week 5 Flashcards
Convex-concave golden rules
Rule #1: Where the “male” joint surface is moving then roll and glide occur in opposite directions
Rule #2: Where the “female” joint surface is moving then roll and glide occur in the same directions
What is the screw home mechanism?
- SPIN
*The rotation between the tibia and the femur that occurs during terminal knee extension
➢Medial femoral condyle is larger than the lateral femoral condyle
*“Knee locking”
When does it occur
*During extension, the lateral side of the joint completes the motion, resulting in the tibia laterally rotating in the last 20o of knee extension.
*Lateral rotation causes a passive tension in the ACL which creates a fulcrum for lateral rotation and causes it to cross over the PCL and “lock” the knee joint into extension.
How does the patella move?
- Extension: the patella is NOT in contact with the trochlear groove
- 10-20° of knee flexion: the inferior margin of patella articulates with trochlear groove of femur
- As knee flexion increases the contact area of the patella moves proximally
- As knee flexion increases the contact area of the condyles moves posteriorly
Factors contributing to stability at the knee joint
- STATIC(passive):combination of non contractile and bony elements
e.g. menisci, ligaments, capsule, articular cartilage, ITB - DYNAMIC (active): muscles acting on or across the
knee joint
Static: Menisci functions at knee joint
- withstand load bearing forces
2. increase contact area at the tibiofemoral joint → reduces stress at the joint surfaces
3. assist in movement of femoral condyles
4. assist in stabilising translatory movements
what attaches to Medial meniscus
- medial collateral lig
- anterior and posterior cruciate ligs
- semimembranosus
what attaches to Lateral meniscus
- posterior cruciate lig
- medial femoral condyle via meniscofemoral ligs
- popliteus
Movements of the menisci
Considerable distortion throughout range
* Both move posteriorly during flexion (lateral > medial)
* Keeps the menisci under the femoral condyles
*Both active and passive elements contribute to movt.
Static: Ligaments
- Combinations of structures provide stability at the knee – no single structure in isolation
* Concept of primary and secondary restraints
* ✓work together to provide stability
✓primary restraints – ‘workers’
✓secondary restraints – ‘helpers’
* If primary restraint is damaged, the secondary restraint takes the load -> deterioration and increased joint instability
static- anterior tibial displacement 1st & 2nd restraint
primary- ACL
secondary- MCL,ITB
static- posterior tibial displacement 1st & 2nd restraint
primary- PCL
secondary- MCL,LCL, obligue popliteal ligament
static- abductor (valgus) 1st & 2nd restraint
primary- MCL
secondary- ACL, PCL, posterior oblique ligament
static- adduction (varus) 1st & 2nd restraint
primary- not ligamentous
secondary- LCL, posterolateral corner
static-internal tibial rotation 1st & 2nd restraint
primary- MCL, posteromedial corner
secondary- ACL, PCL
static- external tibial rotators 1st & 2nd restraint
primary- posteolateral corner complex
secondary- ACL, PCL
Dynamic: Iliotibial band (ITB)
- Part of the more extensive fascia lata
- Attachments:
- From the fascia surrounding tensor fascia lata and gluteus maximus and medius
- Extends to the anterolateral tibia
- Attachments:
- Crosses both hip and knee
- Has fibrous connections to biceps femoris, vastus lateralis and the lateral patellar retinaculum – may influence patella tracking through these connections
iliotibial band functions
- Affords some lateral joint stability particularly in flexion
Assists ACL in preventing anterior slide of tibia on femur
Quadriceps femoris – function
- Major extensor of knee
- All parts of quadriceps femoris work
throughout the range of knee extension - Stabilises the patella within trochlear groove
- Greatest force needs to be developed at the end of extension range – final 15degs greatest mechanical disadvantage
Vastus medialis – actions and functions
- Vastus medialis – longitudinal fibres (strongly bound to vastus intermedius proximally)
- Knee extensor
- Vastus medialis – oblique fibres
- Weak knee extensor
- Prominent activation in last 40o of knee extension
- Medial patella stabiliser – prevents vastus lateralis from laterally dislocating the patella
- Increases the efficiency of vastus lateralis in knee extension by realigning pull
Tibiofibular joints
- Three joints:
- Superior tibiofibular joint
- synovial, mulitaxial, plane
- Intermediate tibiofibular joint
- fibrous(syndesmosis)
- interosseusmembrane
- long fibres
- Inferior tibiofibular joint
- fibrous(syndesmosis)
- short fibres
Ankle (talocrural) joint Classification and movement
- Classification
- Synovial, uniaxial, hinge
- Movements
- Dorsiflexion 30°
Plantarflexion 50°
Articular surfaces
- Tibia – “female” surface
Inferior (trochlear) surface of the tibia
Medial (tibial) and lateral (fibular) articular facets - Talus - male surface
Tibiotalar surface is weightbearing
Medial and lateral articular facets are non- weightbearing
Articular structures
- Joint capsule
- Attaches to the articular margins of the bones involved
- More extensive anteriorly where it extends onto the neck of the talus
- Collateral ligaments provide medial and lateral reinforcement to the capsule
Medial collateral (deltoid) ligament
extensive, triangular in shape
* superficial parts
- tibionavicular
- tibiocalcaneal
- together prevent
abduction at ankle
* deep parts
- anterior tibiotalar
limit plantarflexion
