The knee Flashcards
What are the 3 articulations in the knee joint?
- lateral femoral and tibial condyles with corresponding meniscus 2. medial femoral and tibial condyles with corresponding meniscus 3. patella and femur
What type of joint is the knee joint? What is its action?
Hinge joint Extension and flextion
What is the stability of the knee joint dependant on?
- Strength and actions of surrounding muscles and their tendons 2. The ligaments that connect the femur and tibia
Position of tibia and femur within the thigh and leg?
The femur is positioned diagonally within the thigh The tibia is almost vertical
What is the Q line and Q angle? What is it in men and women?
Line drawn from ASIS to central patella Central patella to ischeal tuberosity Males approx 14o (+/- 3) Females approx 17o (+/- 3)
What happens when the Q angle increases?
- Genu valgum
- Patella subluxation (dislocation)
Why are women at greater risk of pain and injury?
- Pelvis wider so hip joints further lateral
- Femurs have to angle more to medial side to carry body weight
- Medial side of knee carrying more weight
Name the articular ligaments in the knee. What is there function?
- medial and lateral collateral ligaments (tibial and fibular collateral ligament)
- anterior and posterior cruciate ligaments
- patella ligament (patella tendon)
- articular capsule
Stabilise the knee
Describe features of Medial collateral ligament
- Broad flat ligament
- Thickening of joint capsule, attached to medial meniscus.
- Taut in knee extension - prevents knee abduction
Which ligament prevents knee abduction
Medial collateral ligament (tibial)
Describe features of the Lateral collateral ligament (fibular)
- Strong fibrous cord.
- Not attached to joint capsule or lateral meniscus.
- Taut in knee extension -prevents knee adduction
Which ligament prevents knee adduction
Lateral collateral ligament (fibular)
Describe the features of the anterior cruciate ligaments?
- Stops tibia moving forward on femur
- Stabilise knee in extension and prevents hyperextension and excessive internal rotation
Describe the features of Posterior cruciate ligament
- Stops tibia moving backward on femur.
- Stronger the ACL
- Helps stabilise knee especially in flexion
- Also prevents tibia twisting outward (external rotation)
What is the menisci?
•crescent shaped fibrocartilage disks between femoral and tibial condyles.
Explain the morphology of the menisci? Outer and inner edge
- Outer edge of menisci thick and attach to joint capsule.
- Inside edge thin and essentially unattached.
Which menisci is more commonly injured
•Medial meniscus more commonly injured than lateral.
What is the Medial meniscus attached to?
medial collateral ligament and anterior cruciate ligament
Name all the bursa in the knee
Suprapateller bursa
Superficial prepateller bursa
Deep infrapateller bursa
Superficial infrapateller bursa
What are most bursas an extensions of? What are the bursas full of?
•extensions of the knee synovial cavity and are filled with synovial fluid.
What is the functon of the bursa?
Act as cushions against friction and rubbing of the tendons, ligaments and bones around the knee joint
Name the tendons above and below the patella?
Quadriceps tendon Above
Patellar ligament below
What type of boen is the patella?
The largest sesamoid bone in the body
What does the patella test, assess? What is the spinal root for the test?
Integrity of femoral nerve
Spinal roor L2-L4
Name the bounderies of the popliteal fossa?
Biceps femoris
Semimembranosus and Semitendinosus
Medial and lateral head of gastrocnemius
Describe the blood supply to the knee?
Popliteal artery- posterior
Superior and inferior lateral genicular artery
Superior and inferior medial genicular artery
What passes through the popliteal fossa?
Tibial nerve
Popliteal artery and vein
Common peroneal nerve
sural nerve
Label this Xray
Which muscles are responsible for knee flextion? Which nerve innervates them?
•hamstrings (3 muscles at the back of the thigh)
Semimembranosus
Semitendinosus
Biceps femoris
•Innervated by sciatic nerve (tibial part)
What effect does the politeus muscle have on the knee? Which nerve innovates this muscle?
- Weakly flexes knee
- Innervation tibial nerve
- Rotation
- Unlocks knee by rotating femur 5o laterally on fixed tibia
- When foot off the ground and knee flexed, rotates tibia medially
Which muscles are responsible for knee extension?
- Quadriceps (4 muscles at the front of the thigh)
- Innervated by femoral nerve
- Quadriceps femoris = rectus femoris, vastus lateralis, vastus medialis, vastus intermedialis
Which side of the knee carries the most body weight and why?
The medial side of the knee
Because the femure angles medially to carry body weight
