Lecture 10 - Biomechanics of the Ankle and Foot (part 1) Flashcards
What are the 5 parts of the ankle/foot?
- tibia
- fibula
- 7 tarsal bones
- 5 metatarsal bones
- 14 palanges
Which portion of the tibia is laterally rotated in the transverse plane with respect to the proximal end of the tibia?
the distal portion
What does the distal portion of the tibia create?
a normal lateral, or external tibial torsion
What does the lateral torsion of the tibia move?
the medial malleolus anteriorly
How does tibial torsion change throughout development?
- Begin in slight lateral torsion or even medial torsion at birth
- Gradually progress to 20-40°of lateral torsion by adulthood
What is tibial torsion measured by?
the angle between aline through the tibial plateaus and aline through the medial and lateral malleoli
What does the fibular participate in?
ankle articulation
What are the 3 parts of the fibula?
head, shaft and lateral malleolus
What does the anterior shaft of the fibula give rise to?
extensor muscles of the foot
What does the lateral surface of the fibula provide attachment to?
peroneal muscles
What does the posterior surface of the fibula provide attachment to?
soleus and flexor hallucis longus
Why is the plane of the articular surface of the lateral malleolus oriented laterally and inferiorly?
so that some of the load through the ankle can be shared by the fibula
Which bone joins the foot to the leg?
the talus
Are there any direct muscle attachments on the talus?
no
What covers more than half of the talus’ surface?
articular cartilage
What is the movement of the talus governed by?
forces applied to it by tibia, fibula and calcaneus
What is the largest tarsal bone?
calcaneus
What are the 3 functions of the calcaneurs?
- Sustains large impact forces during locomotion
- Provides along moment arm for Achilles tendon
- Transmits weight of the body from hind foot to forefoot
What is the structural organization of the foot?
hindfoot, midfoot and forefood
What does the hindfoot consist of?
talus and calcaneus
What does the midfoot consist of?
the remaining tarsal bones
What does the forefood consist of?
metatarsals and phalanges
What are the 3 divisions of the forefoot?
first ray, second and third rays, fourth and fifth rays
What comprises the first ray?
metatarsal of the big toe and the medial cuneiform bone
What comprises the second and third rays?
second and third metatarsals and their proximal cuneiform bones
What comprises the fourth and fifth rays?
fourth and fifth metatarsals
