17. Anatomy of the Knee Flashcards
What is the function of the popliteal fossa?
Allows transit of neurovascular structures from the thigh to the leg.
What are the following boundaries of the popliteal fossa:
- Superomedial
- Superolateral
- Inferomedial
- Inferolateral
- Floor
- Roof
Superomedial = Semimebranousus
Superolateral = Biceps femoris
Inferomedial = medial head Gastrocnemius
Inferolateral = lateral head Gastrocnemius
Floor = Popliteus muscle
Roof = Popliteus fascia
What is another name for the common fibular nerve?
Common peroneal nerve
Where does the sciatic nerve commonly bifurcate?
At the superior apex of the popliteal fossa
What is the path of the common fibular nerve?
Wraps around the lateral head of gastrocnemius - then passes deep to muscle in lateral compartment before splitting into superficial and deep branches
What nerve is given off from the common fibular nerve?
The sural nerve (which joints a branch of the tibial nerve)
What is the main cutaneous nerve of the calf?
The sural nerve
What is the content of the popliteal fossa from medial to lateral?
Artery (popliteal artery)
Vein (popliteal vein)
Nerve (tibial nerve)
Which artery is the primary artery to supply blood to the knee and lower leg?
Popliteal artery
Which 5 branches of the popliteal artery are given off around the popliteal fossa?
Superior medial geniculate artery
Superior lateral geniculate artery
Middle geniculate artery
Inferior medial geniculate artery
Inferior lateral geniculate artery
Where is the common fibular nerve found?
The superolateral border of the popliteal fossa
What is the clinical significance of the popliteal fossa?
Pulse point
Can get popliteal aneurysm
Baker’s synovial cyst
Which bones make up the knee joint?
Femur (condyles)
Tibia (condyles and plateau)
Patella (sesamoid bone)
What type of joint is the knee?
Synovial hinge
What type of movement is permitted at the knee joint?
Some rotation, gliding and rolling
Plus flexion and extension (from synovial hinge)
What are the names of the menisci found in the knee?
Medial
Lateral
What is the difference between the medial and lateral menisci of the knee?
Medial = C-shaped & fixed
Lateral = rounded, smaller & mobile
When is the knee joint more stable - extension or flexion?
Extension - because the femur is articulating a flat surface in extension as opposed to a more rounded surface in flexion.
How are the condyles of the femur shaped?
Flat distally and curved posteriorly
What is the benefit of having a knee joint that is more stable in extension than flexion?
The thigh muscles dont have to work as hard during standing - they can relax.
What is the inter-condyle groove for on the anterior surface of the femur?
Articulation with the patella
What are menisci made from?
Fibrocartilage - type 1 collagen, fibroblasts and chondrocytes
What are menisci attached by?
Coronary ligaments
What is the medial meniscus attached to?
The joint capsule & medial/tibial collateral ligament
What is the lateral meniscus attached to?
Popliteal tendon
What are menisci interconnected anteriorly by?
Transverse ligaments of the knee
How many collateral ligaments are there in the knee? What are they called?
2 - Medial (tibial) and lateral (fibular)
How many cruciate ligaments are there in the knee? What are they called?
2 - Anterior and Posterior
What is the function of the cruciate ligaments?
They tighten when the tibia medially rotates on the femur =
Anterior - prevents posterior displacement of femur on tibia AND prevents hyperextension at the knee.
Posterior - prevents anterior displacement and hyeprflexion at the knee
Which is the greater stabiliser of the knee - anterior or posterior cruciate?
Posterior
What is the oblique popliteal ligament an extension of? What is its function?
The semimembranosus tendon
To reinforce the joint capsule
Which ligament is the main soft tissue stabiliser for the patella and prevents lateral displacement?
Medial patellofemoral
Which ligaments of the knee thicken to form the joint capsule?
Medial and lateral patellofemoral
Medial and lateral patellotibial
What do the cruciate ligaments of the knee attach to?
Condyles
What do the collateral ligaments of the knee attach to?
Epicondyles
What is food in the posterior aspect of the distal femur between the condyles?
Intercondyle fossa
What is the action of the arcuate popliteal ligament?
Helps the action of the popliteus muscle (which unlocks the knee)
What does the popliteus tendon pass between?
Joint capsule and lateral meniscus
What does the popliteus tendon insert on?
Lateral femoral condyle
What is the function of the Iliotibial tract?
Stabilises the knee - exerts superior & medial pull on proximal tibia to bring lateral tibial condyle into contact with lateral femoral condyle. Therefore makes sure the condyles are more closely opposed.
Also - extension anteriorly = iliopatella band - which prevents medial displacement of the patella
What are the tendons of the knee joint?
Quadriceps
Pes Anserinus
Popliteus
& Iliotibial Tract
What helps the knee to lock into position?
The congruency and shape of femoral condyles on tibia and menisci
What helps the knee to unlock?
Popliteus muscle
What is the action of the popliteus muscle?
Causes 5 ° of lateral rotation of the femur on tibia
Which muscles are associated with flexion of the knee?
Hamstrings (SM, ST & BF)
Gastrocnemius
Plantaris
Sartorius
Gracilis
Which muscles are associated with extension of the knee?
Quadriceps
How many bursae does the knee have?
12
What categories are the bursae of the knee divided into?
Subcut / superficial
Muscular
Deep infrapatellar / Other
What is bursitis of the subcutaneous infrapatellar bursae known as?
Clergyman’s knee
What is bursitis of the prepatellar bursae known as?
Housemaid’s knee
What are the names of the cutaneous nerves that arise within or pass close to the popliteal fossa?
Sural nerve
Posterior cutaneous nerve of the thigh
What type of bone is the patella?
Sesamoid
What type of joint is the knee joint?
Synovial hinge
What is the name of the ligament that prevents posterior displacement of the femur on the tibia?
Anterior cruciate
What is the movement that occurs in unlocking of the knee joint?
Lateral rotation of the femur on the tibia
What responsible is responsible for the initial lateral rotation of the femur to unlock the knee?
Popliteus
What is the condition called when the bursae of the knee are inflamed?
Bursitis