L12: Bones, ligaments and joints of leg (incl. knee and ankle) Flashcards
Patella - Knee cap
- largest sesamoid bone of the body
- suspended in the main extensor tendon of the knee
- The deep surface of the patella forms part of the knee joint. [deep surface is smooth, lined with hyaline cartilage, and articulates with patellar surface of distal femur.]
[superficial surface is rough, tendon inserts there]
tibia and fibula
tibia: articulates with: condyles of femur (posteriorly) and talus (inferiorly)
fibula: muscle attachment, and stability of ankle joint
connected by interosseous membrane
tibiofibular joint proximal and distal
Tibia ; articulation
- weight bearing (shin) bone
- second largest bone in body
- Articulation:
- knee joint
- proximal tibiofibular joint
- distal tibiofibular joint
- medial malleolus of ankle joint
Tibia - bony landmarks - proximal
- medial and lateral condyles
- medial and lateral tibial plateau - articular surface
- lateral condyles
- the anteriolateral tibial tubercle (gerdys tubercle) attachment of illiotibial and fascia of lateral thigh
- fibular articular facet on lateral condyle
- Intercondylar eminence
- medial and lateral intercondylar tubercles - fit into intercondylar fossa between femoral condyles
- intercondylar areas (anterior and posterior
- attachment sites for menisci and knee ligaments
Tibia - bony landmarks - anterior
- shaft of tibia: triangular cross-section
- surfaces: medial, lateral/interosseous, posterior
- Shin: anterior border of medial surface
- tibial tuberosity: distal attachment for patellar ligament
- interosseous border: attachment of interosseous membrane
- fibular notch: fibrous attachment at distal tibiofibular joint
Tibia - bony landmarks - posterior
- soleal (popliteal) line: diagonal ridge runs inferomedially to the medial border, for soleus tendon
- nutrient foramen: main artery supplying proximal end of bone and marrow
- medial malleoulus: extends inferior to shaft
- lateral surface of medial malleolus and inferior shaft articulate with talus
Fibula
- slender non-weight bearing bone
- the fibuLA is LAteral to the tibia
- site for muscle attachment
- 1 muscle insertion
- 8 muscle origin
- Articulation:
-Proximal tibiofibular joint
*Distal tibiofibular joint
*Forms lateral malleolus of the ankle
*Does NOT articulate with femur at knee joint
Fibula - bony landmarks - Proximal
-Enlarged head superior to small neck
-Common fibular nerve wraps around neck
-Head has pointed apexand articulates with fibular facet on lateral tibial condyle
Fibula - bony landmarks - distal
- Enlarged
- Lateral elongation to form lateral malleolus of ankle joint
Fibula - bony landmark - shaft
*Twisted and marked by sites of muscle attachment
*Triangular cross section
*Borders: anterior, interosseous, posterior
*Surfaces: medial, posterior, lateral
Palpable landmarks of tibia and fibula - surface anatomy
- Palpable landmarks
- Tibial tuberosity
- Anteromedial surface of the tibia
- Tibial condyles
- Head of fibula
- Neck of fibula (note common fibular nerve passing)
- Medial malleolus
- Lateral malleolus
Tibiofibular joints
Proximal tibiofibular joint
Distal tibiofibular joint
interosseous membrane
joins shafts of tibia and fibula
Oblique fibre direction of ligaments and membrane
- fibres extend inferolaterally from tibia toward fibula
- allow upward movement of fibula during dorsiflexion when wide end of trochlea of the talus is wedged between the malleoli
- resist downward pull due to 8 muscle origins
Proximal tibiofibular joint; articulation
Plane synovial joint
articulation: head of fibula and fibular articular facet on lateral condyle of tibia
Proximal tibiofibular joint; ligaments + movement
- anterior and posterior ligaments of the fibular head
Movement:
slight movement during dorsiflexion of foot due to wedging of trochlea of the talus between the malleoli
Proximal tibiofibular joint; blood supply + innervation
Blood supply: inferior lateral genicular and anterior tibial recurrent arteries
Innervation: common fibular nerve and nerve to the popliteus
distal tibiofibular syndesmosis; articulation
articulation: distal medial surface of fibula and fibular notch of tibia
distal tibiofibular syndesmosis; fibrous joint
Fibrous joint (syndesmosis):
*Interosseous tibiofibular ligament (continuation of interosseous membrane)
*Anterior tibiofibular ligament
*Posterior tibiofibular ligament (inferior transverse tibiofibular ligament)
distal tibiofibular syndesmosis; ankle joint stabiliser
-Keeps lateral malleolus firmly against lateral surface of the talus
*Inferior transverse ligament forms posterior wall of the malleolar mortise for the trochlea of the talus
distal tibiofibular syndesmosis; movement
movement: slight upward movement during dorsiflexion
distal tibiofibular joint (tibiofibular syndesmosis); blood supply + innervation
Blood supply: perforating branch of fibular artery, and medial malleolar branches of anterior and posterior tibial arteries.
