Lower Limb Biomechanics 1 Flashcards
What are the 3 segment of the lower limb?
Thigh
leg
foot
What are the 3 main joints of the lower limb?
hip
knee
ankle
What are the two main functions of the lower limb joints?
movement
weight bearing
What are the possible movements of the hip joint?
flexion extension adduction abduction internal rotation external rotation circumduction
Describe a synovial joint?
surfaces covered in articular cartilage
enclosed in a fibrous joint capsule forming the synovial capsule
filled with synovial fluid which is secreted by the synovial membrane
What are the two functions of synovial fluid?
reduction in jont friction
nourishes articular cartilage
Why is the hip joint intrinsically stable?
ball and socket joint
surrounded by several, large, strong muscles
In which plane do flexion and extension occur?
sagittal
What is the range of hip flexion and extension?
0-140 flexion
0-20 extension
What is the range of abduction and adduction at the hip?
0-30 abduction
0-25 adduction
Which movements occur in the transverse plane?
external and internal rotation
What is the range of external and internal rotation at the hip?
external 0-90
internal 0-70
Why is less internal and external rotation possible when the hip is extended?
soft tissues in the way
What degree of flexion, extension, adduction and abduction and rotation are required to perform the activities of daily living?
120 degrees of flexion extension
20 degrees adduction/abduction
20 degrees rotation
In walking, in which plane does most movement happen?
sagittal (flexion extension)
When standing in unilateral stance, how much does the hip joint force increase than in bilateral stance?
9 times (0.5x -> 4.5x)
Why is abductor muscle contraction required in unilateral stance?
to maintain the pelvis level
What are two articulations at the knee joint called?
tibiofemoral
patellofemoral
What covers the proximal surface of the tibia?
menisci
What is the function of the menisci?
distribute load
shock absorbers
What is the smooth anterior depression between the femoral condyles called?
the trochlea
What does the trochlea develop into posteriorly?
intercondylar notch
Where do the cruciate ligaments attach?
the intercondylar notch
What kind of bone is the patella?
sesamoid bone
What is the function of the fibula?
anchor for biceps femoris
anchor the LCL
Is the knee joint intrinsically stable?
no
What provides the stability of the knee joint?
mainly form its ligaments
Which ligaments lie outside of the joint capsule?
MCL
LCL
What kind of joint is the knee?
hinge joint
What kind of mechanism is employed in the axis of rotation of the knee joint?
screw-home mechanism
What is a screw-home mechanism?
a spiral motion
the tibia rotates internal on flexion and rotates externally on extension as a result of the medial condyle being 1.7cm longer than the lateral condyle
What path does the centre of rotation follow in the knee joint?
semicircle
What is the range of flexion extension at the knee joint?
a few degrees of extension
140 degrees of flexion
what is the range of adduction/abduction at the knee joint?
maximum of 30 degrees - depends on how much knee flexion
in extension, how much rotation is there at the knee?
none - prevented by interlocking femoral condyles
in flexion how much internal/external rotation is there at the knee?
external - 0-45
internal - 0-30
What ROM is required to perform activities of daily living?
full extension
115 degrees of flexion
10 degrees of rotation
