Knee joint Flashcards
muscles flexing the knee joint?
- hamstrings
- gastrocnemius
- gracilis
- sartorius
- popliteus
functional activity of the hamstrings at the knee joint?
- when moving side ways in a seat rotation of the knee comes when feet are firmly on the ground
- the feet are fixed and the body weight is taken onto them; however, the person stays in a sitting position, just allowing the buttock to come clear of the seat
- the trunk is then moved to one side by swivelling of the femur on the upper surface of the tibia
- this is achieved by a combined action of the medial rotators of one knee and the lateral rotators of another
- finally the simultaneous action of the hamstrings on both the hip and knee joints must be considered
- can arise for athletes accelerating towards a bend
- going round a bend they move the trunk upwards into a more upright position as well as to flex the knee of the leg that is being swung- through ready for the next stride
action of gracilis?
- mainly a flexor of the knee
- can adduct the hip
- can medially rotate the leg of the thigh
functional activity of gracilis?
- swing phase in walking when the knee needs to be flexed
- in horse riding, gracilis is used in all its actions
- when strong flexion is required
action of sartorius?
produces many movements which are combined to produces cross- legged sitting i.e. flexion of the hip, knee, lateral rotation of the tibia on the femur
functional activity of sartorius?
- helps to produce any activity which involves flexion of the knee and hip together, combined with lateral rotation of the thigh e.g. breast stroke in swimming
muscles extending the knee joint?
- QUADRATUS FEMORIS
- rectus femoris
- vastus lateralis
- vastus medialis
- vastus intermedius
- tensor fascia lata
action of all quadriceps?
- rectus femoris also flexes the thigh and hip flexor
- main extensor of knee
- vastus medialis is more active in the final stage of extension
functional activity of quadriceps?
- stepping activities
- stair climb and squats
- rectus femoris will mainly form its function in the swing phase of walking when the lower limb is being carried forward and the knee is being extended
- vastus medialis is in the final stages of the knee, helps in the locking mechanism of the joint when the femur is allowed to rotate medially
- standing position= no activity
- when standing on one leg, all the muscles around one knee work statically to provide stability at the joint
action of tensor fascia lata?
- flexion, abduction and medial rotation of the hip joint
- also straightens out the backward pull of gluteus maximus on the iliotibial tract
- tightens the iliotibial tarct with gluteus maximus
- extends the knee
functional activity of tensor fascia lata?
‘toe-off phase’ of walking
links pelvis with tibia together with gluteus maximus
strong medial rotation of hip in extension of the lower limb, pelvis and trunk are prepared to take the thrust relayed through the lower limb by the calf muscles during toe-off phase
muscles laterally rotating the tibia of the knee joint?
biceps femoris
muscles medially rotating the tibia of the knee joint?
Semitendinous semimembranosus gracilis sartorius popliteus
action of popliteus?
- laterally rotates femur on the tibia when the foot is on the ground, thus releasing the knee from its close packed or locked position allowing it to flex
- by extending a lateral pull on the lateral surface of the lateral condyle of the femur, the condyle is rotated laterally about a vertical axis
- this allows the medial condyle of the femur to glide forward releasing the ligaments and muscles involved
- strong flexion draws the tibia backwards on the femoral condyle and if the foot is off the ground it also aids the medial hamstrings in medial rotation of the tibia
- pulls the lateral meniscus backwards during lateral rotation, preventing it from being trapped between the moving bones
