myology of the foot and lower leg Flashcards
what are the 4 compartments of extrinsic musculature of the lower leg
-superficial posterior
-deep posterior
-lateral
- anterior
what muscle group is found in the superficial posterior compartment
plantarflexors
what muscle group is found in the deep posterior compartment
toe flexors/ invertors/ plantarflexors
what muscle group is found in the lateral compartment
evertors/ plantarflexors
what muscle group is found in the anterior compartment
dorsiflexors/ invertors/ toe extensors
what nerve supplies the posterior compartments
tibial nerve S1, 2
what nerve supplies the anterior compartment
deep peroneal nerve
what nerve supplies the lateral compartment
superficial peroneal nerve
define an extrinsic muscle
a muscle whose origin is distant from its area of action
what is a retinaculum
a band of thickened, deep fascia
what are the 4 retinaculae of the ankle
-flexor
superior extensor
inferior extensor
peroneal
what are the functions of the retinaculae
-binds tendons down to bone
-prevents bowstringing of muscles (where force is only produced by tendons) allowing muscles to produce good force
describe the plantar aponeurosis (fascia)
thick dense connective tissue on sole of foot
originates from tuberosity of calcaneus to metatarsal heads
bears 15% of load on foot
stores energy for propulsion
what muscles are found in the 1st layer of the foot
abductor hallucis
flexor digitorum brevis
abductor digiti minimi
what muscles are found in the 2nd layer of the foot
lumbricals
quadratus plantae
what tendons are found in the 2nd layer of the foot
flexor digitorum longus
flexor hallucis longus
what muscles are in the 3rd layer of the foot
adductor hallucis
flexor digiti minimi brevis
flexor hallucis brevis
what muscles are in the 4th layer of the foot
dorsal interossei
plantar interossei
what tendons are in the 4th layer of the foot
peroneus longus
tibialis posterior
gastrocnemius action
plantarflexion and knee flexion
gastrocnemius origin
medial head- medial supracondylar ridge and adductor tubercle of femur
lateral head- lateral condyle of femur
gastrocnemius insertion
via tendocalcaneus into posterior surface calcaneus
soleus origin
soleal line on posterior surface of tibia
soleus insertion
via tendocalcaneous with gastroc into posterior surface calcaneus
gastrocnemius and soleus nerve supply
tibia nerve S1,2
tibialis posterior action
inverts and plantarflexes foot
tibialis posterior origin
upper part posterior surface of tibia and fibula, interosseous membrane
tibialis posterior insertion
tubercle of navicular and medial cuneiform with expansions to all tarsal bones except talus
tibialis posterior nerve supply
tibial nerve L4,5
Flexor hallucis longus action
plantarflexes big toe and then ankle
flexor hallucis longus origin
lower 2/3rds posterior fibula
flexor hallucis longus insertion
plantar surface base of distal phalanx of hallucis
flexor hallucis longus nerve supply
tibial nerve s1,2
tibialis anterior origin
upper 2/3rds lateral surface tibia and interosseous membrane
tibialis anterior insertion
medial side of medial cuneiform and base 1st metatarsal
tibialis anterior nerve supply
deep peroneal nerve L4, 5
