Foot and ankle

Question 1

How many bones are there in the foot?

Answer 1

26 bones and 2 sesamoid bones

Question 2

Functional requirements of the foot (4)

Answer 2

Withstand high load (body weight)
Adapt to terrain
Be durable
Transfer loads from lower extremity

Question 3

What are the 4 joints in the foot

Answer 3

Subtalar
Midtarsal
Ankle
Metatarsal break

Question 4

What are the articulating bones in the subtalar joints

Answer 4

Calcaneus and Talus

Question 5

What are the articulating bones in the midtarsal joints

Answer 5

Cuboid/Navicular and Calcaneus/talus

Question 6

What are the articulating bones in the ankle joint

Answer 6

Tibia and talus (atypical hinge joint)

Question 7

What foot movement is TIBIAL INTERNAL ROTATION coupled to

Answer 7

Foot eversion

Question 8

What foot movement is TIBIAL EXTERNAL ROTATION coupled to

Answer 8

Foot inversion

Question 9

Factors affecting coupled kinematics in foot

Answer 9

Shape of foot
Magnitude of load (high loads –> less coupling)
Bone loaded (loading the foot vs tibia –> more coupling)

Question 10

What is the consequence of congenital fusion of subtalar joint?

Answer 10

Leads to ball-and socket ankle joint

Question 11

What structural characteristic of the foot allows it to adapt to different terrains (3)

Answer 11

Medial & lateral longitudinal arches
Transverse arches
Plantar fascia

Question 12

What 2 parts of the foot bear the most weight and what proportions

Answer 12

Talus/Calcaneus - 60%

Metatarsals - 30%

Question 13

What 2 movements of the MTP joint characterise Hallux Valgus

Answer 13

Medial of 1st MTP head

Lateral deviation if 1st toe

Question 14

What is the angle above which the toe is classificed as valgus

Answer 14

Greater than 15 degrees

Question 15

Risk factors for Hallux valgus (4)

Answer 15

Female sex
Older age
ligament laxity
Footwear

Question 16

What muscles and ligaments control ab/adduction of the hallux

Answer 16

Adductor hallucis via the lateral collateral ligament

Abductor hallucis via the medial collateral ligament

Question 17

What is the effect on gait (3)

Answer 17

More pressure on hallux
Weight distribution centred more medially - changes moment arm of foot muscles
Eversion of foot

Question 18

Treatment of hallux valgus

Answer 18

Bunionectomy/Exosectomy
Osteotomy
MTP Arthrodesis (fusion)

Question 19

What bone changes are seen in Gout

Answer 19

Osteophytes
Osteolysis
Cartilage damage

Question 20

How does gait change in Gout (2)

Answer 20

Slower walking

Load bearing is more evenly distributed (as opposed to being bore by calcaneus)

Question 21

3 methods of MTP fusion

Answer 21

K wires
Wires
Dorsal locking plates

Question 22

Effects of MTP fusion (3)

Answer 22

Shorter stride length
Reduced plantarflexion
Increased load on other 4 toes

Question 23

Explain the Windlass mechanism

Answer 23

When hallux is dorsiflexed to prepare for toe-off/propulsion the plantar fascia is stretches
Plantar fascia moves proximally
Reduces distance between calcaneus and metatarsals which raises medial longitudinal arch
Allows foot to act as a rigid lever