Functional anatomy of the foot and ankle

Question 1

What are the 3 groups of bones of the foot and how many are there in each group?

Answer 1

• Tarsal bones (7)
• Metatarsals (5)
• Phalanges (14 (3 for each toe except big toe has only 2))

Question 2

What are the 7 bones of the tarsal bones?

Answer 2

• Talus
• Calcaneus
• Navicular
• Cuboid
• Cuneiforms x3

Question 3

What are the 3 articulations of the talus?

Answer 3

• Ankle joint superiorly (between talus and tibia and fibula)
• Subtalar joint inferiorly (between talus and calcaneus)
• Talonavicular joint anteriorly (between talus and navicular)

Question 4

What is the function of the talus?

Answer 4

Transmit forces from the tibia to the calcaneus

Question 5

Why is there more stability for the ankle in the dorsiflexed position?

Answer 5

Trochlear of talus is wider anteriorly than posteriorly

Question 6

Why is there a high risk of avascular necrosis for a fracture to the talus?

Answer 6

• Retrograde blood supply (distal end)

- Lack of muscle attachment (muscles improve vascularity)

Question 7

What are the 2 articulations of the calcaneus bone?

Answer 7

• Subtalar joint superiorly (between talus and calcaneus)

- Calcaneocuboid joint anteriorly (between calcaneus and cuboid)

Question 8

What is the calcaneal tuberosity?

Answer 8

Posterior protrusion of the calcaneus bone where the achilles tendon attaches

Question 9

Where is the navicular and cuboid positioned?

Answer 9

Navicular = medial side
Cuboid = lateral side

Question 10

What are the joints called between metatarsal bones and tarsal bones?

Answer 10

Tarsometatarsal joints

Question 11

What are the joints called between adjacent metatarsal bones?

Answer 11

Intermetatarsal joints

Question 12

What are the joints called between metatarsal and proximal phalanx?

Answer 12

Metatarsophalangeal joint

Question 13

Describe the ankle joint

Answer 13

• Synovial
• Hinge type
• Articulation between tibia, fibula (mortise) and talus (trochlea)

Question 14

What is a mortise (malleolar fossa)?

Answer 14

Bracket-shaped socket formed by the tibia and fibula

Question 15

What are the only 2 movements at the ankle joint?

Answer 15

Plantarflexion (from posterior compartment)

Dorsiflexion (from anterior compartment)

Question 16

What are the 3 lateral ligaments of the ankle joint and what movement do they resist?

Answer 16

• Anterior talofibular ligament (lateral malleolus and neck of talus)
• Posterior talofibular ligament (malleolar fossa and lateral tubercle of talus)
• Calcaneofibular ligament (Tip of lateral malleolus and lateral surface of calcaneus)

-resists excessive inversion

Question 17

Where does the medial ligament of the ankle joint attach and what movement does it resist?

Answer 17

Medial malleolus to talus, calcaneus and navicular

-resists excessive eversion

Question 18

What is the significance of inversion and eversion of the foot?

Answer 18

To allow walking on uneven surfaces

Question 19

Where does inversion and eversion occur?

Answer 19

Subtalar, calcaneocuboid and talocalcaneonavicular joints

-not at ankle joint

Question 20

What are the 3 arches of the foot?

Answer 20

• Anterior transverse arch
• Medial longitudinal arch
• Lateral longitudinal arch

Question 21

How are the shapes of the arches of the foot maintained?

Answer 21

• Interlocking bones
• Ligaments of the foot
• Intrinsic muscles
• Pull of long tendons of extrinsic muscles