The Ankle and Foot Complex

How many bones are in the ankle and foot

28

How many joints are in the ankle and foot

33

How Many ligaments are in the ankle and foot

112

What are the joints of the ankle

• Proximal and distal tibiofibular joints

• Talocrural joint (the ankle joint)

• Subtalar joint

• Talocalcaneonavicular joint

• Transverse tarsal joint

• Tarsometatarsal joints

• Metatarsophalangeal joints

• Interphalangeal joint

Why does the ankle-foot complex have so many issues

• Complex structure

• Sustain large weight bearing stresses

• Multiple and somewhat conflicting functions in stability and mobility

Stability demands of the ankle-foot

• Stable base of support without unnecessary muscle activity

• Rigid lever for propulsion during gait and balance control

What are the mobility demands of the ankle-foot complex

• Conform to complex terrain

• Absorb shock from weight bearing stresses

• Accommodate rotation of the more proximal lower body joints

Explain the movements of the Distal Tibiofibular Joint

Allows for small amount of spread or accommodation at the talocrural joint.

The Distal Tibiofibular joint is supported by

• Anterior tibiofibular ligament

• Posterior tibiofibular ligament

• Inferior transverse ligament

• interosseous ligament

What kind of joint is the Talocrural joint?

How many DOF’s does it have?

• Modified Hinge joint

• 1 primary DOF: Plantarflexion/ Dorsiflexion

20 degrees of dorsiflexion is checked mainly by what muscle

Triceps surae

30-50 degrees of plantarflexion is checked by which muscles

Tibialis anterior, extensor hallucis longus and extensor digitorum longus

During dorsiflexion the Talocrural goes through what arthrokinematics

Anterior rolling and posterior gliding of the described asymmetric talus on the tibia produces dorsiflexion and abduction

During plantarflexion The Talocrural joint goes through what arthrokinematics

Posterior rolling and anterior gliding of the talus produces plantarflexion and adduction.

What are the medial ligaments of the Talocrural joint

Medial Collateral Ligament

What are some characteristics of the Medial collateral ligament (Deltoid ligament)

• Fan shaped

• Very strong

• Tibial malleolus to navicular, talus, calcaneus

• Checks medial distraction and joint end range of motion

What are the Lateral Ligaments of the Talocrural joint

• Anterior talofibular

• Posterior talofibular

• calcaneofibular ligaments

What is a difference between the MCL and LCL of the talocrural joint

Lateral ligaments are weaker and more injury prone than the MCL

The LCL checks what

Varus stress

Which Lateral ligament is the weakest an most commonly torn

Anterior talofibular

At the subtalar joint what movements are considered pronation

• Calcaneal dorsiflexion

• Abduction

• Eversion

At the subtalar joint what movements are considered supination

• Calcaneal plantarflexion

• adduction

• Inversion

What kind of joint is the subtalar joint

Modeled as a mitered hinge joint

Where do the interosseous talocalcaneal ligament and ligamentum cervicis lie?

In the tarsal canal

This image shows calcaneal valgus or varus?

Valgus

This image shows calcaneal valgus or varus?

Varus

At the subtalar joint what is the closed chain movement?

Calcaneus become fixed in the sagittal and transverse planes although must still invert and evert

Explain the movements of supination at the calcaneus, talus, and tibiofibular

• Calcaneus: Inversion

• Talus: Abduction and Dorsiflexion

• Tibiofibular: Lateral Rotation

Explain the movements of pronation at the calcaneus, talus, and tibiofibular

• Calcaneus: Eversion

• Talus: Adduction and Plantar flexion

• Tibiofibular: Medial Rotation

What are some characteristics of the Transverse Tarsal Joint

• S- Shaped joint line that transects the foot

• Divides hindfoot from the mid + forefoot

• Comprised of the talonavicular and the calcaneocuboid joint

What is the function of the Transverse Tarsal Joint

• Action permits the forefoot to remain in contact with the ground through hindfoot varus/valgus positions

• Allows for accommodation of uneven terrain and/or absorption of rotation of the lower limb

With weight bearing tibial internal rotation and subsequent subtalar pronation, the TTJ joint may do what kind of movements?

• Substantial Supination

What is the meaning of substantial supination

Maintain appropriate load bearing in forefoot on uneven terrain

With weight bearing tibial external rotation and subsequent subtalar supination, the TTJ joint may do what kind of movements?

Slight pronation

What does slight pronation mean?

Limited ability to pronate the forefoot to maintain a fixed position of the forefoot

What are some functions of the Tarsometatarsal joints

• Unique but not fully independent motion

• Each ray rotates about distinct axis

• Almost all have triplanar movement

• Allow for the cupping movement of the plantar surface of the foot

Explain the structure of the Metatarsophalangeal Joints

• Condyloid joint

• “toe joint”

• Allow for hinging and the smaller base of the support in heel rise.

What kind of joint is the metatarsophalangeal joints? How many degrees of freedom are there?

• Condyloid joint

• 2 DOF’s

What are typically movements of the metatarsophalangeal joints

• Flexion/extension

• Abduction/adduction

What are some functions of the metatarsophalangeal joints

• Hinging axis during heel lift in weight bearing

• Oblique axis through MTP joints of digits 2-5

• More evenly distributes weight bearing across the toes

Where is the load transmitted posteriorly?

Through the calcaneus to heel contact

Where is the load transmitted anteriorly?

Through the talonavicular and calcaneocuboid joints

In this image is there more force on the medial or lateral position of the foot

Medial has more force than the lateral

In Plantar arches what is considered the “keystone”

Middle Cuneiform

In plantar arches where is the greatest amount of arch

Towards the medical border

Explain the Plantar Aponeurosis Windlass Effect

• Dense fascia running the length of the foot

• Important for creating a rigid lever in gait

• As the toe lifts up, the tendon compresses together causing an arch

What is the function of the Peroneus Longus

Tendon that supports transverse arch

What muscles cause plantar flexion

• Triceps Surae

• Flexor Hallucis Longus

• Flexor Digitorum Longus

• Tibialis Posterior

• Peroneus Longus

• Peroneus Brevis

What muscles cause DorsiFlexion

• Tibialis anterior

• Extensor Hallucis Longus

• Peroneus Tertius

• Extensor digitorum longus

What Muscles cause pronation

• Peroneus tertius

• Extensor Digitorum Longus

What muscles cause supination

• Tibialis Anterior

• Extensor Hallucis Longus