The Knee Joint - Bones, Joints, Muscles

Question 1

There are 3 likely knee conditions that can occur from the strange articulations of the knee.
Genu Varum
Genu Valgum
Genu Recuratum
What happens to the femur with each condition?

Answer 1

Genu Varum (Bow legs) - Knees naturally outwards, femur rotated externally
Genu Valgum (Knock-Knees) - Knee collapse inwardly, femur rotated internally 
Genu Recuratum (False Curvature) - Femur rotated internally, tibia rotated internally

Question 2

What are the characteristics of FEMORAL medial and lateral condyles?

Answer 2

Medial Femoral Condyle:
- Rounded in profile 
- Extends more distally (Longer)
- Narrower
Lateral Femoral Condyle: 
- Flattened in profile 
- Shorter distally (Shorter)
- Wider surface

Question 3

What are the characteristics of the medial and lateral TIBIAL condyles?

Answer 3

Medial Tibial Condyle: 
- Larger surface area 
- Oval in shape 
- Concave in all axes 
Lateral Tibial Condyle: 
- Smaller surface area 
- Rounded in shape 
- Concave in medial/lateral axis

Question 4

How does the femur move on a fixed tibia?

Flexion

Answer 4

Posterior roll –> Anterior glide –> Lateral spin to unlock knee (The opposite in extension)

Question 5

How does the tibia move on a fixed femur?

Flexion

Answer 5

Posterior roll –> Posterior glide –> Medial spin to unlock knee (The opposite in extension)

Question 6

What are the functions of the medial and lateral menisci of the knee? What are the similarities and differences?

Answer 6

Similarities - Both menisci have an anterior and posterior horns (Most of the weight bearing), have attachment points for the transverse ligament on the anterior of the tibia.
Differences - The medial meniscus is attached to knee capsule for weight bearing (More prone to injury due to this), lateral is unattached and allows more movement.

Question 7

What is unique about the ligaments of the knee?

Answer 7

They are intracapsular and extra-synovial, to prevent the ligament being excessively damaged.

Question 8

What are attachments of the anterior and posterior cruciate ligaments? (ACL and PCL)

Answer 8

ACL - Originates on the anterior condylar area of the the tibia and moves superiorly and laterally to the lateral side for the intercondylar notch.
PCL - Originates on the posterior condylar area of the intercondylar notch and rises superiorly, anteriorly and medially to the medial side of the intercondylar notch

Question 9

What is the intercondylar notch?

Answer 9

It is the area between the medial and lateral condyles of the tibia

Question 10

What are the three bursas (folds of synovial fluid) in the knee joint?

Answer 10

• Suprapatellar
• Prepatellar
• Infrapatellar

Question 11

What happens with the synovial membrane in extension of the knee?

Answer 11

• Due to the posterior of the knee being compressed, the fluid flows to the front of the knee towards to the patellar bursas.
• To give the synovial more surface area to move into, there’s a small muscle which pulls the capsule up the femur to reduce vulnerability of the capsule being damaged.

Question 12

What is the muscle called which pulls the synovial capsule up the femur?

Answer 12

Articularis genus

Question 13

What happens with the synovial membrane in flexion of the knee?

Answer 13

• Due to the the anterior part of the knee being compressed, the synovial fluid flows to the posterior to an area behind the femoral condyles called the popliteal bursa.

Question 14

What 3 anterior aspects of the knee joint protects the joint capsule from being damaged?

Answer 14

• The quadricep complex allows synovial fluid movements; looser capsule.
• Patella bone and patellar tendon
• Lateral and medial retinaculum (contracts with quadriceps)

Question 15

What is the function of the collateral ligaments?

Answer 15

The medial (thick) and lateral (thinner) collateral ligaments protect joint capsule as well as holding the joint together; prevents lateral gliding.

Question 16

What are the insertions of the collateral ligaments?

Answer 16

Medial Collateral ligament:
- Originates on the medial condyle, travels distally to insert in the tibial tubercle.
Lateral Collateral ligament:
- Originates on the lateral condyle, travelling posteriorly and distally to insert to the head of the fibula.

Question 17

What is the function of the popliteus muscle within the knee joint, and what are its insertions?

Answer 17

• The function of the popliteus muscle is to laterally rotate to the femur on the tibia; to ‘unlock’ the knee to allow flexion.
• It originates on the anterior aspect on the lateral femoral condyle on a tendon and passes posteriorly through the joint capsule and inserts to the posterior aspect of the tibia.