- posterior tibiotalar
limit dorisflexion
- Lateral collateral ligaments
- Three separate bands
- Anterior talofibular
○ limits plantarflexion
○ preventsposterior slide of tib and fib on talus - Posterior talofibular
○ limits dorsiflexion
○ preventsanterior slide of tib and fib on talus
3) Calcaneofibular
○ limits dorsiflexion
○ preventsadductionat ankle
Movements between tarsals
- Inversion
- plantarflexion
- adduction
- supination
- Eversion
- dorsiflexion
- abduction
- pronation
Subtalar joint & its classification
- Classification:
- Synovial, multiaxial, plane
- Articular surfaces
- facet on under surface of the talus (female)
- posterior facet on upper surface of calcaneus (male)
Subtalar joints - ligaments
- Interosseous (talocalcaneal) ligament
○ two bands both anterior to the joint
○ Run almost vertical lyin the space between talus and calcaneus - calcaneal parts of the ankle ligaments also cross this joint
Talocalcaneonavicular joint (TCN)
- classification: synovial, multiaxial, ball & socket
- articular surfaces
- anterior facet on upper surface of calcaneus (female)
- sometimesintwoparts
- posterior facet of the navicular (female)
- plantar calcaneonavicular (spring) ligament
-head and (partially) neck of the talus (male)
TCN - ligaments
Plantar calcaneonavicular (spring) ligament
bifurcate ligament= medial part only
Calcaneocuboid joint
classification: synovial, multiaxial, plane
* articular surfaces
* facet on anterior surface of calcaneus
* posterior facet of the cuboid
Calcaneocuboid joint - ligaments
- plantar calcaneocuboid (short plantar) ligament
- long plantar ligament
bifurcate ligament (lateral part only)
Tarsometatarsal joint
- classification
- synovial, multiaxial, plane
- movements
- flexion & extension
- some ab & rotation at the first joint
Tarsometatarsal joint
- Articular surfaces
- 1st metatarsal with medial cuneiform
- 2nd (recessed) with intermediate cuneiform, as well as medial & lateral cuneiforms
- 3rd with lateral cuneiform
- 4th with lateral cuneiform & cuboid
5th with cuboid
Tarsometatarsal joints - ligaments
Dorsal & plantar tarsometatarsal ligaments
* limit flexion and extension, respectively
* Cuneometatarsal interosseous ligaments
* 3 slips
* stabilise the tarsometatarsal joint complex
medial part known as Lisfranc ligament
Metatarsophalangeal joints classification and movement
- classification
- synovial, biaxial, condyloid
- movements
- flexion and extension
- abduction and adduction
- articular surfaces
- head of the metatarsal
base of the adjacent phalanx
Metatarsophalangeal joints - ligaments
Collateral ligaments
* limit flexion
* prevent add and abd in flexion
* Plantar ligaments
* forms part of the articular surface
* Limits extension
* deep transverse metatarsal ligaments
* keeps the metatarsal heads together, particularly important in weight bearing
Interphalangeal joints classifications and movements
- classification
- synovial, uniaxial, hinge
- movements
- flexion and extension
- ligaments
- collateral ligaments limit flexion
- plantar ligaments limit extension
where is the interosseous border on tibia
lateral side of shaft next to solar line on tibia
soleal line of tibia
medial part of shaft of tibia
what type of the synovial joint is the ankle
hinge. plantar flexion and dorsiflexion
why is the foot being able to do inversion and eversion so important
allows to adjust to uneven surfaces/ allows efficiency in gait
where is the medial collateral ligament of the ankle
medial side/ triangle in shape
sperfitical parts- tibionavicular & tibiocaneal
deep part- anterior tibiotalar & posterior tibiotalar
where is the lateral collateral ligament of the ankle and what to those
anterior talofibular
posterior talofibular
calcaneofibular
what does the anterior talofibular ligament prevent/ limit
- limits plantarflexion
- preventsposterior slide of tib and fib on talus
what does the posterior talofibular ligament limit/ prevent
- limits dorsiflexion
- preventsanterior slide of tib and fib on talus
what does the calcaneofibular ligament limit/ prevent
- limits dorsiflexion
- preventsadductionat ankle
where is the subtler joint located
between the posterior part of the navicular and the calcareous
where is the talocalcaneonavicular joint located
between the talus/ calcareous and navicular
where is the calcaneocuboid joint located
between posterior calcaneous and posterior cuboid
what movements cause inversion (iPADS)
- plantarflexion
- adduction
- supination
what movements cause eversion
- dorsiflexion
- abduction
- pronation
where is the pet anserine located and does it communicate with the capsule
located between the MCL and the tendons for
sartorius, gracillis and semitendinosis.
This bursa does not
communicate with the synovial capsule of the knee.
where is the suprapatellar bursa located and does it communicate with the capsule
between the quads tendon and superior surface of the patella and the lower anterior femoral shaft.
This bursa communicates with the synovial capsule of the knee.
where is the prepatellar bursa located and does it communicate with the capsule
between the anterior surface of the patella and the skin overlying the knee.
does not communicate with capsule
where is the infrapatellar bursa located and does it communicate with the capsule
deep infrapatellar bursa - between the patella ligament and the anterior superior surface of the tibia.
superficial infrapatellar bursa - between the patella ligament and the overlying skin.
Neither communicates with the synovial capsule.
