Session 10: leg muscles Flashcards
name anterior leg muscles and their actions and innervation
tibialis anterior: invert foot
extensor digitorum longus: extend lateral 4 toes
extensor hallucis longus: extend big toe
all are innervated by deep fibular nerve
all dorsiflex the foot
fibularis tertius is not always present and sometimes is thought of as part of the FDL, weak dorsiflexor of the foot but mainly everts
name and describe muscle
tibialis anterior
dorsiflexes, inverts foot
deep fibular nerve
name and describe muscle
extensor digitorum longus
dorsiflexes foot, extends lat. 4 toes
deep fibular nerve
name and describe muscle
extensor hallucis longus
dorsiflexes foot, extends big toe
deep fibular nerve innervate
name and describe muscle
fibularis tertius
not always present, sometimes thought of as part of FDL
everts foot, weak dorsiflexor
deep fibular nerve
name lateral leg muscles, give attachments, innervation and action
fibularis/peroneal longus
fibularis/peroneal brevis
both are innervated by superficial fibular/peroneal nerve
the ‘longus originates from the top of the fibular whereas the ‘brevis originates further down
the ‘longus travels underneath the foot to insert to base of 1st MT and med. cuneiform, the ‘brevis inserts to 5th metatarsal
both weakly evert the foot, though their main job is to fix the medial margin of the foot when running and to prevent excessive inversion
name and describe muscle
fibularis/peroneal longus
originates from sup. lat. border of fibula and lat. tibial condyle, travels underneath foot to insert into base of 1st metatarsal and medial cuneiform
everts and plantarflexes foot, mainly prevents excessive inversion when running
innervated by superficial fibular/peroneal nerve
name and describe muscle
fibularis/peroneal brevis
originates from inf. lat. fibular shaft and inserts into 5th metatarsal
weak evertor of foot
superficial fibular/peroneal nerve
name posterior leg muscles, give general features
superficial: gastrocnemius, soleus, plantaris - insert into calcaneal tendon into calcaneum, all plantarflex the foot, the gastroc. and plantaris also flex the leg
deep: popliteus, tibialis posterior, flexor digitorum longus, flexor hallucis longus - popliteus acts on knee joint, rest act on ankle and toes
all are innervated by tibial nerve
describe gastrocnemius
two heads; med. and lat. originating from med. and lat. femoral condyles, insert into calcaneal tendon into calcaneum
filled with fast twitch muscles so used for running and jumping
innervated by tibial nerve
acts to flex leg and plantarflex foot
name and describe muscle
plantaris
originates from lateral supracondylar line of femur, absent in 10% of people, long and thin so is easily mistaken for a nerve
does the same actions as the gastrocnemius -> flexion of knee and plantarflexion of foot
inserts into calcaneal tendon into calcaneum
tibial nerve innervates
name and describe muscle
soleus
sole -> fish -> large, flat
from soleal/popliteal line of tibia and prox. fibular area -> inserts into calcaneal tendon -> calcaneum
plantarflexes foot
tibial nerve
name and describe muscle
popliteus
forms part of the base of the popliteal fossa
from lat. condyle of femur to posterior surface of tibia
lat. rotates femur on tibia to unlock knee joint so flexion can occur
tibial nerve
name and describe muscle
tibialis posterior muscle
deepest muscle and it lies between FDL and FHL
arises from the IO membrane and post. surfaces of tibia and fibula -> plantar surfaces of lat. 4 digits
inverts and plantarflexes foot, maintains med. arch of foot
name and describe muscle
flexor digitorum longus
smaller muscle than FHL
flexes 2nd-5th digits
from med. side of tibia to plantar side of lateral 4 digits
tibial nerve
name and describe muscle
flexor hallucis longus
counter-intuitively, it arises from the post. surface of the fibula (ie the opposite side of the leg to the big toe), but then inserts into the plantar surface of the distal big toe phalanx
flexes big toe
tibial nerve
