on the tibia

• closed chain-foot on the floor
• femur rotates medially/internally on the tibia

open chain=foot not on the floor

tibia roatates laterally/externally on the tibia

• head
• neck
• greater trochanter
• lesser trochanter
• body
• medial condyle
• lateral condyle

• medial lateral condyle
• tibial plateau
• intercondylar eminence
• tibial tuberosity'
• crest
• medial malleolus(inside ankle bone)

• lateral to and smaller than tibia
• posterior to tibia
• not part of the knee joint
• NO articulation with femur
• larger role at ankle

• patella
• tibia
• fibula
• fibular head
• lateral malleolus
• calcaneus

triangular shaped sesamoid bone

within quadriceps muscle tendon

broad superior border

distally somewhat pointed

articulation between the femur and patella

• patella's functions:
• increases mechanical advantages of quadriceps muscle
• protect knee joint

• angel between:
• quadriceps muscle (rectus femoris
• patellar tendon

• draw a line from anterior superior iliac sping to midpoint of the patella
• normal angle ranges 13-18
• Q angle> in females

related to many different knee & patellar problems-pain

• knee held together by ligaments and muscles
• ligaments
• cruciates-crossing ligaments
• collaterals
• menisci
• bursa
• popliteal space
• pes ansenine(gooses foot)
• sartorius, gracilis, & semitendinosus

place palm over knee

• cross third finger over second finger
• 3rd finger=anterior cruciate ligament
• 2nd finger=posterior cruciate ligament

runs from anterior tibia to posterior femur

• prevents anterior tibial displacement
• tight during extension

runs from posterior tibia to anterior femur

• prevents posterior tibial displacement
• tight duriung flexion

• medial collateral=tibial collateral
• attaches to medial meniscus
• may see associated injuries

• medial stability
• prevent excess motion from blow to lateral side

lateral collateral=fibular collateral

strong, seldom injured

• lateral stability
• prevent excess motion from blow to medial side

purpose-reduce friction

13 located at knee

necessary because of the many tendons having a relatively vertical line of pull against bony areas and other tendons

area behind the knee

• contains nerves and blood vessels
• tibial nerve
• common peroneal nerve
• popiteal artery and vein

diamond-shaped fossa

• superomedial
• semitendinosus
• semimembranosus
• superolateral
• biceps femoris
• inferior-medial/lateral heads
• gastrocnemius

• anteriorly
• 1-joint
• vastus lateralis,
• medialis,
• intermedialis

• 2-joint
• rectus femoris

Laterally

• 2-joint
• tensor lascia latae

• Posteriorly
• 1-Joint Muscles
• Biceps femoris (short head)
• Popliteus

2-Joint Muscles

• Biceps femoris (long head)
• Semimembranosus
• Semitendinosus
• Sartorius
• Gracilis
• Gastrocnemius

• –Provide stability to the knee
• –Do not have a prime-mover function
• •Size
• •Angle of pull
• •Tensor fascia latae
• –Contributes to lateral stability
• •Gracilis and sartorius
• –Contribute to medial stability
• •Gastrocnemius and hamstrings
• –Medial and lateral stability
• •Quadriceps
• –Anterior stabilizer

position in which the distal segment is located toward the midline

position in which the distal segment is situated away from the midline