Lecture 5 - The Knee Flashcards
What are the 3 bones that articulate at the knee and what are the joints?
Femur, patella, tibia
Tibiofemoral joint (the knee) - hinge - tibia and femur
Patellofemoral joint - gliding - between femur and patella
What are the knee ligaments?
Anterior Cruciate Ligament
Posterior Cruciate Ligament
Lateral / medial collateral ligament
Lateral / medial menisci
What is the role of the ACL?
The ACL prevents anterior translation
What is the role of the PCL?
The PCL prevents posterior translation
What is the role of the Collateral ligaments?
They reduce side to side movement
What is the role of the menisci?
Stability, lubrication and shock absorption
Medial menisci is connected to the MCL
What is the patella?
Sesamoid bone - embedded in the quadriceps/ patellar tendon
Function - Improve mechanics of the knee - it gives a longer lever arm for the tendons being pulled around the knee - increases the torque
Protects the anterior knee structures from trauma
Outline the anatomy of the pelvis
Ilium
Iliac crest
ASIS, Iliac spine , AIIS
Acetabulum - Where the femur connects to the ilium
Ischium
Ischial tuberosity
Outline the anatomy of the femur
Head of the femur which articulates with the acetabulum
Greater trochanter
Lesser trochanter
Linea Aspera
What are the muscles of the quadriceps?
Rectus femoris - O - AIIS I - Tibial tuberosity
Vastus medialis - O - Medial side of the Linea aspera I - Tibial tuberosity
Vastus Intermedius O - Anterolateral femur I- Tibial tuberosity
Vastus Lateralis - O - Greater trochanter and lateral Linea Aspera I - tibial tuberosity
All carry out knee extension
With the RF being a hip flexor aswell
What are the muscles of the hamstrings?
Biceps femoris - Long head O - Ischial tuberosity Short head O - Linea aspera I -Head of fibula
Semitendinosus - O - Ischial tuberosity I - Anteromedial tibia (pes anserinus) (50% Tendon)
Semimembranosus - O Ischial tuberosity I - Medial condyle of tibia
All carry out knee flexion
Hip extension (except BF short)
BF - external rotation
SM and ST internal rotation
What are all the knee flexors?
Hamstrings
Gastrocnemius
Popliteus - back of the knee - rotation
Sartorius - longest muscle in the body - O ASIS I Anterior medial tibia
Gracilis - O -Ischium I anterior medial tibia
Outline the kinesiology of biarticular muscles
When a muscle with multiple joint actions is activated it attempts to shorten and pull the origin closer to the insertion
SO
Applying equal forces at the O and I generates a torque at both joints and it attempts to perform all of its actions but it is going to move first at the one with the better lever arm
Outline the malalignments of the knee
The Q angle represents the angle of the line of pull of the quadriceps
It is between a line drawn from the ASIS to the midpoint of the patella and another from the midpoint of the patella and the tibial tuberosity
In males 12 -13 degrees
In female 16 -18 degrees due to a wider pelvis
What is the difference between valgus and varus?
Valgus - Genu Valgum is knock knees - high Q angle
Varus - Genu Varum is bow legged - low Q angle
What is Chondromalacia Patella?
Runners knee
Mistracking of the patella and damage to the patello- femoral cartilage
Risk factors
Genu valgum
Pronation
High patella
Weak VM
Outline ACL rupture
70% Are non contact
Result from excessive anterior tibial translation
Cutting or landing movements
Relatively extended knee joint position
Knee valgus
Internal rotation of the tibia
Soon after ground contact
