The Knee Flashcards
What is a condyle?
A rounded knob
What is an epicondyle?
A small projection on a condyle
Which side of the tibia is the fibula?
Fibula is on the lateral side of the tibia
What is a tuberosity?
A large roughened marked bony prominence
Where is the tibial plateau?
It is on the uppermost aspect of the proximal tibia
What bone classification is the patella?
Sesamoid bone
What type of joint is the knee joint?
Synovial -> bones held together by a fibrous capsule and accessory ligament. Has a synovial joint cavity
How many degrees of movement does the knee joint have?
2 (flexion/extension and medial/lateral rotation)
Name the similarities and differences of the femoral articulate surfaces
Lateral condyle us shorter and wider
Medial condyle projects more Italy and lateral condyle projects more anteriorly
They are both covered in articular cartilage
Name the similarities and differences of the tibial articular surfaces
Medial tibial condyle projects further antero-posteriorly to accommodate the medial femoral condyle
Covered in articular cartilage
Flatter peripherally, covered with semi-lunar cartilages (menisci)
What is the function of the patellar>
Improve mechanical efficiency of the quadriceps muscle group by increasing lever arm and increasing angular torque/moment
What is the Q’ angle?
The angle between the quadriceps muscle and the patellar tendon
How do we measure the Q’ angle using bony landmarks?
Measured as angle between line from ASIS to centre patella and line from centre patella to tibial tuberosity
What does Q’ angle represent?
The angle of quadriceps muscle force
What are the normal Q’ angles?
Normal angle is 13° (men) and 18° (women)
What is patella-femoral joint stability dependent on?
Patella position
Lateral femoral buttress wall
Ratio between VMO and VL
Tightness of lateral retinaculum
What type of joint is the superior tibia-fibular joint?
Synovial plane joint
What are the articular surfaces of the superior tibia-fibular joint?
Head of fibula, tibial lateral condyle, capsule attached around joint margins
What ligaments are associated with the superior tibia-fibular joint?
Anterior and posterior ligaments of the fibular head
What movements occur at the superior tibia-fibular joint?
Small rotational movements during ankle dorsiflexion and plantar flexion
What is the shape of the medial meniscus?
C shaped
What is the shape of the lateral meniscus?
O shaped
Which meniscus is less Mobil’s and more easily damaged (due to blending)?
Medial meniscus
Where is the attachment of the medial meniscus’s anterior horn?
Intercondylar area and anterior cruciate ligament
Transverse and coronary ligaments
Where is the attachment of the medial meniscus’s posterior horn?
Posterior horn inserts into the intracondular region in association with PCL
Where is the attachment of the lateral meniscus’s anterior horn?
Anterior interconylar eminence posterior to ACL
Where is the attachment of the lateral meniscus’s posterior horn?
Posterior intercondylar area anterior to posterior horn of medial meniscus
What is the function of the menisci?
Enhances tibio-femoral joint stability by deepening tibial articular surface (gives it more congruence and makes it more stable)
Acts as a shock absorber
Conforms to changing shape of femoral condyle during knee movement
Where does the knee joint capsule attach posteriorly?
Posterior femoral condyle and intercondylar fossa
Posterior tibial condyles
Where does the knee joint capsule attach medically?
Blends with Gastrocenemius and Semimembranosus
Medial articular margins femoral and tibial condyle
Blends with medial collateral ligament
Where does the knee joint capsule attach laterally?
Lateral femur above popliteus
Lateral tibial condyle
Fibula head
Where does the knee joint capsule attach anteriorly?
Patella and retinaculum
Capsule replaced by quadriceps tendon
Where does the anterior cruciate ligament attach?
Starts in anterior intercondylar area of tibia
Runs posteriorly, laterally and superiorly to posterior part of intercondylar area of lateral femoral condyle
Where does the posterior cruciate ligament attach?
Posterior part of intercondylar area of tibia
Runs anteriorly, medically and superiorly to lateral surface of medial femoral condyle
What movement does MCL limit?
Limits valgus movement of the tibia on the femur
What movement does LCL limit?
