Talocrural & Subtalar Joints

What is clinically significant about the “3rd malleolus” on the tibia?

Can be involved in a tri-malleolar fracture

What is different about the lateral malleolus from the medial?

Extends more inferiorly

What is clinically significant about the lateral malleolus?

• Acts as a bony block for eversion → less eversion ROM

• Prevents medial ankle sprains (eversion sprain)

Is the talus wider anteriorly or posteriorly?

Anteriorly

What is significant about the shape of the talus?

• It goes between the tibia & fibula during DF → causes them to separate

• MOI for high ankle sprain

What is the name of the lateral tubercle of the talus when it is not united with the rest of the talus?

Os trigonum

What structures articulate in the talocrural joint?

• Tibia + fibula

• Talus

What type of joitn is the distal tib/fib?

Fibrous syndesmosis joint

Which ligaments hold the distal tib/fib joint together?

• Anterior tibiofibular ligament

• Interosseous tibiofibular ligament

• Posterior tibiofibular ligament

What is the clinical application for distal tib/fib joint?

• Area of high ankle sprains

• MOI: DF brings wide anterior talus b/w tibia & fibula → separate them

What type of joint is the talocrural joint?

Synovial hinge joint

What structures articulate in the talocrural joint?

• Talus

• Mortise (formed by medial & lateral malleoli)

In what direction is the talocrural joint’s capsule the weakest?

Anteriorly → allows lots of PF

What are the motions of the talocrural joint?

DF & PF

Name the lateral ankle ligaments

• Anterior talofibular (ATFL)

• Posterior talofibular (PTFL)

• Calcaneofibular (CFL)

Name the medial ankle ligaments that make the deltoid ligament.

• Anterior tibiotalar

• Posterior tibiotalar

• Tibionavicular

• Tibiocalcaneal

What is the blood supply to the talocrural joint?

Malleolar branches of anterior tibial, fibular, and posterior tibial arteries

Which nerves supply the talocrural joint?

• Tibial

• Deep fibular

What is the 2nd most common MSK injury?

Ankle sprains

What is the MOI of a high ankle sprain and which joint is impacted?

• DF & eversion

• Distal tib/fib joint

What is the MOI of a lateral ankle sprain and which structures are impacted?

• Inversion & PF

• ATFL, PTFL, CFL

What is the MOI of a medial ankle sprain and which structures are impacted?

• Eversion

• Deltoid ligament (anterior/posterior tibiotalar, tibionavicular, tibiocalcaneal)

Which ankle sprain is treated most conservatively?

High ankle sprain

Why is a medial ankle sprain way less common than the other sprains?

• Strong deltoid ligament

• Lateral malleolus acts as bony block

Which ankle sprain is the most common?

Lateral ankle sprain

Which bones can experience avulsion fractures from ankle sprains?

• Malleoli

• Base of 5th met

What structures attach to the sustentaculum tali?

• Tibiocalcaneal ligament

• Spring ligament

• Tibialis posterior

Which is the largest and strongest tarsal bone?

Calcaneus

Which bones articulate for the subtalar joint?

Talus + calcaneus

What is the function of the calcaneus?

Transmit most of weight experienced by talus to the ground

What is the clinical application for the calcaneus?

Falling from or jumping from a height can result in fracture (“romeo’s fracture”)

What type of joint is the subtalar joint?

Plane synovial joint

What are the primary motions of the subtalar joint?

Inversion & eversion

Which ligaments go from the talus to calcaneus to help support and stabilize the subtalar joint?

• Medial talocalcaneal

• Lateral talocalcaneal

• Posterior talocalcaneal

• Interosseous talocalcaneal

Which talocalcaneal ligament is the most important?

Interosseous → very strong

What is the most common cause of bursitis of the subcutaneous bursa of the medial and lateral malleoli?

• Tight fitting boots/shoes

• Ice hockey, figure skating, dancing, military

What are retinacula?

Reinforcements of deep fascia

Which structures are covered by the extensor retinacula?

Extensor tendons (EHL, EDL)

What structures are covered by the flexor retinacula?

• Flexor tendons (FDL, FHL, Tib Post)

• Tibial nerve

• Posterior tibial artery

What structures are covered by the fibular retinaculum?

Tendons of fibularis longus & brevis

What is the clinical application of the fibular retinaculum?

• It’s job is to keep tendons in place

• If it is not doing its job, tendons will roll over lateral malleolus

• VERY PAINFUL

Is the tarsal sinus medial or lateral?

Lateral

Is the tarsal tunnel medial or lateral?

Medial

What is tarsal tunnel syndrome?

Flexor retinaculum compresses tibial nerve