Week 2 - Knee joint

Question 1

How many articular surfaces does the knee joint have? Describe it/them

Answer 1

Two
The two surfaces are between the femur condyles and the tibial plateaus, with a non-articular surface between the tibial plateaus, directly below the patella

Question 2

Which bones participate in the knee joint?

Answer 2

Tibia and femur

Question 3

Describe possible movement at the knee joint

Answer 3

Uniaxial hinge with a single transverse axis, with slight rotation when semi-flexed

Question 4

Describe the femur condyles

Answer 4

Femoral condyles have a gradually changing curvature, which is sharper on the posterior side
Medial condyle is bigger than the lateral one.
There’s a large notch between the condyles - intercondylar notch, which is in contact with the patella
Articular cartilage across these surfaces is continuous

Question 5

Describe the tibial surfaces involved in the knee joint

Answer 5

Shallow depressions that aren’t really condyles are involved. The medial one is again bigger
The depressions themselves are articulated, but the area between them is not - this is a flat projection

Question 6

Why do we have menisci in the knee joint?

Answer 6

When knee is extended, femoral condyles fit the tibia well
As knee joint is flexed, more of the narrow posterior area comes into contact with tibia, increasing instability
There’s also a much larger space between the bones in this position, which could allow synovial fluid to accumulate in these areas.
The menisci (WFC) on top of the tibial surface, prevents this accumulation and increases stability

Question 7

Describe menisci in the knee

Answer 7

White fibrocartilage
Crescent shaped for each condyle of the femur
Circumferential side is thick, inner margin is thin and avascular
Tips are attached to intercondylar area, periphery blends with the capsule, becoming more fibrous (as opposed to cartilaginous in the inner margins)

Question 8

What is the role of the cruciate ligaments?

Answer 8

Provding anteroposterior stability, by maintaining the attachment between tibia and femur during flexion - prevents ‘rolling off’

Question 9

What are the names of the cruciate ligaments, and how are they named?

Answer 9

Named by attachment to the tibia. If attached anteriorly to the tibia, attach posteriorly to the femur
ACL - anterior cruciate ligament: prevents anterior displacement of tibia
PCL - posterior cruciate ligament
These ligaments cross each other

Question 10

Describe the medial and lateral collateral ligaments

Answer 10

Medial/Tibial - originates at medial femoral epicondyle, inserts on medial surface of the tibia. A broad deep part blends with the capsule of the knee joint
Lateral/Fibular - originates at lateral femoral epicondyle, inserts at head of fibula. Is seperate from the capsule

Question 11

Which ligament moves from the knee meniscus to the femur?

Answer 11

Meniscofemoral ligament

Question 12

Describe the tendon of popliteus muscle

Answer 12

This muscle goes from femur to tibia. The tendon is intra-articular

Question 13

Which surface of the knee completes its movement before the joint is fully extended?

Answer 13

The smaller, lateral anterior surfaces complete their movement first
–> medial surfaces continue to move after lateral surfaces stop

Question 14

When does the femur rotate medially?

Answer 14

At the end of extension - the joint cannot be flexed unless rotated externally

Question 15

Which muscle rotates the knee to unlock extension?

Answer 15

Popliteus

Question 16

What is an advantage of the locked knee position?

Answer 16

Muscle can relax and the iliotibial tract takes over stabilising

Question 17

What forms a bony mortise in the ankle joint?

Answer 17

Tibiofibula syndesmoses

Question 18

What is the bone of the heel?

Answer 18

Calcaneus

Question 19

Which bone is grasped by the mortise?

Answer 19

The Talus

Question 20

Which three bones form the ankle joint? What’s the name of this joint?

Answer 20

Tibia, fibula and talus

This is the talocrural joint

Question 21

In which direction does the top of the foot move in dorsiflexion?

Answer 21

The top of the foot moves up = extension

Question 22

Describe the difference between inversion and eversion of the foot

Answer 22

Inversion - make the soles face each other

Eversion - turn soles away from each other

Question 23

Describe the basic bones of the foot

Answer 23

Tarsal bones: talus & calcaneus
Metatarsals - numbered from medial (big toe) side
Phalanges - same pattern as in the hand

Question 24

Where on the leg would ‘fibular’ or peroneal refer to?

Answer 24

The lateral side of the leg

Question 25

Where on the leg would plantar refer to? What about dorsal?

Answer 25

Plantar refers to the bottom of the foot

Dorsal refers to the top of the foot

Question 26

How would an injured cruciate ligament present?

Answer 26

Would be painful when stretched

Question 27

How would a ruptured cruciate ligament present?

Answer 27

Bone can be moved in the direction not normally allowed by that ligament. Would be relatively unstable

Question 28

What kind of movement would a patient with an injured PCL present with?

Answer 28

Would not put weight on the semi-flexed knee i.e. if descending stairs, would put injured leg first but keep it straight, and reset for every step

Question 29

What are the three compartments of the leg muscles?

Answer 29

Anterior, posterior and lateral

Question 30

What type of muscles are in the anterior compartment of the leg?

Answer 30

Extensors, dorsiflexors of the ankle/toes

Question 31

What type of muscles are in the posterior compartment of the leg?

Answer 31

One small muscle at the top dedicated to the knee. Rest are flexors, and flexors of the ankle/toe. Only one muscle acts on both knee and ankle

Question 32

What type of muscles are in the lateral compartment of the leg

Answer 32

Fibular muscles, evertors of the foot

Question 33

Where do tendons from the posterior compartment enter the ankle?

Answer 33

On the medial side of the ankle

Question 34

Which muscles plantar flex the ankle?

Answer 34

Gastrocnemius (two heads, one from each epicondylar region)

Soleus - flat sheet from tibia and head of fibia

Question 35

What is the triceps surae?

Answer 35

The three headed muscle of the calf

Question 36

Where is the popliteal region?

Answer 36

The back of the knee

Question 37

What is the plantaris?

Answer 37

A tiny muscle with a long tendon that joins the calcaneal tendon

Question 38

Which is the deepest muscle of the leg posterior compartment and what does it do?

Answer 38

This is the tibialis posterior, and it’s an inverter of the foot and a plantar flexor

Question 39

Which muscle in the posterior compartment of the leg is like the profundus of the forearm?

Answer 39

The flexor digitorum longus - it’s a long flexor of the toes, and goes all the way to the distal phalanges

Question 40

What does the flexor hallucis longus do? What about the extensor hallucis longus

Answer 40

Flexor - this is the long flexor of the big toe

Extensor - long extensor of the big toe

Question 41

Which is the most medial muscle of the anterior muscles?

Answer 41

Tibialis anterior, a dorsiflexor of the ankle

Question 42

What’s the name of the long extensor of the toes?

Answer 42

Extensor digitorum longus

Question 43

What is the difference between extensors of the toes vs the fingers?

Answer 43

All toes have a short extensor in the dorsum of the foot

Question 44

What is the fibularis tertius?

Answer 44

A small, inconstant dorsiflexor

Question 45

Describe the two muscles that evert the foot

Answer 45

Both come from fibula
Fibularis longus - crosses sole of foot to the medial side
Fibularis brevis. Sits under longus

Question 46

Which nerve innervates the posterior compartment of the leg?

Answer 46

Tibial nerve

Question 47

Which nerve innervates the anterior compartment of the leg?

Answer 47

The deep fibular nerve, which also supplies the skin of the first web

Question 48

Which nerve innervates the lateral compartment of the leg?

Answer 48

The superficial fibular nerve, which also supplies the skin of the dorsum of the foot