LCL limits varus movement of the tibia on the femur
What is valgus deformity of the knee?
Distal aspect is going away from the midline
What is varus deformity of the knee?
Distal aspect is going away from he midlin
What is O’Donoghue;s unhappy triad a combination of injury to?
MCL, ACL and medial meniscus
What could an increased Q’ angle lead to?
Lateralisation of the patella
What does the ACL prevent?
Anterior displacement of the tibia on a fixed femur
What does the PCL prevent?
Posterior displacement of the tibia on a fixed femur
Where do LCL and Biceps Femoris attach to?
The apex of the head of the fibula
What is a bursa?
Fluid filled sack that prevents unwanted friction
Name the bursae of the knee
Suprapatellar bursa
Prepatellar bursa
Superficial infrapatellar bursa
Deep infrapatellar bursa
Pes Anserinus bursa
Semimembranosus bursa
What are the names of the accessory movements performed on the patella-femoral joint?
Longitudinal caudal excursion
Medial side glide and lateral side glide
What are the accessory movements of the superior tibio-fibular joint?
AP glide
PA glide
What are the accessory movemnts of the knee joint?
AP glide
PA glide
Medial side glide and lateral side glide
In what position is the knee joint locked?
In a closed pack position/standing in extension
Which muscle initiates ‘unlocking’ mechanism?
Popliteus
What happens anatomically at the knee joint when you go from sitting to standing?
-femoral condyle roll and slide anteriorly over tibial condyle
Femoral condyle glide posteriorly over tibial condyles (stops femoral condyles rolling off tibial condyles)
Shorter lateral femoral condyle movement stops first
Femur medically rotates around fixed lateral condyle to complete the movement
Describe the mechanism of the knee unlocking mechanism
Femur rotates (spins) laterally on tibia
Femoral condyles roll posteriorly on the tibial condyles
Femoral condyles glide anteriorly on the tibial condyles (this stops femoral condyles from rolling off the tibial condyles)
Name the 4 quadriceps muscles
Rectus Femoris
Vastus Medialis
Vastus Intermedius
Vastus Lateralis
Where does the long head of the Rectus femoris originate?
Anterior inferior iliac spine
Where does the short head of Rectus Femoris originate from?
Rough area of ilium superior to acetabulum
Where does Rectus Femoris insert?
The 2 heads join quadriceps femoris tendon which inserts into base of patella
What are the actions of the Rectus Femoris?
Extends knee and flexes hip
What is the nerve supply of Rectus Femoris?
Femoral nerve L2,3,4
Where is Vastus Intermedius in comparison to Rectus Femoris?
It is deep to Rectus Femoris
Where is the origin of Vastus Intermedius?
Femur-upper 2/3rds anterior and lateral surfaces
Where does Vastus Intermedius insert?
Quadriceps tendon (deep part) and lateral border of patella
Where is the origin of Vastus Medialis?
Femur medial part of inter-trachanteric line, pectineal line, medial lip of linea aspera, medial supracondylar line
Where does Vastus Medialis insert?
Quadriceps tendon and medial border of patella
Where is the origin of Vastus lateralis?
lateral part of intertrochanteric line, lateral margin of greater trochanter, lateral margin gluteal tuberosity, lateral lip linea aspera
Where does Vastus Lateralis insert?
Quadriceps tendon and lateral margin of patella
What are the actions of the Vasti muscles?
Extend knee joint
What is the nerve supply of the Vasti muscles?
Femoral L2, 3, 4
Name the 3 hamstring muscles
Biceps Femoris
Semitendinosus
Semimembranosus
Where is the origin of the long head of Biceps Femoris?
Inferomedial part of upper area Ischial tuberosity
Where is the origin of the short head of Biceps Femoris?
Lateral lip linea aspera (lateral supracondylar ridge)
Where does Biceps femoris insert?
Head of fibula
What action does Biceps Femoris cause at the knee?
Flexion and external rotation
What is the nerve supply of Biceps Femoris?
Sciatic nerve L5-S2
Where is the origin of Semitendinosus?
