Session 5: Functional Anatomy of the Foot and Ankle Flashcards
The bones of the foot can be divided into three gross groups. Which? Say how many of each as well.
- Tarsal bones - 7 bones situated proximally
- Metatarsal bones - in between tarsal and phalanges. 5 in total, one for each toe.
- Phalanges - These are the bones of the toe. Each toe has 3 phalanges except for the big toe which only has 2.
What type of bone are the tarsal bones?
Irregular.
The foot can be divided into three regions. Which?
- Hindfoot
- Midfoot
- Forefoot
Which bones can be found in the hind foot?
The talus and calcaneus bones.
Which bones can be found in the mid foot?
The navicular, the cuboid and the cuneiforms bones.
Which bones can be found in the forefoot?
The metatarsals and the phalanges.
Which is the most superior bone of the foot/tarsal bones?
The talus.
What three articulations does the talus have?
Ankle joint between talus trochlear, tibia and fibula superiorly.
Subtalar join between talus and calcaneus inferiorly.
Talonavicular joint between the talus and navicular anteriorly.
What is the main function of the talus?
To transmit forces from the tibia to the calcaneus.
Mention the muscles that insert and originate from the talus.
No muscles insert or originate in the talus.
Why does the talus heal poorly?
Because of avascular necrosis. The blood supply is retrograde which means that it comes from the distal ends of the foot into the talus. It also lacks muscle attachments.
This makes the talus less effective of healing.
Which is the largest tarsal bone? Where can it be found?
The calcaneus which can be found inferior to the talus. (Heel)
What articulations does the calcaneus have?
Subtalar joint also called talocalcaneal joint between the talus and calcaneus superiorly.
Calcaneocuboid joint between the calcaneus and the cuboid which can be found anteriorly.
There is a protrusion posteriorly on the calcaneus. What is it called and what is its function?
It is called calcaneal tuberosity, here the achilles tendon attaches.
The calcaneus takes the full weight of the body when the heel contacts the ground when walking.
What is the proximal row of the tarsal bones?
The calcaneus and the talus.
What is the intermediate row of the tarsal bones?
It consists of only one bone and that is the navicular.
Location, articulation and insertion/origination of the the navicular bone.
Found medially articulating with the talus posteriorly and with all three cuneiform bones anteriorly and the cuboid bone laterally.
On the plantar surface of the navicular there is a tuberosity for the insertion of part of the tibias posterior tendon.
What is the distal row of the tarsal bones?
Four tarsal bones: cuboid, and the lateral, intermediate and medial cuneiforms bones.
Location, articulation and insertion/origination of the cuboid bone.
Furthest lateral.
Articulates proximally with the calcaneus and distally with the fourth and fifth metatarsals.
Plantar surface of the cuboid has a groove for the insertion of tendon of peroneus (fibularis) longus.
Location, articulation and function of the three cuneiforms.
Medial to the cuboid.
Articulates with the navicular proximally and distally with the first, second and third metatarsals.
Wedge shape of the cuneiform bones helps to form the transverse arch of the foot.
How are the metatarsals numbered?
By Roman numerals. I medially and V laterally.
What are the joints between the metatarsals and the tarsal bones called?
Tarsometatarsal joints.
What are the joints between the metatarsals called?
Intermetatarsal joints.
What are the joints between the metatarsal head and the proximal phalanx called?
Metatarsophalangeal joints.
What does each metatarsal consist of?
A base, a shaft, a neck, and a head.
What does each phalanx consist of?
A base, a shaft and a head.
What is the ankle mortise?
A bracket-shaped socket.
How is the ankle mortise formed?
By the tibia and fibula via tibiofibular ligaments at the distal tibiofibular joint.
What bone, and what part of that bone fits into the ankle mortise?
The trochlea of the talus.
What is dorsiflexion and what part of the trochlea of the talus fits into the ankle mortise at dorsiflexion?
Dorsiflexion is when you flex your foot upwards pointing toes at sky.
The anterior part of the trochlea of the talus is in the mortise at this point.
What is plantarflexion and what part of the trochlea of the talus fits into the ankle mortise at plantarflexion?
Plantarflexion is when you flex your foot downwards pointing toes at ground.
The posterior part of the trochlea of the talus is in the mortise at this point.
What are the movements allowed at the ankle joint?
Only dorsi and plantar flexion.
What type of flexion is most stable at the ankle joint and why?
Dorsiflexion is more stable because the anterior part of the trochlea of the talus is larger and that makes it more stable.
Posterior part of the trochlea of the talus is more narrow.
What muscles are involved in plantarflexion?
Posterior part of the leg: gastrocnemius, soles, planters and tibialis posterior.
What muscles are involved in dorsiflexion?
Anterior part of the leg: tibialis anterior, extensor hallucis longus, extensor digitorum longus and peroneus tertius.
The lateral ligament of the ankle has three parts. Which? Which bones do they connect?
Anterior talofibular ligament between lateral malleolus and the neck of the talus.
Posterior talofibular ligament between the malleolar fossa and the lateral tubercle of the talus.
Calcaneofibular ligament between the tip of the lateral malleolus and the lateral surface of the calcaneus.
What is the main function of the lateral ligaments of the ankle?
To resist inversion of the foot.
What are the medial ligaments of the ankle? Which bones do they connect?
There is only one which arches and is called the medial or deltoid ligament. It is stronger and resists excessive eversion of the foot.
From medial malleolus to attach to the talus, calcaneus and the navicular.
Where does inversion and eversion of the foot occur?
NOT at the ankle joint but at the subtalar, calcaneocuboid and the talocalcaneonavicular joints of the mid foot.
Why is inversion and eversion important?
Because it allows us to walk on uneven surfaces.
What type of joint can be found between the talus and calcaneus and what type of joint is it?
The subtalar joint and it is a plane type of synovial joint.
Why is the subtalar joint important?
Because it is the major joint within the foot at which eversion and inversion take place.
What muscles are involved in eversion?
Lateral compartment of the leg: peroneus longus and peroneus brevis.
Anterior compartment of the leg: peroneus tertius.
What muscles are involved in inversion?
Anterior compartment: Tibialis anterior
Posterior compartment: Tibialis posterior