Anatomy of the leg Flashcards
What is an ankle sprain
Torn ligament fibres
Often results from twisting the
ankle on a weight-bearing
plantarflexed foot. Illustrated is
an inversion injury resulting in a
torn anterior talofibular ligament
(part of the lateral ligament)
What are the muscles of the posterior leg (gastrocnemius)
- Origin – posterior
surface of distal femur
above medial condyle
(medial head) and
lateral femoral condyle
(lateral head) - Insertion – calcaneus
via calcaneal tendon - Innervation – tibial
nerve (S1, S2) - Action – flexes knee and
plantarflexes foot
What are the muscles of the posterior leg (plantaris)
Origin – inferior lateral
supracondylar line of
femur and popliteal
tendon
* Insertion – calcaneus
via calcaneal tendon
* Innervation – tibial
nerve (S1, S2)
* Action – flexes knee and
plantarflexes foot
What are the muscles of the posterior leg (soleus)
Origin – soleal line of
tibia, tendinous arch,
posterior fibula
* Insertion – calcaneus
via calcaneal tendon
* Innervation – tibial
nerve (S1, S2)
* Action – plantarflexes
foot
Describe the deep posterior leg muscle: flexor hallucius longus
FLEXOR HALLUCIS LONGUS
* Origin – posterior fibular and
interosseous membrane
* Insertion – plantar surface of
distal phalanx of digit I
* Innervation – tibial nerve (S2, S3)
* Action – flexes big toe
Describe the deep posterior leg muscle: tibialis posterior
TIBIALIS POSTERIOR
* Origin – posterior surface of
interosseous membrane and
adjacent tibia and fibula
* Insertion – navicular and medial
cuneiform
* Innervation – tibial nerve (L4, L5)
* Action – plantarflexes and inverts
foot, supports medial arch
Describe the deep posterior leg muscle: flexor digitorum longus
FLEXOR DIGITORUM LONGUS
* Origin – posterior tibia
* Insertion – plantar surface of
distal phalanges of digits II - V
* Innervation – tibial nerve (S2, S3)
* Action – flexes lateral four toes
What are muscles of the lateral leg (fibularis longus)
FIBULARIS LONGUS
* Origin – upper lateral surface of
fibula
* Insertion – plantar surface of
medial cuneiform and MT I
* Innervation – superficial fibular
nerve (L5, S1, S2)
* Action – eversion and
plantarflexion of foot, supports
arches
What are the muscles of the lateral leg (fibularis brevis)
FIBULARIS BREVIS
* Origin – lower lateral surface of
fibula shaft
* Insertion – base of MT V
* Innervation – superficial fibular
nerve (L5, S1, S2)
* Action – eversion of foot
What are the muscles of the anterior leg (tibialis anterior)
TIBIALIS ANTERIOR
* Origin – lateral tibia and
interosseous membrane
* Insertion – medial cuneiform and
base of MT I
* Innervation – deep fibular nerve
(L4, L5)
* Action – dorsiflexion of foot,
inversion of foot, supports medial
arch
What are the muscles of the anterior leg (extensor digitorum longus)
- Origin – medial surface of proximal
fibula and lateral tibial condyle - Insertion – dorsal expansions to
distal and middle phalanges of digits
II - V - Innervation – deep fibular nerve
(L5, S1) - Action – extends digits II – V and
dorsiflexes foot
What are the anterior leg muscles (fibularis tertius)
FIBULARIS TERTIUS
* Origin – distal medial surface of
fibula
* Insertion – dorsomedial surface of
base of MT V
* Innervation – deep fibular nerve
(L5, S1)
* Action – dorsiflexion and possible
eversion of foot
What are the anterior leg muscles (extensor hallucis longus)
EXTENSOR HALLUCIS LONGUS
* Origin – medial surface of middle
fibula and interosseous membrane
* Insertion – dorsal surface of base of
distal phalanx of digit I
* Innervation – deep fibular nerve
(L5, S1)
* Action – extends big toe and
dorsiflexes foot
What is the blood supply to the posterior and lateral component of the leg
Popliteal artery
- Starts at adductor hiatus and
passes under tendinous arch - Divides into anterior and
posterior tibial arteries - Anterior tibial a. passes
through hole in upper
interosseous membrane - Posterior tibial a. supplies
posterior and lateral
compartments, enters foot via
tarsal tunnel, and gives off: - Fibular artery – supplies posterior
and lateral compartments, and
gives off perforating branch
through lower aperture to
anterior tibial artery
What is the blood supply to the anterior and lateral component of the leg
Anterior tibial artery
- Originates from popliteal in
posterior compartment and
passes through upper aperture
of interosseous membrane - Supplies anterior compartment
muscles (and perforating
branches to lateral) - Joined by perforating branch of
fibular artery - Gives off anterior medial and
anterior lateral malleolar
arteries - Continues into foot as dorsalis
pedis