Inferomedial part of upper area Ischial tuberosity
Where does Semitendinosus insert?
Medial surface of proximal tibia
What action at the knee does Semitendinosus cause?
Flexion and internal rotation
What is the nerve supply of Semitendinosus?
Sciatic nerve L5-S2
Where is Semimembranosus in comparison to Semitendinosus?
Deep to Semitendinosus
Where is the origin of Semimembranosus?
Superolateral impression Ischial tuberosity
Where action at the knee does Semimbranosus cause?
Flexion and internal rotation
What is the nerve supply of Semimembranosus?
Sciatic nerve
What is the action of the hamstrings?
Extend the hip and flex the knee joint
Where is the origin of Sartorius?
Anterior superior iliac spine
Where does Sartorius insert?
Anterior surface of tibia just Inferomedial to tibial tuberosity
What actions does Sartorius cause at the knee?
medial rotation and flexion
What is the nerve supply of Sartorius?
femoral nerve L2,3
Where is the origin of Gracilis?
External surface body of pubis, inferior pubic ramus and ramus of ischium
Where does Gracilis insert?
Medial surface proximal shaft of tibia
What are the actions of Gracilis?
medial rotation and flexion of the knee
What is the nerve supply of Gracilis?
Obturator nerve L3, 4
Which muscle gives the contour of the calf?
Gastrocnemius
Where does Gastrocnemius originate?
Medial and lateral femoral condyles (2 heads -> medial and lateral)
Where does Gastrocnemius insert?
Achilles’ tendon into posterior-superior calcaneus
What are the actions of Gastrocemius?
Knee flexion and ankle plantarflexion
What is the nerve supply of Gastrocnemius?
Tibial nerve S1,2
What is Plantaris deep to?
Gastrocnemius
Where is the origin of Plantaris?
Lateral supracondylar line above lateral head of Gastrocnemius
Where does Plantaris insert?
Medial border of TA and posterior surface of calcaneus
What is the action of Plantaris?
Weak knee flexor and plantar flexor of foot
What is the nerve supply of Plantaris?
Tibial L4, 5, S1
Where does Popliteus originate?
Lateral femoral condyle
Where does Popliteus insert?
Proxmial surface of posterior tibia
Where does Popliteus insert?
Proximal surface of posterior tibia
What is the action of Popliteus?
Unlocks the knee by laterally rotating the femur on fixed tibia
Has a weaker role in flexing knee and medially rotating the tibia
What is the nerve supply of Popliteus?
Tibial nerve L4,5, S1
What does TFL stand for?
Tensor Fasciae Latae?
Where is the origin of TFL?
ASIS (and outer iliac crest to iliac tubercle)
Where does TFL insert?
Anterior surface of tibia just inferolateral to tibial tuberosity (Gerdy’s tubercle)
What are the actions of TFL at the knee?
Stabilises the knee laterally (doesn’t produce any physiological movement)
What is the nerve supply of TFL?
Femoral nerve L2, 3, 4
What does ITB stand for?
IlioTibial Band
What actions/movements can be done at the knee?
Flexion/extension
Internal rotation/external rotation
What are the lateral borders of the Popliteal Fossa?
Biceps Femoris and lateral head of Gastrocnemius
What are the medial borders of Popliteal fossa?
Semimembranosus
Semitendinosus
Medial head of Gastrocnemius
What are the contents of the popliteal fossa?
Popliteal artery and vein
Common perineal and tibial nerve
Lymph nodes and fat
Name the 4 knee flexors
Hamstrings -> biceps femoris, Semitendinosus and Semimembranosus
Sartorius
Popliteus
Gastrocnemius
Name the knee extensors
Quadriceps -> Rectus Femoris, Vastus Intermedius, Vastus lateralis, Vastus Medialis
Name the 4 medial rotators of the tibia on the femur
Semitendinosus
Semimembranosus
Sartorius
Popliteus
Name the lateral rotator of the tibia on the femur
Biceps Femoris
In what position should you palpitate the knee?
Open-packed position
