Leg and Knee Flashcards
tibia vs fibula
tibia is larger, weight bearing and articulates w/ femoral condyles
fibula- smaller and more lateral, mainly for muscular attachment and ankle stabilization
tibial tuberosity
attachment site for patellar tendon
medial malleolus
medial projection of distal tibia
anterior intercondylar area and posterior intercondylar area fn
ACL and PCL attachment
describe knee joint structure
largest synovial joint but mechanically weak- needs lots of muscles and ligaments
primaryly hinge joint, although some gliding, rolling, rotation
most important muscles for knee stabilization
quads
patellar retinaculum
expansion of quad tendon around anterior aspect of knee
ligaments helping strong fibrous capsule around knee
LCL
MCL
oblique popliteal (expansion of semimembranosus tendon)
arcuate popliteal (arches over popliteus)
LCL and MCL more clinically relevant
LCL
from lateral femoral condylyle to head of fibula, easily palpable
MCL
flat band like
deep fibers attached to medial meniscus
MCL and medial meniscus commonly injured simultaneously
role of cruciate ligaments
join femur and tibia, added stability
describe ACL role
slightly relaxed when knee is flexed, tighter when extended
prevents femur from sliding posteriorly on tibia and helps prevent knee hyperextension (injuries tend to happen in extended position)
ACL rupture injuries, physical exam finding, concurrent terars
usually sports related w/ extension and over rotation
tibia can be manually displaced anteriorly, anterior drawer sign
often as unhappy triad- usually w/ tears of medial meniscus and MCL
PCL role
tightens during knee flexion, prevents femur from sliding anteriorly on tibia
menisci strucuture and fn
fibrocartilagenous plates on superior articular surface of tibia
shock asorbers, deepen joint cavity
menisci injuries
usually during torsional twisting- limited blood supply so wont heal on their own
contrast medial and lateral menisci
medial- larger and c shaped, attached to MCL fibers
lateral- smaller and circular, more mobile and therefore less likely to get injured and not fused to LCL (popliteus tendon is b/w these structures)
PCL injuries
force on antior of tibia during flexion
two main branches of sciatic nerve
tibial and common fibular
contrast tibial and fibular nerves
tibial- thru popliteal fossa, innervates muscles in posterior compartment
common fibular- divides into superficial (lateral compartment) and deep (anterior compartment)
3 main compartments of leg
anterior- deep fibular
lateral- superficial fibular
posterior (technically 2, superificial and deep)- tibial nerve
superficial posterior muscles, fn
plantarflexors of ankle joint
gastrocnemius- 2 heads and crosses two joints, rapid plantar flexion
soleus- deep to gastroc, powerful but slow plantarflexor
plantaris- long thin tendon, maybe proprioception, used for grafts
tibial nerve S1,2 (S1 S2 I’m taller than you; help stand on toes)
triceps surae
2 heads of gastroc and soleus muscle- has a common tendon forming achilles tendon inserting into calcaneal tuberosity
deep posterior compartment muscles, fn
plantarflex the ankly, flex toes and invert foot
all innervated by tibial,
tibialis posterior- inserts into several pedal bones and support longitudinal arch, inversion of foot and plantarflexion
flexor digitorum longus- divides into 4 tendons w/i foot, inserts into base of distal planages and flexes toes
flexor hallucis longus- “push off” muscle, inserts distal phalanx and flexes big toe
deep posterior muscles entry into foot
tendons pass trhur tarsal tunnel along w/ sciatic nerve
Tom, Dick and Harry muscles and nerve roots of tibial nerve
tibialis posterior (L4,5), flexor digitorum longus (S2,3), flexor hallucis longus (S2,3)
tarsal tunnel structures
from medial to lateral
tom, dick AN’ (posterior tibial Artery and tibial Nerve) harry underneath flexor retinaculum
common fibular nerve branches into which compartments, sensory innervation
divides into branches after coursing around head of fibula
superficial- lateral compartment, sensory to dorsum of foot
deep fibular nerve- anterior compartment and sensory b/w big and second toe
lateral compartment muscles
eversion of foot
fibularis longus- tendon passes thru groove in cuboid, inserts into medial cuneiform and 1st metatarsal
fibularis brevis- inserts base of 5th metatarsal
superficial fibular nerve (L5, S1)
anterior compartment muscles
dorsifexion of foot/toes
tibialis anterior- powerful, primary dorsiflexor
extendosr digitorum longus- extends digits, inserts into extensor expansion on toes, also dorsiflexes
extensory hallucis longus- extends hallux, also dorsiflexion
deep fibular nerve- L4,5 and S2
(fibularis tertius dorsiflexes and everts)
neurovasculature of anterior compartment
deep fibular nerve and anterior tibial artery go b/w anterior compartment muscles, cross anterior to ankle and onto foot
anterior tibial artery becomes dorsalis pedis artery, vascularize foot
drop foot
anterior muscles weak or paralyzed- trauma to common fibular nerve or deep fibular erve or L4/5 disc herniation
compensate w/ steppage gait- hyperflexion of the hip to raise foot during swing phase of gait, often w/ audible slap
cause of common fibular nerve injury
fracture of head of fibula
compartment syndrome
can happen in any muscular compartment- swelling compresses neurovasculature w/i compartment, causing diminished pulse, pain, extreme pain in anterior compartment muscles
from trauma, overuse
location of dorsalis pedis, patho
palpated lateral to EHL tendon, diminshed pulse can mean occlusive disease or anterior compartment syndrome
ankle joint bones, stability
hinge synovial
b/w distal tibia and fibula and the talus- distal tibia and fibula form a “mortise” for the trochlea of the talus
anterior surface of trochlea is wider than posterior- more stable in dorsiflexion
lateral ankle ligaments (3)
anterior talofibular*(most commonly injured during sprain)
calcaneofibular
posterior talofibular
stabilize during inversion, 90 degrees apart and arise from distal fibula
medial ankle ligaments
deltoid ligaments- stronger than lateral, stabilize during eversion and arise from medial malleolus
stronger than bone, will evulse medial malleolus before tearing
lateral ankle sprain
usually anterior talofibular, when pts land w/ foot plantarflexed and inverted
talus becomes unstable w/i ankle mortise and easily twists or rolls, disrupting lateral ligaments
