Lower Extremities

Which ligament provides the primary restraint against anterior translation of the tibia on the femur?

Anterior Cruciate Ligament (ACL)

What articulation forms the patellofemoral joint?

The patella and patella groove of the femur

By creating tension in the iliotibial band, the contraction of which muscles helps to stabilise the lateral aspect of the knee?

gluteus maximus and Tensor Fascia Latae

Which bones make up the rear foot, mid foot and forefoot?

rear foot: talus and calcaneus mid foot: tarsals forefoot: metatarsals and phalanges

What is the Q angle and how is it measured?

The Q angle is the relative offset of the asis vs the hip joint coming down, and is general 10-20 degrees

In most clinical situations the talocrural joint is considered to function as a hinge joint. Therefore, what is the primary action occurring at this point?

Dorsiflexion/plantaflexion

Describe the movement pattern between the articular surfaces of the tibiofemoral joint when the tibia extends in relation to the femur. How about when the femur moves in relation to the tibia?

During extension of the Tibia in relation to the Femur, the tibia rolls and glides anteriorly around the femoral condyles, and the tibia externally rotates. During flexion the opposite occurs. During extension of the Femur in relation to the Tibia, the Femur rolls anteriorly and glides posteriorly over the articular surfaces of the Tibia and internally rotates. the opposite occurs for flexion.

True or False. The component motions make up pronation/supination?

True

True or False. The medial articular surfaces of the tibiofemoral joint have better congruency than the lateral articular surfaces?

True

True or false. The femoral articular surfaces are larger than the tibial articular surfaces? How does this affect the movement between the articulating surfaces?

True

True or false. The medial meniscus is larger than the lateral meniscus but covers a smaller area on the tibial plateau?

True

True or false. The menisci move in association with the movement between articular surfaces of the tibiofemoral joint.

True

True or False. Genu recurvatum can increase the stress of the posterior joint capsule and anterior cruciate ligament?

True.

Rotations in the transverse plane are required during knee flexion/extension. During knee extension the tibia must __________________ in relation to the femur.

External rotation

True or false. The posterior cruciate ligament limits anterior translation of the tibia on the femur?

False

Which ligament is the primary restraint against a varus force acting on the knee?

Lateral Collateral Ligament

Which muscles make up the pes anserinus? How do these muscles work together to dynamically stabilise the knee?

semiembranosis, sartorius and gracilis, and they all work to flex and internally rotate the knee.

Which three (3) muscles provide dynamic stability to the medial aspect of the knee?

1. Gracilis 2. Sartorius 3. Semitendinosus

Why is the subtalar joint critical during walking?

1. It acts to translate the motion of the tibia to the foot or the rotation of the foot to the tibia 2. Its mobility allows the foot to assume positions that are independent of the orientation of the ankle and leg above. This is important for walking on sloped surfaces or when quickly changing directions.

Which two muscles are the primary evertors?

1. Peroneus Longus 2. Peroneus Brevis

What are three purposes of the arches of the foot?

1. Protects the nerves, blood vessels and muscles on the planta surface of the foot from compression during weight bearing. 2. The help to attenuate load during ground contact 3. They help store mechanical energy then release it to improve the efficiency of walking.

What is the key role of the popliteus muscle during flexion of the tibiofemoral joint from a fully extended position?

1. Rotates the tibia internally to initiate tibial on femoral flexion OR for closed chain tasks. 2. Rotates the femur externally to initiate femoral on tibial flexion 3. Dynamic stabiliser: - Reinforces the PCL - Helps to prevent posterior translation of the tibia - Supports the knee medially by controlling external rotation - Its strong tendon helps to resist knee valgus

Which of the two primary planta-flexors is well suited for postural control?

1. Soleus 2. Gastrocnemius

Which two (2) muscles indirectly provide dynamic stability to the lateral aspect of the knee?

