The leg muscles can be divided into two groups: those that
move the feet and those that allow you to wiggle your toes.
The tibialis anterior, fibularis longus, gastrocnemius, so-
leus, and tibialis posterior move the ankle. The extensor
digitorum longus and flexor digitorum longus allow move-
ment of the toes. See Figure 6.24 for an illustration of
these muscles and details about their origins, insertions,
and actions.
CONCEPT CHECK
1.
During
movement, what is the role of the agonist?
2.
Which
muscle groups are responsible for
breathing?
3.
Where
would you find the gastrocnemius muscle?
Muscles of the leg that move
the feet and toes • Figure 6.24
-Fibula-
• Tibia
Tibialis anterior
Gastrocnemius
Fibularis longus
Soleus
Extensor -
digitorum longus
' Flexor digitorum
longus
Fibula -
Right lateral superficial view
Anterior superficial view
Muscle
Origin
Insertion
Action
Muscles of the leg that move the feet
Tibialis anterior
(tib'-e-A-lis)
Tibia
First metatarsal and first cuneiform
Dorsiflexes and inverts (supinates) foot
Fibularis longus
(fib-ü-LAR-is LON-gus)
Fibula and tibia
First metatarsal and first cuneiform
Plantar flexes and everts (pronates) foot
Gastrocnemius
(gas'-trok-NË-më-us)
Femur
Calcaneus by means of calcaneal
(Achilles) tendon
Plantar flexes foot; flexes leg at knee
joint
Soleus
(SO-le-us)
Fibula and tibia
Calcaneus by means of calcaneal
(Achilles) tendon
Plantar flexes foot
Tibialis posterior
(tib'-e-A-lis)
Tibia and fibula
Second, third, and fourth
metatarsals; navicular; all three
cuneiforms; and cuboid
Plantar flexes and inverts foot
Muscles of the leg that move the toes
Extensor digitorum longus
(eks-TEN-sor di'-ji-TOR-um LON-gus)
Tibia and fibula
Middle and distal phalanges of
each toe (except great toe)
Dorsiflexes and everts foot; extends
toes
Flexor digitorum longus
(FLEK-sor)
Tibia
Distal phalanges of each toe
(except great toe)
Plantar flexes foot; flexes toes
184 CHAPTER 6
The Muscular System
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