Innervation: deep fibular, tibial and saphenous nerves
Knee joint; consists of?
- hinge type synovial joint
> flexion, extension
> also gliding, rolling, and rotation - 3 joints in a single cavity
> lateral tibiofemoral joint
> medial tibiofemoral joint
> intermediate patellofemoral joint - fibula is not involved
tibiofemoral joint
- medial and lateral condyles of femur articulate with medial and lateral condyles of tibia
- non-articular area between condyles
- weight bearing joint of the knee
patellofemoral joint
- facets of the patella articulate with the patellar groove on anterior surface of femur
- allows the pull of the tendon of quadriceps femoris (the main extensor) to be directed anteriorly over knee without tendon wear and increased leverage
joint capsule of knee; borders
- external fibrous layer
- Borders:
> superiorly: proximal to articular margins of femoral condyles
> posteriorly enclosed condyles and intercondylar fossa
> opening posterior to the lateral tibial condyle for popliteus tendon
> inferiorly: margin of tibial plateau - internal synovial membrane
- excludes cruciate ligaments and the infrapatellar fat pad from articular cavity
Extracapsular ligaments of knee joint
- joint capsule: 5 extracapsular (intrinsic) ligaments
> patellar ligament
> fibular collateral ligament
>tibial collateral ligament
>oblique popliteal ligament
>arcuate popliteal ligament
patellar ligament ;
distal part of quadriceps femoris tendon
- from patella to tibial tuberosity
fibular (lateral) collateral ligament
lateral epicondyle of femur to lateral surface of fibular head
tibial (medial) collateral ligament
- medial epicondyle of femur to medial condyle and superior medial surface of tibia
- attached to medial meniscus
oblique popliteal ligament
reinforces capsule posteriorly
acruate popliteal ligament
- strengthens joint capsule posterolaterally
- posterior aspect of femoral head
intra-articular ligaments of knee joint
cruciate ligaments
- criss-cross within joint capsule, but outside synovial cavity
- medial rotation of tibia on femur limited to 10* as ligaments wind around each other
- lateral rotation: unwind, permitting 40* lateral rotation of tibia when knee flexed
- oblique orientation means one ligament or part thereof is always in tension
Anterior cruciate ligament - ACL
attachments + prevents
attachments:
- anterior intercondylar area of tibia
- posterior part of medial side of lateral condyle of femur
limits rolling of femoral condyles on tibial plateau during flexion (converts rolling to spin)
prevents:
- posterior displacement of femur on tibia
- hyperextension of knee
Posterior cruciate ligament - PCL
attachment + prevents
Attachments:
- posterior intercondylar area of tibia
- anterior part of lateral side of medial condyle of femur
Limits rolling of femoral condyles on tibial plateau during extension (converts rolling to spin)
Prevents:
- anterior displacement of femur on tibia
- hyperflexion of knee
Menisci of knee joint
*Medial and lateral menisci
*Crescent shaped fibrocartilage with wedge cross section on articular surface of tibia
*Anchored to intercondylar area of tibia and attached to joint capsule
*Medial meniscus fixed to tibial collateral ligament
*Deepen surface to provide passive joint stabilisation
*Shock absorption
bursa:
a synovial sac found in between parts in a joint to reduce friction
bursae around knee joint
- at least 12 bursa around knee
suprapatellar bursa:
between quadriceps and femur
subcutaneous prepatellar bursa:
between apex of patella and skin
infrapatellar bursa:
deep and superficial (subcutaneous)
- deep between tibia and patellar ligament
- superficial between patellar ligament and skin
semimembranosus burse:
located between semimembranosus and gastrocnemius muscles
neurovascular supply - knee
Blood supply
- 10 vessels form peri-articular genicular anastomoses around knee
- middle genicular branches of popliteal artery penetrate fibrous layer and supply cruciate ligaments, synovial membrane and peripheral margins of menisci
