0702 - The Knee Flashcards
Describe the knee joint (composition, movements)
Largest synovial joint in the body - modified hinge joint. Composed of 2 condylar joints between femur and tibia, and one saddle joint between femur and patella.
Allows for flexion, extension, and limited rotation in flexion (unimportant).
What movements does the knee allow? What muscles provide it?
Flexion - Hamstrings - semimembranosus and semitendinosus (medial), and biceps femoris (lateral). All originate from ischial tuberosity.
Extension - Quadriceps femoris. Minor role for tensor fascia lata.
What are the 5 components of the extensor mechanism?
Quadriceps, Quadriceps tendon, patella, patellar tendon, tibial tuberosity.
ACL - Origin, Insertion, direction, function
Origin - Intercondylar area, upper surface of tibia (anterior ends of menisci)
Insertion - Postero-medial surface of lateral condyle of femur
Direction - From anterior, distal to posterior proximal - outside synovium but inside capsule.
Function - FFAAT - Fixed Femur Against (prevents) Anterior Translation of Tibia.
PCL - Origin, Insertion, direction, function
From area between posterior ends of the menisci. Passes forwards, medially and upwards to antero-lateral surface of medial condyle of femur. Function - Prevents posterior translation of femur.
Describe the Medial (tibial) collateral ligament
Superficial and capsular.
Superficial - from medial femoral epicondyle to medial tibia just below articular cartilage. Anterior portion distinct, posterior blends into deep posterior capsular ligaments.
Difficult to palpate.
What are the relations of the patella?
Superior - Quadriceps tendon
Inferior - Patellar tendon
Medial - Medial retinaculum, vastus medialis
Lateral - Lateral retinaculum, vastus lateralis, ilio-tibial tract.
Describe the Lateral (femoral) collateral ligament.
Firm, round band running from lateral epicondyle of femour to head of fibula. Popliteus tendon passes beneath it from posterio-inferior to antero-superior to attach to lateral epicondyle of femur.
Injured in varus stress.
Describe the menisci of the knee joint.
Medial and lateral semilunar fibrocartilage on superior aspect of tib/fib respectively. Lateral is smaller but fuller.
Medial is attached to its collateral ligament, lateral is not.
Function - improve congruence of joint surfaces, guide movement, shock absorption.
What are the bursae of the knee joint
Suprapatellar - common site for effusion and cause of Baker’s cyst.
Prepatellar (in front of patellar)
Infrapatellar - superficial and deep to patellar tendon.
What is the blood supply of the knee joint?
The five geniculate branches of the popliteal artery (med/lat sup/inf and middle) anastamose around the knee joint.
What is the innervation of the thigh and knee joint?
Posterior - Sciatic
Anterior - Femoral
Medial - Obturator
What are the four muscles of the quadriceps and their origins?
Rectus femoris - ASIS
Vastus lateralis - proximal intertrochanteric line.
Vastus intermedius - Proximal ⅔ of of body of femur
Vastus medialis - Distal ½ trochanteric line.
All insert to proximal border of patellar, via patellar tendon to tibial tuberosity.
What are the borders of the popliteal fossa?
Above - medial - semimembranosus and semitendinosus ; lateral - biceps femoris
Below - medial and lateral heads of gastrocnemius
Floor - partially plantaris
What are the contents of the popliteal fossa?
Common peroneal nerve
Tibial nerve
Popliteal artery.
