knee and hip Flashcards
stability
Body ‘designed’ to be efficient
Centre of gravity and soft tissue anatomy “locks”Joints on standing
During walking, combined movements (particularlypelvis) Minimises changes in C.o.G to reduce energyrequired to move
Pathological/biomechanical changes lead toextra/abnormal stresses
musculature/connective tissues
Strength, stability, and movement
Flexion/extension
Abduction/adduction
Rotation
Divided into compartments in leg(ANTERIOR/LATERAL/POSTERIOR) separated bybones and fibrous tissue (fascia)
nervous supply
Motor and sensory nerves arise from thelumbar and sacral regions; L1-S3
Innervate the lower limbs in specific regions (dermatomes/myotomes)
Important in clinical assessment and forconsideration in trauma
the knee description
Largest joint in the body
Bony anatomy relies a lot on soft tissues forstrength/stability
Prone to trauma due to extrinsic position
Injuries Common in teenage/adult life insports/RTC’s
Arthritis / degenerative conditions common
knee joint
Synovial bicondylar joint
Wide range of flexion/extension
Weight-bearing joint
Most force through medial joint
Can be altered by altered gait/pathology:
Genu varus
Genu valgus
the knee on standing
Designed to ‘lock’ on extension
Improves efficiency by reducing muscle fatigue
Enabled by:
Flattened articular surfaces of distal femur
C.o.g anterior to knee, pushes it back
Femur is rotated medially which tightens ligaments
Flexion is initiated by popliteus muscle whichlaterally rotates femur and releases locking
the knee bones
4 bones:
Femur
Tibia
Fibula
Patella
Synovial joint, 2 articulations (3compartments):
Femoro-tibial (medial / lateral)
Patello-femoral
Proximal tibio-fibular join
distal femur
Formed predominantly by two roundedcondyles
Two smaller epicondyles provide attachmentfor collateral ligaments
Condyles separated posteriorly byintercondylar fossa; attachment for cruciateligaments
Anteriorly they form a v-shape for articulationwith the patella
distal femur description
covered by hyaline cartilage
Condyles flattened on distal end
More rounded posteriorly
More stable when extended
patella description
Sesamoid bone in quadriceps femoris tendon
Improves mechanical efficiency by acting as a
Apex inferiorly, flatter superiorly Posterior facets
Prone to medial/lateral dislocation
proximal tibia description
Flattened and enlarged medial and lateral condylesfor weight-bearing and distribution
Separated by raised pair of intercondylar/tibialspines running anterior/posterior
Attachment site for cruciate ligaments/meniscus
Combined to form tibial plateau
proximal tibia
Medial tibial condyle larger and stronger
Slightly concave centrally to articulate with femoralcondyles
Flattened depression on postero-lateral condyle forfibula head
Tibial tuberosity; attachment for patellaligament/tendon
proximal fibula
Not part of knee joint, not weightbearing
Roughly triangular in cross-section
Head enlarged; attachment site Tibio-fibular joint is synovial; minimal movement
OC distal femur
PRIMARY: Diaphysis/shaft (7th week in uTERO)
SECONDARY: distal EPIPHYSIS/FEMORALCONDYLES (~40th week in utero)
Fusion ~16-18 years
OC patella
Primary: (3-6 years)
Secondary (normal variant) only in somecases (bi-partite patella)
Fully ossified during puberty
OC proximal tibia
Primary: diaphysis/shaft (7th week in utero)
Secondary:
proximal epiphysis/tibial plateau (1 year)
Tibial tuberosity apophysis (10-12 years)
Fusion ~16-18 years
OC proximal fibula
Primary: diaphysis/shaft (8th week in utero)
Secondary: proximal epiphysis/head (3-4years)
Fusion ~16-18 years
menisci description
C-shaped fibrocartilage rings on tibial condyles
Attached anteriorly/posteriorly on tibial spines
Increase surface area of articular surface of tibia to improvecongruence with femur
Commonly injured/torn
synovial membrane/capsule description
Forms intra-articular region of knee
Attaches to tibial/femoral articular surfacesand menisci
Passes anterior to cruciate ligaments
Filled with synovial fluid to act as lubricant tomovement
Bone surfaces covered by hyaline cartilage
synovial membrane/capsule
Friction further reduced by:
several extensions/recesses of capsule
Presence of synovial bursae
Infra-patella (Hoffa’s) fat pad
Supra-patella bursa most significant in knee effusions
Bursitis a common clinical presentation
knee effusions
Caused by increase in fluid within the joint capsule:
Blood
Pus
Synovial fluid
Presents as oval opacity in supra-patella bursa on lateral
Non-specific but In trauma it’s presence is suspicious for‘injury’
Presence of fat and blood level indicates definite intra-articular fracture: lipohaemarthrosis
fibrous joint capsule
Encloses, Supports, and strengthens the joint
Blends with medial meniscus and collateralligament
Lateral structures less fixed and more mobile
Connects medial/lateral patella to provide
ligaments
Number of major and less significant ligaments providemuch of the knee’s strength and stability:
Patella ligament( ?tendon)
Collateral (medial/lateral)
Cruciate (anterior/posterior)
more likely to rupture in adults than bony injury (opposite in paediatrics)
patella ligament
Continuation of quadriceps femoris tendon
Connects apex of patella and tibial tuberosity
Covered anteriorly/posteriorly to reduce friction:
Superficial/deep infrapatellar bursa
Hoffa’s fat pad
collateral ligaments
Medial (tibial) collateral (MCL)
Flat and broad
Connected to fibrous capsule/meniscus
Lateral (fibular) collateral (LCL):
More like a rope
Separate from capsule by bursa
Prevent medial/lateral movement at knee joint
Consider injury in side impact forces on
cruciate ligaments
Cross’ in the intercondylar region
Provide anterior/posterior stability preventing tibiamoving
Anterior (ACL):
Prevents anterior movement of tibia
Lateral femoral condyle to anterior tibial spine
Posterior (PCL):
Prevents posterior movement of tibia
Medial femoral condyle to posterior tibial spine
Injury commonly associated with other structures;clinical examination and MRI
neurovascular
Popliteal fossa:
transition between region of thigh and leg
Formed by space between muscles in posterior knee
Neurovascular structure pass through this
Branches from femoral/popliteal artery whichdivides into anterior/posterior tibial (forms ananastomosis)
Sciatic nerve divides into tibial and commonfibular
Small saphenous and tibial veins combine toform femoral vein
