4. Lower Limb Knee Flashcards
3 bones of the knee joint
- Distal femur
- Proximal tibia
- Patella
Femoropatella joint
• Femoropatella joint – patella and anterior aspect of femur
Distal femur - structure
Lateral and medial epicondyles
Lateral and medial condyles
Intercondylar fossa
Patella surface
Distal femur • Patella surface
of femur –articulates with articular surface of patella
Distal femur- intercondylar fossa
• Intercondylar fossa – between 2 fossa articulate with intercondrial emininets on tibia
Proximal tibia - structures
• Lateral and medial tibial plateau
Tibial tuberosity – large lump of bone at front of tibia
Anterolateral tibial tuberosity (Gerdy)
Proximal tibia
• Lateral and medial tibial plateau
○ Artciulate with condyles of femur superiorly
Between them are intercondylar tuberckes of intercondylar eminence
Proximal tibia - tibial euberosity
• Site of attachment for patella ligament and quadriceps
Proximal tibia - Anterolateral tibial tuberosity (Gerdy)
• Attachment for fascia lata
Patella
Posterior
• Articular surface – articualtes with patells surface of femur (medial and lateral articular surface)
Patella is a sesoimoid bone
= completely encased in tendon
Quadriceps femoris muscle tendon
Quadriceps femoris muscle tendon – comes from surperior aspect covers patella comes put other side is known as patellar ligament and attatches to tubial tuberosity of proximal tibia
5 key points about the knee
- Condyles of distal femur articulate with the plateaus of the proximal tibia
- 2 separate articulations between tibia and femur – medial and lateral femorotibial
- Patellar surface of femur articulates with articular surface of the patella
- Fibular NOT involved in articulation
- Femur epicondyles, tibial tuberosity, tibial intercondylar tubercles – attachment sites for ligaments
3 components of knee stability
- Capsule = weak stability
- Ligaments = main stabilisers
- Muscles = main role is movement secondary role is stability
Without stabilsiers the knee would be unstable due to shape of articualr surfaces
2 layers of knee joint capsule
- Fibrous layer (grey layer)
* Synovial membrane (purple)
Knee joint capsule- fibrous layer
○ Covers exterior portion of the joint
○ Anteriorly it joins patella ligament goes round and posteriorly there is a gap for popliteaus tendon to insert
Knee joint capsule- synovial membrane
○ Inner membrane
○ Dips in middle between articular surfaces to give 2 articular cavities (relevant in knee surgery
Knee joint capsule- between fibrous and synovial layers
sites of attachment for cruciates ligaments – between fibrous and synovial layers
Extra capsular knee ligaments
o Collateral ligaments
o Patellar ligaments
o Oblique & arcuate popliteal ligaments
Intra-capsular knee ligaments
o Cruciate ligaments
o Menisci
Extra-capsular ligaments - lateral aspect
• Fibular collateral ligament
○ Runs from Lateral epicondyle of femur to head of the fibular (attaches to fibular)
○ AKA lateral collateral
• Arcuate popliteal ligament
Extra capsular ligament – medial aspect
Tibial collateral ligament
• Medial epicondyle of femur down to tibia
• 3rd point of attachment to medial meniscus
• Weaker than fibular collateral ligament
Medial patellofemoral ligament
• Medial epichondyle of femur to patella
• Hold aptella in place
Extra capsular ligament – posterior aspect
Oblique popliteal ligament
Arcuate popliteal ligament
Both prevent hyperextension of knee
Collateral ligaments
- Fibular collateral ligament
- tibial collateral ligament
Intra- capsular ligaments – cruciate ligaments (posterior view)
Anterior cruciate ligament (ACL)
• Attatches to anterior aspect of the tibia and runs posteriorly
• Weaker
Posterior cruciate ligament
• Attatches to posterior aspect of tibia runs forwards
* They cross over as cruciate means cross * Prevent anterior and posterior rolling of femur
Cruciate ligaments
Anterior cruciate ligament (ACL)
Attatches to anterior aspect of the tibia and runs anteriorly
Posterior cruciate ligament
• Attatches to posterior aspect of tibia runs forwards
Menisci
Medial meniscus
Lateral meniscus
Transverse genicular ligament joins medial to lateral meniscus and stabilises it
Main role = shock absorption prevent large movements
Medial meniscus
- Larger
- 3 attachment points
- C shaped
- Less mobile – attaches to tibial collateral ligament
Damage to tibial collateral ligament affects medial meniscus and vice versa
Laterall meniscus
- 2 attachment points
- Smaller
- Circular shaped
- Freely moveable
Anterior muscles of knee
- Quadriceps = 4muscles
- Join together ine 1 tendon to give quadriceps tendon, passes over patella becomes patella ligament and attached to tuberal tuberoisty
All muscles extend knee
Quadriceps
○ Rectus femoris (most supericifal)
○ Vastus lateralis
○ Vastus medialis
○ Vastus intermedials (deep to rectus femoris)
Posterior muscles of the knee
• Hamstrings (3 muscles) lateral - medial
○ Attach below onto tibia • All muscles flex the knee
Hamstrings
○ Biceps femoris (2 heads)
○ Semi tendonous
○ Semi membranousis
3 medial muscles of the knee
- Gracilis – hip flexor ?
- Sartorius – hip flexor
- Semitendinosus
Also help in knee extension
2 lateral muscles of the knee
• Iliotibial tract – stabilisation
Popliteus
4 Knee movements
Extension
Flexion
Medial rotation
Lateral rotation
Extension of knee
- Anterior aspect knee
* Quadriceps – listed above
Flexion of knee
- Posterior aspect of thigh
* Hamstrings
Medial rotation of knee
- Semitendinosus and semimembranosus (when flexed)
- Popliteus (when extended)
Gracilis and scartorius
Lateral rotation of the knee
- Biceps femoris (when knee flexed)
* More rotation when knee is flexed, less when knee is fully extended
Bursae
—> bursae = fluid filled sac that acts as a lubricant reduces friction between bone, tendon, muscle etc
• Clinically – bursae can become inflammed – suprapatellabursitius
• Some bursae are continuous with synovial cavity of knee – bursts = septic arthritis
Structures in popliteal fossa
Posterior to anterior
Structures
• Tibial nerve (superficial)
• Popliteal vein
• Popliteal artery (deep)
Popliteal fossa borders
- superior Lateral border = biceps femoris
- Superior medial border = semimembranous and semitendonosus and their tendons
- Inferiorly = borders of gastronemious
- Laterally = lateral head of gastronemus
4 compartments of ey
- Anterior
- Lateral
- Deep posterior
- Superficial posterior
3 superior muscles of the leg
Gastronemius
Soleus
Plantaris
Gastronemius
• Gastronemius (most superifical in postrior compartment )
○ Large muscle with 2 heads lateral and medial that join to form calcaneal tendon
○ More prominent in more vigours movement
Plantaris
• Plantaris muscle – small muscle with long thin tendon, minimal movement, used in proprioception and balance in leg
Calcaneal tendon
• Calcaneal tendon (achilies tendon) lateral and medial head of gastronemius and head of soleus muscle join together to form this
4 Deep posterior muscles of leg
- Tibialis posterior muscle – plantar flex foot or ankle
- Flexor hallucis longus (lateral) - flex the big toe
- Flexor digituorum longus (medially) - flex other 4 toes (digits)