neurovascular supply - knee
innervation
nerves supplying muscles crossing the knee joint also supply the joint
> femoral: anterior aspects
> tibial: posterior aspects
> common fibular: lateral aspects
> saphenous (cutaneous): medial aspect
ankle joint (talocrural articulation)
*Hinge-type synovial joint
*The tibia and fibula are bound together by strong tibiofibular ligaments producing a bracket-shaped socket known as a mortise
*The body of the talus bone fits snugly into the mortise formed by the lateral malleolus (fibula) and medial malleolus (tibia)
*The articulating part of the talus is wedge shaped (wider anteriorly)
lateral collateral ligament
lateral ligament (3 separate ligaments) from lateral malleolus
> anterior talofibular ligament
> posterior talofibular ligament
> calcaneofibular ligament
stabilises ankle during inversion (toes up)
Medial (deltoid) collateral ligament
attachment + role
- proximal attachment to medial malleolus
- distal attachments to:
- talus: anterior and posterior tibiotalar parts
- calcaneus: tibiocalcaneal part
- navicular: tibionavicular part
Stabilises ankle during eversion and prevents subluxation
ankle (talocrural) joint capsule:
-capsule is thin anteriorly and posteriorly
- supported on each side by strong lateral and medial collateral ligaments
Ankle joint capsule
Lateral ligament (3 separate ligaments) from lateral malleolus
- anterior talofibular ligament
- posterior talofibular ligament
- calcaneofibular ligament
stabilises ankle during inversion
ankle joint capsule
Medial (deltoid) ligament
proximal attachment to medial malleolus
distal attachments to :
- talus
- calcaneus
- navicular
Stabilises ankle during eversion and prevents subluxation
Ankle (talocrural) joint - neurovascular supply
blood supply + nerve supply
blood supply: malleolar branches of fibular and anterior and posterior tibial arteries
nerve supply:
- saphenous
- tibial
- sural
- superficial and deep fibular nerves
foot drop
- patient cannot dorsiflex foot
- fracture at right fibular neck
- broken fibula causes damage to peroneal - -nerve
- a brace prevents foot from dropping
knee injury: unhappy triad / terrible triad
lateral side of knee, complete or partial tear of :
- cruciate ligament
- medial collateral ligament
- medial fibrocartilage meniscus
knee injury: dislocation
usually anterior due to hyperextension of knee
damage to popliteal artery
knee injury: patellar dislocation
- slips out of normal position in patellofemoral groove
- direct blow or sudden twist of leg
- quadriceps muscle pulls patella proximally and laterally
anterior cruciate ligament injuries
ACL injuries occur when bones of the leg twist in opposite directions under full body weight
posterior cruciate ligament injuries
PCL occur usually to force
femur moves forward and tears PCL
Knee arthroplasty (replacement)
*Replaces cartilage surface
*Total: distal end of femur, proximal end of tibia, posterior surface of patella
*Femur component – metal
*Tibial component – plastic
*Patella – plastic patellar implant
*Partial or uni-compartmental: only one side replaced
prepatellar bursitis ( housemaid’s knee)
cause: excessive and repeated friction between skin and patella, e.g. jobs associated with kneeling
Inflammation of bursa in front of kneecap
infrapatella bursitis ( clergyman’s knee)
cause: excessive friction between skin and tibial tuberosity, e.g. roofers, tilers who dont wear knee pads
popliteal cyst (bakers cysts)
- fluid filled sacs in synovial membrane in popliteal fossa region
- usually, a complication of chronic knee joint effusion
tibiofibular syndesmosis injury
- high ankle sprain
- injury to distal tibiofibular syndesmosis ligaments
- dorsiflexion and eversion of the ankle with internal rotation of the tibia
- radiography criteria: widening of tibiofibular ‘clear space’ to greater than 6 mm
ankle sprain
- most common major joint injury
- torn fibres or ligaments
- usually, an inversion injury involving twisting of weightbearing plantarflexed foot
- anterior talofibular ligament is most vulnerable
