Download Muscles of the Ankle

Myology
Myology of the
Ankle
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Anatomical Review: Tibia and Fibula
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Tarsals, Metatarsals, and Phalanges
• Tarsals:
– Consists of seven small bones called tarsals
– Tarsals form the posterior half of the foot and heel.
– Bones: Talus, calcaneus, cuboid, navicular, and three
cuneiforms
• Metatarsals
– Same as the palm there are five metatarsals numbered I through
V, with number I being the great toe
– Each metatarsal has a base, shaft, and a head
• The base articulates with the tarsals while the head
articulates with the phalanges.
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• Toes:
– 14 phalanges in each foot
– Each phalanx also consists of a base, shaft, and head
– The great toe only contains two phalanges, a proximal and
distal one
– The remaining toes each contain three phalanges (proximal,
middle, and distal)
– Joints formed between phalanges:
• Proximal interphalangeal joint (PIP)
– Joint formed between proximal and middle phalanges
• Distal interphalangeal joint (DIP)
– Joint formed between middle and distal phalanges
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Anatomical Review: Foot
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Arches of the Foot
(See plate 5 for diagram of the arches of the foot)
Functions:
1. Support the weight of the body
2. Provide an ideal distribution of the weight of the body over the
hard and soft tissue of the foot.
3. Provide leverage while walking.
•
•
Arches are not rigid, they yield as weight is applied and spring back when weight is
lifted thus helping absorb shock.
Arches develop about the age of 13
3 Arches:
1. Medial longitudinal arch: Originates at the calcaneus, rises to the talus, and
descends through the navicular, the three cuneiforms, and the heads of the three
medial metatarsals.
2. Lateral longitudinal arch: Originates at the calcaneus, rises to the cuboid, and
descends to the heads of the lateral two metatarsals.
3. Transverse arch: Formed by the navicular, three cuneiforms, and bases of the five
metatarsals.
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Anatomical Review: Arches of the
Foot
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Articular Anatomy: Ankle
Ankle Joint: Also known as the talocrural joint
• Formed by the articulation of:
1. Medial malleolus of the distal tibia and talus
2. Lateral malleolus of the distal fibula and talus
• Considered to be a hinge joint
Intertarsal joints: (3 articulations)
1. Subtalar joint: articulation between talus and calcaneus
2. Talocalcaneonavicular joint: articulation between talus,
calcaneus, and navicular.
3. Calcaneocuboid joint: articulation between calcaneus and
cuboid
• These are considered to be planar (gliding) joints as the articular
surfaces are flat or slightly curved.
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Soft Tissue of the Ankle and Foot
Articular Capsule: composed of fibrocartilage, thin anteriorly and
posteriorly. Extends from the malleoli to the talus.
Deltoid Ligament: Triangular shaped ligament on the medial aspect
of the ankle. Apex is located at the medial malleolus. Base attaches
to the talus, navicular, and calcaneus. Clinically, a very strong
ligament. With eversion injuries the bones of the leg/ankle will most
likely fracture before this ligament will tear.
Plantar Calcaneonavicular (Spring) Ligament: Extends from the
medial aspect of the calcaneus to the navicular.
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Soft Tissue of the Ankle and Foot
Lateral Ligaments: (considered some of the weakest ligaments in
the body)
a. Anterior Talofibular Ligament: Extends from the lateral
malleolus to the talus
b. Posterior Talofibular Ligament: Extends from the
lateral malleolus to the talus
c. Calcaneofibular Ligament: Extends from the lateral
malleolus to the lateral aspect of the calcaneus.
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Ankle and Foot Ranges of Motion
Each student should be able to describe and
demonstrate the following movements:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Ankle Dorsiflexion
Ankle joint
Ankle Plantarflexion
Ankle Inversion
Intertarsal joint
Ankle Eversion
Toe Flexion
Toe Extension
Same as the fingers
Toe Abduction
Toe Adduction
Hallux Flexion, Extension, Abduction, and Adduction
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Palpation of the Ankle and Foot
Lateral and Medial Malleoli: Seated, palpate the large knobs on either side of the ankle.
Note that the broader, medial malleolus is located at the distal end of the tibia while the more
slender lateral malleolus is part of the fibula.
Calcaneus: Seated, again locate the malleoli. Slide your fingers toward the heal and palpate
the shape of the calcaneus.
