Chapter 10 - The Knee Joint
PE 3320
The Knee Joint
 

Knee joint

largest joint in body
very complex
primarily a hinge joint
 
Bones
Enlarged femoral condyles articulate on enlarged tibial condyles
Medial & lateral tibial condyles (medial & lateral tibial plateaus) - receptacles for femoral condyles
Tibia _ _____________________
___________________________
 
Bones
Fibula - lateral
serves as the attachment for _______________________
does not articulate with __________ or ______________
not part of knee joint
 
Bones
Patella
___________________ (floating) bone
imbedded in ________________ & _______________ tendon
serves similar to a ____________ in improving angle of pull, resulting in greater mechanical advantage in knee extension
 
Bones
Key bony landmarks
Superior & inferior patellar poles
_______________ tuberosity
Gerdy''s tubercle
Medial & lateral femoral ____________
Upper anterior medial tibial surface
______________ of fibula
 
Joints
Ligaments provide static stability
Quadriceps & hamstrings contractions produce dynamic stability
Articular cartilage surfaces on femur & tibia
Menisci form ____________ between bones
attached to ___________________
deepen tibial fossa
enhance stability
 
Joints
Medial meniscus forms _______________ for medial femoral condyle, _____________ meniscus receives lateral femoral condyle
Thicker on outside border & taper down very thin to inside border
Can _________ about slightly, but held in place by various small _____________
Medial meniscus - ____________ & more open _____ appearance
Lateral meniscus - closed ________ configuration, almost like a horse shoe
 
Joints
Either or both menisci may be torn in several different areas from a variety of mechanisms, resulting in varying degrees of problems
Tears often occur due significant ____________ & ____________ forces during ___________ while flexing or extending during quick ____________ ____________ in running
 
Joints
Anterior & posterior cruciate ligaments
____________________________between tibia & femur
vital in respectively maintaining anterior & posterior stability, as well as rotatory stability
 

Anterior cruciate ligament (ACL) injuries

one of ____________________serious injuries to knee
mechanism often involves noncontact ______________forces associated with___________ & _________, ____________, or by violent quadriceps ________________ which pulls tibia forward on femur
 
Joints
Posterior cruciate ligament (PCL) injuries
not _____________ _____________
mechanism of _________ ____________t with an opponent or playing surface
 

Fibular (lateral) collateral ligament (LCL)

_______________ injured
 
Joints
Tibial (medial) collateral ligament (MCL)
maintains ____________ stability by resisting valgus forces or preventing knee from being abducted
injuries occur _________________, particularly in ____________ or ___________ sports
mechanism of teammate or opponent may fall against lateral aspect of knee or leg causing ________ __________ of knee joint & stress to medial ligamentous structures
 
Joints
Synovial cavity
supplies knee with ______________ fluid
lies ____________ patella and between surfaces of tibia & femur
"capsule of the knee"
Infrapatellar _______pad
just _____________to patellar tendon
an insertion point for synovial folds of tissue known as ___________
an anatomical variant that may be irritated or inflamed with injuries or ____________ of the knee
 
Joints
Bursae
more than ________ bursae in & around knee
some are connected to synovial cavity
they __________ ____________ or ___________friction
 
Joints
Extends to 180 degrees (0 degrees of flexion)
Hyperextension of 10 degrees or > not uncommon
Flexion occurs to about 140 degrees
With knee flexed 30 degrees or >
internal rotation 30 degrees occurs
external rotation 45 degrees occurs
 
Movements
________________
bending or decreasing angle between femur & leg, characterized by heel moving toward buttocks
________________
straightening or increasing angle between femur & lower leg
 
Movements
_______________
rotary movement of leg laterally away from midline
_______________
rotary movement of lower leg medially toward midline
Neither will occur unless flexed 20-30 degrees or >
 
Muscles
Quadriceps muscle group
________________ _________
located in anterior compartment of thigh
consists of 4 muscles
___________________
___________________
___________________
___________________
 
Muscles
________ angle
Central line of pull for entire quadriceps runs from ASIS to the center of patella
Line of pull of patella tendon runs from center of __________to center of __________ __________
Angle formed by the intersection of these __________ lines at the patella is the Q angle
Normally, angle will be ______ degrees or less for males & _______ degrees or less in females
Generally, _____________ have higher angles due to a ___________________.
 
Muscles
Q angle
Higher Q angles generally _____________ people in varying degrees to a variety of potential knee _____________ including lateral patellar ____________ or ____________, patellar ______________ syndrome, _______________, and ______________ injuries
 

For people with above normal Q angles, it is particularly important to maintain high levels of ________ & _________in ___________________so as to counteract lateral pull of vastus lateralis

 
Muscles
Hamstring muscle group
responsible for knee ___________________
located in posterior compartment of thigh
consists of 3 muscles
___________________
___________________
___________________
 
Popliteus assist medial hamstrings in knee internal rotation
 
Muscles
Two-joint muscles
most effective when either origin or insertion is stabilized to prevent movement in direction of the contacting muscle
To a degree, muscles are able to exert greater force when lengthened than when shortened
Hamstring muscles & rectus femoris are ___________________ (two-joint) muscles
 
 
Muscles
Knee joint muscles location
Anterior - primarily knee extension
___________________
___________________
___________________
___________________
 
Muscles
Knee joint muscles location
Posterior - primarily knee flexion
___________________
___________________
___________________
___________________
___________________
___________________
___________________
 
Quadriceps Muscles
Strength & endurance is essential for maintenance of patellofemoral stability
often a problem
quads are particularly prone to ___________________ when injuries occur
may be developed by resisted knee extension activities from a seated position
functional weight bearing activities such as step-ups or squats are particularly useful for strengthening & endurance
 
Rectus Femoris Muscle
Flexion of hip
___________________
___________________
___________________
 

Extension of knee

___________________
___________________
 
Hamstring Muscles
Hamstring muscle group
___________________
___________________
___________________
 
Hamstring Muscles
Hamstring muscle ___________________ very common
"Running muscles" function in acceleration
Antagonists to ___________________ muscles at knee
Named for cordlike attachments at knee
All originate on ___________________ tuberosity of pelvis
Semitendinosus inserts on anteromedial ___________________
Semimembranosus inserts on posteromedial___________________
Biceps femoris inserts on lateral ___________________ condyle & head of ___________________
Semitendinosus Muscle
Semimembranosus Muscle
Biceps Femoris Muscle
Popliteus Muscle
 
Knee Extension
Agonists
___________________
___________________
___________________
___________________
 
Knee Flexion
Agonists
___________________ (Long & Short Head)
___________________
___________________
 
Knee Internal Rotation
Agonists
___________________
___________________
___________________
 
Knee External Rotation
Agonists
___________________