Unit 3 Knee Anatomy/Examination Flashcards
What is the largest synovial capsule in the body?
Knee joint capsule
- thin strong fibrous membrane
- capsule has expansions from the ligaments that pass over it
- extensive posteriorly and shorter/thicker on the side
What is the role of the Menisci
- Provide support and stability
- provide depth to the articular surfaces of the tibia so the larger femoral condyles sit with greater stability
Medial Meniscus
- Lunar shaped/ larger and thicker
- sits in the concave medial plateau
- wider in the back than in the front
Lateral Meniscus
- rounder more of an O shape
- sits in the convex lateral tibial plateau
- smaller and thinner
- more mobile
Functions of the Menisci
- reduce the compressive force across the tibiofemoral joint
- stabilize the joint during motion
- lubricate the articular cartilage
- provide support
Patellofemoral Joint Functions
- Provides the articulation with low friction
- protect the distal aspect of the femur from the trauma and the quadriceps from attritional wear
- improve cosmetic appearance of the knee
- improve the moment arm of the quadriceps and increase the extension torque
- Decrease the amount of anteroposterior tibiofemoral shear stress placed on the joint
How does having a patella make the quadriceps stronger ?
- lengthened by the patella which increases the torque
- patella improves the moment arm which is the distance between center of gravity and center of rotation of the quadriceps which increases the extension torque which then allows us to generate more power
- All of this is achieved by elevating the quadriceps from the center of knee rotation
- Patella just acts like a spacer between the patella and the quadriceps –> increasing the efficacy of the quads/ provides it with leverage so we can extend our knee
Anterior Cruciate Ligament
ACL
- Primary restraint for anterior translation of the knee/medial rotation of the tibia on the femur
- Secondary restraint for varus and valgus rotation of the tibia
- Attaches on the anterior intercondylar plateau
Posterior Cruciate Ligament
PCL
- Primary restrain for posterior translation and the medial rotation of the tibia
- secondary restrain to varus and valgus rotation of the tibia
- attaches to the posterior intercondylar plateau
Medial/Tibial Collateral Ligament
- Primary for valgus and lateral rotation of the tibia
- secondary restraint to the anterior and posterior translation of the tibia on the femur
Lateral/Fibular Collateral Ligament
- primary restraint for varus and lateral rotation of the tibia
- Secondary restrain to the anterior and posterior translation of the tibia on the femur
How do the cruciate ligaments receive sensory information?
Nerves:
- genicular
- common branches of the tibia
- peroneal
- obturator
Which is thicker and stronger the ACL or the PCL
PCL is stronger and thicker
- 50% thicker and 2x as strong compared to the ACL
Medial Collateral Ligament
MCL
- extra articular ligament
- Primary stabilizer of the medial side of the knee against valgus force and external rotation of the tibia especially when the knee is flexed
- Anterior fibers are taught in flexion
- Posterior fibers are taught in extension
Oblique Popliteal Ligament
Limits anterolateral rotation
Prevents hyperextension of the knee
Fabellofibular Ligament
- prevents excess internal rotation of the tibia and adds further ligamentous support to the outside of the knee
Fat Pads of the Knee
3 of them: quadriceps, prefemoral, and infrapatellar or Hoffa’s fat pad
- Synovial fluid secretion
- joint stability
- neurovascular supply
- occupiers of dead space
Pain Descriptors Associated with Movement or Trauma:
Locking
Giving way
Pop
Clicking
Crepitus
Tightness
- Locking= meniscal tear/loose bodies
- Giving way= loose bodies, meniscal tears, ligament instability, disuse weakness or neurological, pain
- Pop= at time of injury: ACL tear or osteochondral: fx PCL may or may not report a “pop”
- Clicking= loose bodies, plica, meniscal tears, ITB
- Crepitus= RA/OA
-Tightness= Effusion/contracture
What are some general red flags
- rapid gain or loss of weight
- fever
- night pain unrelated to movement
- insidious pain
- unexplained joint aching
- malaise
What are some tests you can perform for balance?
- berg
- tinetti
- romberg
- DGI
- CTSIB
- TUG
-SLS
Lower Quarter Dermatomes
L1- inguinal line
L2- upper thigh/below inguinal line
L3- Distal thigh above knee
L4- medial malleolus
L5- Dorsum of the foot
S1- lateral border of foot
S2- Achilles tendon
S2-5- saddle area
Lower Quarter Myotomes
L2- hip flexion
L3- knee extension
L4- ankle dorsiflexion
L5- great toe extension
S1- eversion (plantar flexion)
S2- plantar flexion (knee flexion)
S2-S3/5- bladder dysfunction or foot intrinsic muscle wasting
Achilles tendon reflex is what nerves
S1-S2
Patellar tendon reflex nerves
L3-L4
