Download The tibialis anterior crosses over the top, medial surface of the foot

The tibialis anterior crosses over the top, medial surface of the foot and goes
underneath to insert onto the plantar surface of the 1 st cuneiform and 1st metatarsal.
It is the superficial muscle of the shin. “Shin splints” are caused when the tibialis
anterior becomes irritated from overuse of running on hard surfaces because it
causes the muscle to swell and the blood supply reduces—causing it to be painful.
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Extensor Digitorum Longus is lateral to the tibialis anterior. Remember the term
“digitorum” refers to digits 2-5. Notice the anterior muscles of the ankle do
dorsiflexion (bring the top of the foot up). The posterior muscles of the ankle will do
plantar flexion (toes go down).
2
Hallucis is the term that means big toe. If you see the term “hallucis” you know it will
be moving the big toe. The Extensor Hallucis Longus lies between and partly deep to
the tibialis anterior and extensor digitorum longus.
3
The peroneus muscle group contains 3 muscles. The peroneus tertius is the smallest
and is located more anteriorly than the other 2. All of the peroneus muscles do
eversion. The peroneus tertius since it is located more anterior will do dorsiflexion in
addition to eversion.
4
The peroneus longus and brevis are located laterally. They both run underneath the
lateral malleolus which allows them to do eversion and plantar flexion NOT
dorsiflexion like the peroneus tertius. The peroneus longus runs underneath the foot
to the plantar surface and helps to stabilize the lateral ankle and the lateral
longitudinal arch of the foot. The peroneus brevis inserts onto the lateral surface of
the 5th metatarsal and lies deep to the peroneus longus.
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Now these muscles are the superficial posterior muscles of the ankle and since they
are posterior they allow plantar flexion of the ankle. Remember the gastrocnemius
has 2 heads and crosses the knee as well as the ankle. The gastrocnemius is the most
superficial calf muscle and helps to produce rapid movements that occur during
running and jumping. The soleus is still considered superficial even though it lies
deep right underneath the gastrocnemius. The gastroc, plantaris, and soleus together
are sometimes referred to as “triceps surae.”
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This is a small bellied muscle that is absent in some people. Now the gastrocnemius,
soleus, and plantaris all insert into the Achilles tendon which goes down to the
calcaneus. The Achilles tendon is the strongest, thickest tendon in the body. An
Achilles tendon rupture typically occurs during quick start and stops and once it
happens you are unable to plantar flex your ankle.
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These muscles are the DEEP posterior muscles that lie deep to the gastroc, soleus,
and plantaris. They allow plantar flexion and inversion of the ankle. The tibialias
posterior runs underneath the medial malleolus and then spreads out underneath
the foot on the plantar surface.
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Now the tibialis posterior, flexor digitorum longus, and flexor hallucis longus are
referred to as Tom, Dick, and Harry and they all allow plantar flexion and inversion.
The flexor digitorum longus is more medial and the flexor hallucis longus is more
lateral with the tibialis posterior lying in between the two. The flexor hallucis longus
is an important muscle in pushing off of surfaces during walking, running, and
jumping.
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Be sure to know the muscles for each compartment of the ankle: anterior muscles,
lateral muscles, superficial posterior muscles, and deep posterior muscles.
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Be sure to know the muscles for each compartment of the ankle: anterior muscles,
lateral muscles, superficial posterior muscles, and deep posterior muscles.
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