Question 18

What are the posterior ‘ligaments’? (They’re more thickenings of the posterior aspect of the joint capsule)

Answer 18

Oblique popliteal ligament: Originates on the medial condyle of the tibia, and moves superiorly and laterally to insert, roughly, at the intercondylar line of the femur.

Arcuate popliteal ligament: Originates on the lateral condyle of the tibia, sweeps round the popliteus and inserts, roughly, at the intercondylar line of the femur.

Question 19

What are the bony landmarks of the patella?

Answer 19

Anteriorly: 
- Base; most proximal and superior
- Apex; most distal and where patella ligament arises
Posteriorly: 
- Lateral facet; larger in surface area
- Medial facet; smaller in surface area
(Covered in hyaline cartilage)

Question 20

What happens to the patella during flexion and extension?

Answer 20

Extension: The patella rises as far anteriorly as possible; slightly more anterior than its attachment to the tibial tuberosity.

Flexion: The patella is dragged to the inferior side of the femoral condyles.

Question 21

What is the fibrous tissue connecting the tibia and fibula together?

Answer 21

Interosseous membrane

Question 22

There are two tibiofibular joints, what type of joints are they and what are their functions?

Answer 22

• Proximal Tibiofibular joint is a plane (gliding joint) synovial joint and will glide superiorly and laterally.
• Distal Tibiofibular joint is a fibrous joint, specifically called Syndesmosis, which are two bones running parallel connected my the interosseous membrane; creates very limited movement.

Question 23

What are the 5 significant quadricep muscles from most superficial to the deepest?

Answer 23

• Sartorius
• Rectus Femoris
• Vastus Lateralis
• Vastus Medialis
• Vastus Intermedius

Question 24

What are the insertions of the vastus muscles?

Answer 24

• The Vastus Lateralis and Medialis both originate from the posterior aspect either side of the intertrochanteric line and distally around the patella to the tibial tuberosity; creating the retinaculum
• The vastus intermedius has a proximal attachment of the anterior shaft of the femur and distally attaches to the base of the patella and over the patella to the tibial tuberosity.

Question 25

What are the insertions of the Sartorius and the Rectus Femoris?

Answer 25

• The Sartorius has a proximal attachment of the ASIS and travels laterally then spirals medially to distally insert to the medial tibial tuberosity
• Rectus Femoris has a proximal attachment of the AIIS and distally attaches to the base of the patella as well as the tibial tuberosity.

Question 26

What movements do the quadriceps create? (All the muscles together/individually/pairs)

Answer 26

Primarily, Extension of the leg at the knee

• Can perform the beginning of hip flexion; sartorius and rectus femoris
• Can perform medial or lateral rotation to return the leg from that opposite movement; pivoting the patella

Question 27

What are the 3 hamstring muscles

Answer 27

• Bicep Femoris
• Semitendinosus
• Semimembranosus

Question 28

What are the insertions of the Bicep Femoris?

Answer 28

Bicep Femoris: Has a proximal attachment on the ischial tuberosity and the linea aspera (long bony landmark of the posterior of the femur) and distally attaches to the head of the fibula.

Question 29

What are the insertions of semimembranosus and semitendinosus?

Answer 29

Semimembranosus: Deep to semitendinosus, has a proximal attachment of the lateral side of the ischial tuberosity and distally inserts to the posterior aspect of the medial tibial condyle.
Semitendinosus: Has a proximal attachment to the medial side of the ischial tuberosity and runs to insert in the medial condyle of the tibia.

Question 30

What are the movements of the hamstring muscles?

Answer 30

• All contracting together creates flexion of the leg at the knee.
• Semimembranosus and semitendinosus contracting causes medial rotation
• Bicep femoris, individually, can support lateral rotation

Question 31

Name the 3 significant adductor muscles from most superficial to deepest
They’re are 5, name them if possible

Answer 31

• Adductor Magnus
• Adductor Brevis
• • Gracilis
• Adductor Longus
• • Pectineus

Question 32

What are the insertions of Adductor Magnus?

Answer 32

Proximal attachment: Ischial tuberosity across the pubic ramus
Distal attachment: Attaches posteriorly along the linea aspera and the supracondylar line to the adductor tubercle (above the medial condyle)

Question 33

What are the insertions of Adductor Brevis?

Answer 33

Proximal attachment: Inferior ramus of the pubis

Distal attachment: Along the linea aspera but shorter and more medial

Question 34

What are the insertions of Adductor Longus?

Answer 34

Proximal attachment: Body of ramus of the pubis

Distal attachment: Middle portion of linea aspera, shorter than magnus, most medial