1. inferior tibiofibular jnt. tibiotalar jnt. lateral
Talocrural joint
inferior tibiofibular jnt.
tibiotalar jnt.
lateral
fibula
calcaneus
Subtalar joint
aka talocalcaneal
between talus and calcaneus
cuboid
Midtarsal joint
between calcaneus and cuboid on lateral side
between talus and navicular on the medial side
tibia
talus
calcaneus
navicular
medial
Ankle & Foot

2. Talocrural Joint
Articulation between the tibia and fibula (inferior tibiofibular joint) and between the tibia and the talus (tibiotalar joint).
This joint is responsible for plantar flexion and dorsiflexion and some abduction/adduction.
The axis of rotation is a line between the two malleoli.

3. Subtalar Joint Allows pronation/supination and rotation.
The talus articulates with the calcaneus anteriorly, posteriorly and medially.
The axis of rotation runs diagonally from the posterior, lateral, plantar surface to the anterior, medial, dorsal surface.
The orientation of this axis makes pronation/supination triplanar with reference to the cardinal planes.

4. Pronation/Supination
Open Chain calcaneal eversion calcaneal inversion
abduction adduction
dorsiflexion plantar flexion
Closed Chain calcaneal eversion calcaneal inversion
talar adduction talar abduction
plantar flexion dorsiflexion
calcaneus moves on talus
talus moves on calcaneus

5. Tibial Rotation
The subtalar joint can be likened to the action of a mitered hinge (Inman and Mann, 1973).
The orientation of the subtalar joint axis causes the tibia to internally rotate during pronation and externally rotate during supination.
Thus, the tibia internally rotates with pronation or knee flexion and externally rotates with supination or knee extension.
It is important that knee flexion and pronation occur in synchronization (as well as knee extension and supination).

6. Midtarsal Joint
During pronation, the axes of these two joints are parallel, this unlocks the joint and creates a hypermobile foot that can absorb shock. During supination the axes are not parallel and this joint becomes locked allowing efficient transmission of forces.
Actually consists of two joints: the calcaneocuboid on the lateral side and the talonavicular on the medial side.

7. Foot Orientation

8. A forefoot valgus exists when the forefoot is everted relative the rearfoot. This is not as common as forefoot varus.
A forefoot varus exists when the forefoot is inverted to the rearfoot. This is the most common cause of excessive pronation.

9. A rearfoot valgus exists when the rearfoot is everted.
A rearfoot varus exists when the rearfoot is inverted. This can increase maximum pronation.

10. Ligaments
Lateral side of ankle accounts for 85% of ankle sprains

11. Arches of the Foot
Fascia
Plantar surface
There are 3 arches in the foot that contribute to support and shock absorption. These arches are maintained by the shape of the tarsal and metatarsal bones, ligaments and plantar fascia.

12. Arch Types
Feet are often classified according to the height of the medial arch.
Normal
high-arched or pes cavus
flat-footed or pes planus
Arches can also be rigid or flexible.
High-arched, rigid feet make poor shock absorbers.
Flat-footed, flexible arches often allow excessive pronation.

13. Plantar Flexors Gastrocnemius Soleus NOTE: 1) Soleus lies deep to
2) Both insert into
the calcaneal
tendon aka
Achilles tendon
Posterior View
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14. Assistant Plantar Flexors
Note: Their tendons pass
posteriorly to the malleoli
Flexor
Digitorum
Longus
Flexor
Hallucis
Longus
Tibialis
Posterior
Peroneus
Brevis
Peroneus
Longus
Plantaris
Note:
insertion
is wrong!
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15. Dorsiflexion tibialis anterior extensor hallucis longus (deep to ext.
digitorum
longus)
extensor
digitorum
longus
peroneus tertius
(usually very
close to extensor
digitorum longus
and often
considered as
part of this muscle)

16. Invertors primary extensor flexor flexor hallucis digitorum tibialis
NOTE: Muscles pass
to the medial side of
the foot!
primary
extensor
hallucis
longus
flexor
digitorum
longus
flexor
hallucis
longus
tibialis
anterior
tibialis
posterior
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17. Evertors primary extensor digitorum longus peroneus brevis peroneus
tertius
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18. Causes of Excessive Pronation
Q-angle greater than 20 degrees
tibial varus greater than 5 degrees
rearfoot varus greater than 2 degrees
forefoot varus greater than 3 degrees
plantar flexed first ray
weak medial arch
tight gastrocnemius and soleus or a short Achilles tendon
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19. The Problem with Excessive Pronation
Excessive or prolonged pronation during the support phase will disrupt the normal tibial-femoral rotation relationship at the knee. The tibia continues to internally rotate with the prolonged pronation while the knee is extending. Knee extension is normally associated with external tibial rotation.
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