Anterior/Lateral Leg Flashcards
tibial plateau
@superior surface tibia
has medial and lateral condyles
-intercondylar eminence b/t (projections fit into intercondylar fossa of femur)
-minisci + ACL + PCL will attach
fibula
basically just a mucle attachment site, not weight wearing
interosseous membrane
function
- stabilizes tib and fib
- physical barrier b/t ant/post but gaps at top and bottom for vessels and nerves travel b/t compartments
- muscles attach
separates ant/post compartment
superficial fascia
aka subQ tissue w/ veins + cutaneous N + lymph vessels/nodes + fat
main superficial veins= great saphenous V (medial) + smaller/lesser saphenous (post)
deep fascia
aka crural fascia
-cont w/ fascia lata/popliteal fascia/deep fascia foot
> 3 intermuscular septa + retinacula (ankle)
retinacula
bands of CT that overlie tendons and hold in place
retain tendons
leg compartments
general
- anterior
- lateral
- posterior (super and deep)
thigh has ant/med/post
anterior compartment
ankle dorsiflexors + toe extensors
motor by deep fibular N
blood by anterior tibial A
lateral compartment
foot evertors (main) + plantarflexion (weak)
motor by superficial fibular N
blood by perforating branches (no major A)
posterior compartment
superficial = ankle plantarflexion
deep = toe flexor
motor by tibial N
anterior compartment muscles
- tibialis anterior
- extensor hallucis longus (EHL)
- extensor digitorum longus (EDL)
- fibularis tertius
foot drop
injury to deep fibular N = can’t dorsiflex so toes not clear the ground when walking
can also occur w/ injury to common fib N or tibialis anterior muscle
tibialis anterior
main ankle dorsiflexor and foot invertor
most ant and superficial muscle
og @lateral tibia + anterior surface of IM
in @medial cuneiform + base of MT1 (medial)
IM = interosseous membrane
shin splints
overuse of tibialis anterior aka repeated microtrauma = small tears in periosteum lateral to tibia
swelling/edema of periosteum (bc hard to drain fluid) + pain in middle half of leg
common in runners bc constant dorsiflexion
extensor hallucis longus
EHL
main extensor of hallux + assist dorsiflex ankle
deepest muscle in anterior compartment
og @ant surface fibula + ant IM
in @ distal phalanx of hallux
hallux is big toe/MT1
extensor digitorum longus
EDL
main extensor of digits II-V + assist ankle dorsiflexion
og @ lateral condyl tibia + ant fibula + IM
in @ middle + distal phalanges of II-V
fibularis tertius
assist dorsiflex ankle + assist lateral compartment everting foot
og @ distal end fibula + IM
in @ base of MT5
longus and brevis are in lateral compartment
IM = interosseous membrane
anterior compartment syndrome
bleeding/swelling = inc pressure so no room for extra fluid
-deep fibular N gets compressed = weaken dorsiflexion and pain down leg
-dec blood flow = ischemia
from trauma or injury, treat w/ fasciotomy
lateral compartment muscles
- fibularis longus
- fibularis brevis
fibularis brevis
deep to longus
og @ distal 2/3 lateral fibula
-tendon hooks behind lateral malleolus like a pulley to redirect force
in @ base of MT5
fibularis longus
superficial to brevis
og @ head + prox 2/3 lateral fibula
-tendon also hooks behind lateral malleolus
in @ medial cuneiform + base of MT1
-wraps around cuboid bone anteromedially
combined fibularis actions
retinacula changes direction of pulling forces to ensure insertion is puled to origin
lateral margin of foot raises/medial margin drops (eversion) OR
heel pull up/front half drops (plantarflex)
eversion mechanism
brevis pulls lateral side up
longus pulls medial side down
innervation
sciatic > common fibular N > split @under neck of fibula =
deep fibular (ant comp, post div L4-S1) + superficial fibular N (lat comp, post div L5-S2)
cutaneous innervation
- saphenous N from femoral=medial leg
- lateral sural cutaneous N= prox 2/3 lateral
- superficial fibular N= distal 1/3 anterolat leg + dorsum foot
common fibular N injury
very superficial as crosses head/neck fibula
if damage proximal to split = affects all distal/downstream branches aka all ant muscles + all lat muscles + skin ant/lat/most dorsum
weak dorsiflex, eversion, extend toes
arterial supply
popliteal A split into posterior/anterior tibial A
anterior tibial A contributes to genicular anastomosis
anterior tibial + fibular + posterior tibular contribute to anastomosis around ankle
superficial veins
-great saphenous V drain to femoral V
-small/lesser saphenous drain to popliteal V
perforating veins penetrate crural fascia so allow superficial to drain into deep veins
deep veins
in accompanying veins/venae comitantes form aka not just a singular tube (two smaller instead)
lymphatics
ant lymph vessels travel medial/superior to inguinal region
>drain to superficial inguinal nodes>deep inguinal nodes
some parts lateral travel post/super to popliteal fossa
>drain to superificial popliteal nodes > deep inguinal nodes