1. Tensar Fascia Latae 2. Gluteus Maximus

What are three (3) systems to prevent lateral deviation (lateral tracking) of the patella during knee extension?

1. The lateral femoral condyle extends further anteriorly, acting as a buttress against lateral displacement. 2. Medially directed force of the vastus medialis 3. passive resistance of the medial extensor retinaculum.

What are TWO measures that help to prevent the lateral deviation of the patella?

1. The surface of the lateral femoral condyle extends further anteriorly and acts as a buttress against lateral displacement of the patella/ 2. Medially directed stabilising force from the fires of the Vastus Medialis provide passive resistance to the lateral pull of the patella. 3. The medial extensor retinaculum also provides passive resistance against the lateral pull of the patella.

What are three (3) joints that make up the knee?

1. Tibiofemoral joint 2. Proximal tibiofibular joint 3. patellofemoral joint

What are three (3) possible factors that may account for the screw home mechanism of the knee?

1. To accomodate the larger curved surface of the medial femoral condyle. 2. Slight pull on the quadriceps muscle group 3. Passive tension in the ACL and PCL

The obliquity of the axis of rotation at the subtalar joint creates equal amounts of which two component motions?

1. inversion/eversion 2. adduction/abduction

What are two actions produced by tibialis posterior?

1. plantaflexion 2. inversion

What are the important functions of the foot?

1. support body weight 2. Adapt t uneven surfaces 3. Attenuate ground contact forces 4. acts as a rigid lever during propulsion

What is the screw home mechanism of the knee? What are TWO potential causes?

As the knee moves towards full extension, external rotation of the tibia is required. 1. To accommodate the larger curved surface of the medial femoral condyle. 2. Passive tension in both the ACL and PCL 3. Slight lateral pull of the quadriceps muscle group 4. ITB

Which ligament provides the primary constraint against valgus forces acting on the knee?

Medial collateral ligament

Does pronation of the subtalar joint during the support phase of the gait cycle make the foot more mobile, less mobile or does it have no effect on foot mobility?

Pronation of the ankle/foot complex "unlocks" the transverse tarsal joint and makes the foot more mobile so that it can adapt to the walking surface.

What component motions make up pronation and supination?

Pronation: dorsiflexion, eversion, abduction Supination: plantaflexion, inversion, adduction

Why might a small amount of hyperextension at the knee be beneficial when standing?

Puts knee into close packed position, increasing joint congruency.

What bony feature helps to create the Q angle? How does the Q angle help to create a lateral pull on the patella during knee extension?

The anterior superior iliac spine and the midpoint of the patella.

What causes the tendency for the patella to be displaced laterally during extension of the tibia in relation to the femur?

The decrease in contact area as extension occurs.

Describe the differences in the shape of the articulating surfaces on the medial and lateral femoral condyles.

The lateral condyle is straight extending further anterior than the medial condyle and the medial condyle is smaller and has a curved surface.

Describe how the patella moves during extension of the tibia in relation to the femur?

The patella slides proximally, with its contact area decreasing as the flexion angle decreases..

Primary passive support for the medial longitudinal arch is provided by which structure?

The planta aponeurosis

Whilst the menisci act to improve the congruence between the articular surfaces of the tibiofemoral joint, what is considered to be their primary function?

The primary function of the menisci is to increase the contact area of the articulating surfaces, thereby decreasing the compression stress on the articular cartilage.

What is the primary function of the menisci? Do menisci have the potential for repair if damaged?

To increase contact area between the articular surface and condyles and decrease compressive stress on the articular cartilage.

What is the primary function of the patella?

To increase the length of the moment arm of the quadriceps tendon

What is the primary function of the patella?

To increase the moment arm of the quadriceps tendon.

Adduction/abduction of the ankle/foot occurs in which plane?

Transverse

Why is mobility of the first metatarsal important?

because it as considerable involvement in weight bearing and propulsion during gait

Which two bones form the subtalar joint?

calcaneus and Talus