The Leg, Ankle and Foot Flashcards
What are the bones of the leg?
Tibia and fibula
What are the tibia and fibula connected by?
A tough, fibrous intraosseous membrane
What are the elongated projections from the distal tibia and fibula?
The melleli (lateral and medial)
What do the malleoli form?
Together form a socket (‘mortise’) for the talus
What forms the ankle joint?
The articulation between the malleoli and the talus
What type of joint is the ankle jiont?
A talocrural joint
What is the talocrural joint?
A synovial hinge joint that connects the distal ends of the tibia and fibula in the lower limb with the proximal end of the talus
What 3 bones form the ankle joint?
- Distal tibia
- Distal fibula
- Talus
Anterior view of tibia and fibula
What is highlighted in orange?
Lateral and medial malleolus
What is highlighted in green?
Talus
What is highlighted in yellow?
Ankle mortise
What is highlighted in black
Sharp anterior border of tibia
What is higlighted in green?
Tibial plateaus
What is highlighted in purple
Soleal line
What is highlighted in green and orange?
Green - tallus
Orange - lateral malleolus
What movements are possible at the ankle joint?
- Extension / ‘dorsiflexion’
- Flexion / ‘plantarflexion’
- Inversion
- Eversion
What joint does inversion and eversion happen at?
The subtalar joint
What is the subtalar joint?
An articulation between two of the tarsal bones in the foot – the talus and calcaneus
What type of joint is the ankle joint?
A hinge joint
Why is the ankle a very stable joint?
- Good congruity
- Very strong ligaments
When is the ankle joint most stable?
In dorsiflexion / extension:
- The trochlea of the talus is wider anteriorly than posteriorly
- During dorsiflexion, the anterior part of the trochlea moves between the malleoli
- This spreads the tibia and fibula slightly, increasing their grip on the talus
What makes up the lateral ligaments of the ankle?
The lateral ligament complex is comprised of several ligaments on the lateral aspect of the ankle that help to stabilise. These are:
- Posterior talofibular ligament
- Calcaneofibular ligament
- Anterior talofibular ligament
What is the medial ligament complex often referred to as? Why?
The deltoid ligament - due to its resemblence to the Greek letter deltoid
What is the medial ligament complex?
Made up of lots of ligaments that form this deltoid/medial ligament complex
What is the medial ligament attached to?
The medial malleolus and fans out to attach to the talus, navicular and calcaneus
What joints are found in the foot?
Synovial joints
What is the foot equivalent of carpal bones?
Tarsal bones
What is the foot equivalent of metacarpals?
Metatarsals
What is the foot equivalent of phalanges?
Phalanges:
- The big two has 2 phalanges just like the thumb
- Toes 2-5 have 3 phalanges, like fingers 2-5
What bone is highlighted? What articulation is this involved in?
The talus - involved in ankle articulation
What is highlighted in pink?
The calcaneum - the ‘heel’ bone
What bone is highlighted in blue?
The navicular - found on medial aspect of foot
What is highlighted in orange?
Set of 3 bones called the cuneiforms (medial, intermediate and lateral)
What is highlighted in green?
The cuboid bone
What is highlighted in yellow?
Metatarsals
What do the metatarsals articulate with distally? What joint is this?
The phalanges - at the metatarsophalangeal joint (MTP joint)
What are the joints between the phalanges called?
Interphalangeal joints (just like in the hand)
Why is the foot functionally crucial?
- Support and transmits body weight
- Acts as a lever to propel body forward during motion (especially big toe)
- Acts as a resilient spring to absorb shock
- Series of small bones and ligaments can deform to absorb shock and adapt to uneven surfaces - if the foot was RIGID each impact with the ground would generate large forces
What are the movements at the toes?
Flexion, extension, adduction, abduction
What joint in the foot is especially important in locomotion?
Flexion at the 1st metatarsophalangeal joint
At what joints in the foot is flexion and extension possible?
MTPJs, PIPJs, DIPJs and the IPJ of the big toe
At what joints in the foot is abduction and adduction possible?
Limited abduction and adduction at the MTPJs
What are movements of the toes brought about by?
- Extrinsic muscles (muscles in the leg)
- Intrinsic muscles (muscles in the foot)
What are the 3 bony arches of the foot?
- Lateral longitudinal (LLA)
- Medial longitudinal (MLA)
- Transverse (TA)
How do the 3 bony arches of the foot help to increase stability?
- Distribute weight
- Absorb shock
- Increase flexibility
What movements are the 3 bony arches of the foot involved in?
Act as springboards for propulsion during walking, running and jumping
How are the arches of the foot maintained?
The arches are maintained by passive supports (ligaments, shape of the bones) and dynamic supports (the intrinsic and extrinsic muscles of the foot)
What are the compartments of muscles in the leg?
N.B. ‘leg’ refers to lower leg NOT thigh
- Anterior
- Posterior
- Lateral
What are the compartments of the leg separated by?
Fascial septae and enclosed by a fibrous sleeve called the deep fascia of the leg
What is compartment syndrome?
A painful condition that occurs when pressure within the muscles builds to dangerous levels. This is caused by:
- Swelling or bleeding inside compartments
- Fascia doesn’t stretch
- So muscles and nerves and vessels are compressed
How many muscles form the anterior compartment of the legs? What are they?
3:
- Tibialis anterior
- Extensor digitorum longus
- Extensor hallucis longus
What is the collective action of the anterior compartment of the leg?
Collectively, they act to dorsiflex and invert the foot at the ankle joint. The extensor digitorum longus and extensor hallucis longus also extend the toes.
What are the muscles of the anterior compartment innervated by?
The deep fibular nerve (branch of the common fibular)
What are the roots of the deep fibular nerve?
L4-S1
What is the blood supply of the anterior compartment of the leg?
The anterior tibial artery