The Knee Flashcards
The knee joint
- type of joint
- location
- modified hinge joint
- b/w medial/lateral epicondyles of femur and medial/lateral tibeal plateaus
How is the knee most stable?
extended
Patella
- articulates with
- purpose
- patellar articulate surface of femur
- protects tendons from wear and tear
Capsule of the knee joint
-reinforcements
- anteriorly: quadriceps tendon, patellar ligament
- posteriorly: oblique and arcuate ligaments
- medially: tendons of gracilis, sartorius, and semitendonous (pes anserines)
- laterally: iliotibial band
- medial and lateral collateral ligaments
Medial Collateral Ligament (MCL)
- purpose
- location/insertion
- aka tibial
- strengthen knee joint, helps keep it in extended position
- resist valgus force
- epicondyles of femur and tibia
- deep attachment to medial meniscus
Lateral Collateral Ligament (LCL)
- purpose
- location
- aka fibular
- strengthens knee joint, helps keep it extended
- resists varus force
- runs between lateral epicondyle of femur and fibula
Medial and Lateral menisci
- fibrocartilage
- add depth and cushion to tibial plateau, shock absorbers
- facilitate weight transfer from femur to tibia
- medial (thicker posteriorly), lateral (uniform)
Anterior Cruciate Ligament (ACL)
- location
- purpose
- intercondylar area of tibia –> lateral femoral condyle
- stabilize knee internally, maintain extended position, prevent excessive movement b/w femur and tibia
- resists anterior movement of tibia on the femur (posterior movement of femur on tibia)
Posterior Cruciate Ligament
- location
- purpose
- intercondylar area of tibia –> medial femoral condyle
- stabilize knee internally, maintain extended position, prevent excessive movement b/w femur and tibia
- resists posterior movement of tibia on the femur (anterior movement of femur on tibia)
What injury often accompanies injury to MCL?
tearing of medial meniscus (because they are so closely connected
What movement must the knee do in order o completely extend (lock)? Requires what muscle?
- medial rotation of femur on tibia
- politeus
Flexion (knee)
- muscles
- innervation
- hamstrings (biceps femoris, semitendinous, semimembranous) during walking/weight bearing
- gracilis and sartorius
- gastrocnemius (when n-w-b)
- Sciatic Nerve (L4-S3), Obturator (L2-4)
Extension (knee)
- muscles
- innervation
- quadriceps muscles (rectus femoris, vastus lateralis, vastus medialis, vastus intermedius)
- Femoral Nerve (L2-4)
Blood Supply to knee
genicular branches of politeal and femoral arteries
- sup medial genicular artery
- inf medial genicular artery
- inf lateral genicular artery
- sup lateral genicular artery
- descending lateral genicular artery
- recurrent branch of anterior tibial artey
Q angle
- normal
- small
- large
- angle between femur and tibia (femur slightly oblique)
- genu varum: medial weight bearing –> damage menisce/joint cartilage, bow leg
- genu valgum: lateral weight bearing –> knock knees
Genu varus
- small Q angle
- medially directed weight bearing
- damage to menisci and joint cartilage–> osteoarthritis (athrosis)
- excessive stress on LCL
- bow leg
Genu valgus
- large Q angle
- laterally directed weight bearing
- excessive stress on MCL, lateral meniscus, articulate surface of lateral femoral and tibial condyles
- knock knee
What can be caused by twisting or turning knee quickly while foot is firmly planted? Why is it bad? What is the treatment?
- torn menisci, relatively common
- menisci are avascular and don’t heal well
- trim, reshape, or remove