Intro To Biomechsncis

Question 1

Knee function

Answer 1

Largest and most complex joint in the human body.
Mobility- allows flexion, extension, has 3 rotations, 3 translations: 6 degrees of freedom.
Stability: connects femur and tibia, provides musculoskeletal stability.
Load transmission: knee withstands high forces, 3 time ps the body weight during walking.
Knew conserves momentum and reduces oscillations.

Question 2

Knee joint

Answer 2

Enclosed in a joint capsule, contains synovial fluid minimising friction.
Two joints:
Tibiofemoral joint, largest, between tibia and femur.
Patellofemoral joint, between patella and femur.

Question 3

Ligaments

Answer 3

4 ligaments stabilise the femur and tibia together.
Medial collateral ligament and lateral prevent the femur from sliding side to side.
Two crucial ligaments provide anterior/ posterior stability.

Question 4

Menisci

Answer 4

Attached to tibial medial and lateral plateau. Absorb and distribute forces by increasing surface contact area between femur and tibia.
Deepening the medial and lateral tibial plateau, stability to the joint.
Lubrication of joint,

Question 5

Bursae

Answer 5

Supynovial fluid- filled sacs reducing friction between structures and protecting the knee.

Question 6

Knee injuries and osteoarthritis

Answer 6

AnteriorCruciateLigament prevents the tibia from sliding too far forward and provides rotational stability. ACL injuries occur when bones of the leg twist in opposite directions under full body weight.
PosteriorCriciateLigament injury: prevents the shinbone from moving too far backward.
Osteoarthritis: inflammation/ degeneration of the knee joint, bones rub against each other- pain, stiffness, swelling.

Question 7

Knee kinematics

Answer 7

Description of the movement of an object, not accounting for the forces causing the movement.
Study of knee kinematics:
How much a joint can move in three anatomical planes:
Gross measurement
RANGE OF MOTION
Detailed measurements( fluoroscopy a real time moving X-ray images of internal structures). Or photographic, with skin markers, electro goiniometry

Question 8

Surface joint motion

Answer 8

Arthrokinematics: movement between articulating surfaces of a joint (rolling, angular motion, gliding or sliding translatory movement).

Question 9

Rom of tibiofemoral joint

Answer 9

Sagitta plane: flexion/ extension
Frontal plane: abduction (away from body midline), adduction (towards body midline)
Transverse plane: internal/ external rotation.

Question 10

Knee stability

Answer 10

Tibia rotates: outward direction, tightening both cruciate ligaments, locks knee into position.
Tibia is then in position of max stability with respect to the femur, accept load acting through it.