Cuneiforms: Seated, find the base of the 1st metatarsal. Then slide proximally into the
“ditch”
of the tarsometatarsal joint. Then continue proximally onto the surface of the medial
cuneiform. To find the middle and lateral cuneiform, slide your fingers laterally along the
dorsal surface of the foot.
Navicular: Seated, again locate the base of the 1st metatarsal. Slide along the medial side of
the foot, moving proximally across the surface of the medial cuneiform onto the navicular.
Cuboid: Seated, locate the 5th metatarsal bone. Slide your finger along the 5th metatarsal to
its base (which is expanded laterally). Continuing along the lateral side of the foot, slide your
finger off the base of the 5th metatarsal onto the lateral border of the cuboid.
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Muscles that move the ankle
Tibialis Anterior
Extensor Digitorum Longus
Extensor Hallucis Longus
Peroneus (Fibularis) Tertius
Peroneus Longus
Peroneus Brevis
Anterior Compartment
Lateral Compartment
Gastrocnemius
Soleus
Plantaris
Popliteus
Flexor digitorum longus
Flexor hallucis longus
Tibialis posterior
Posterior Compartment
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Tibialis Anterior
O: Entire shaft of the tibia
I: 1st Cuneiform/1st Metatarsal
A: Dorsiflexes and inversion of the
ankle.
N: Deep peroneal nerve
Clinically, the Tibialis Anterior is
related to shin splints, causing
anterolateral leg pain
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Extensor Digitorum Longus
O: Proximal anterior fibula
I: Middle and distal phalanges of the
lateral four toes
A: Extension of toes 2 through 5 and
assists in dorsiflexion of the ankle.
N: Deep peroneal nerve
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Extensor Hallucis Longus
O: Distal 1/3 of the anterior surface
of the fibula and interosseous
membrane
I: Base of the distal phalange of the
big toe.
A: Extends the great toe
and assists in dorsiflexion of the
ankle.
N: Deep peroneal nerve
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Peroneus (Fibularis) Tertius
O: Anterior surface of the distal
fibula
I: Base of the 5th
metatarsal
A: Dorsiflexion and
eversion of the foot
N: Deep peroneal nerve
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Peroneus (Fibularis) Longus
O: Proximal surface of the fibular
head and shaft of the fibula
I: Muscle cross under the foot from
lateral to medial inserting onto the
base of the 1st metatarsal and
medial cuneiform.
A: Eversion of the foot and assists in
plantarflexion of the ankle.
N: Superficial peroneal nerve
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Peroneus (Fibularis) Brevis
O: Lower 2/3 of lateral shaft of the
fibula
I: Base of the 5th metatarsal
A: Eversion of the foot and assists in
plantarflexion of the ankle.
N: Superficial peroneal nerve
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Gastrocnemius
O: Posterior surface of the medial and
lateral condyles
I: Posterior surface of the
calcaneus via the Achilles
tendon.
A. Knee: Flexion
Ankle: Plantarflexion
N. Tibial nerve
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Soleus
O: Soleal line of tibia and fibular
head.
I: Calcaneus via the Achilles tendon.
A.
Plantarflexion of the foot
N: Tibial nerve
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Plantaris
O: Lateral epicondyle of the femur
I: Calcaneus via the Achilles
tendon.
A: Plantarflexion of the foot and flexion
of the knee
N: Tibial nerve
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Popliteus
O: Lateral condyle of the femur
I: Posterior proximal shaft of the
tibia
A: Initiates knee flexion by medial
rotation of the tibia to unlock the
knee
N: Tibial nerve
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Flexor Digitorum Longus
O: Posterior surface of mid-shaft of
the tibia
I: Plantar surface of toes 2-5
A: Flexion of the toes, Plantarflexion and
inversion of the ankle
N: Tibial nerve
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Flexor Hallucis Longus
O: Posterior surface of fibula
I: Plantar surface of the great toe
A: Flexion of the great toe
Plantarflexion and inversion of
the ankle
N: Tibial nerve
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Tibialis Posterior
O: Posterior aspect of proximal tibia
and fibula
I: Plantar surface of the foot
(navicular, adjacent tarsals, and
metatarsals)
A: Plantarflexion and inversion of
the ankle
N: Tibial nerve
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