The Foot and Ankle Flashcards
What is the ankle joint formed by?
Articulation between the distal tibia & fibula with the talus.
What type of joint is the ankle joint?
Synovial hinge joint.
What movements does the ankle joint permit? (2)
- Dorsiflexion
- Plantar flexion
What is dorsiflexion?
Pointing the foot upwards.
-dorsum towards shin
What is plantar flexion?
Pointing foot downwards.
-dorsum away from shin
Give 2 example of synovial joint problems that affect the ankle.
- Sepsis
- Rheumatoid arthritis
What helps to stabilise the ankle? (2)
- Good congruity between malleolar mortice and trochlea (talus)
- Very strong ligaments
Where is the trochlea (talus) widest?
Anteriorly.
What is the malleolar mortice?
Rectangular socket formed by the flat surface of the talus and the 2 malleoli (tibia & fibula).
How do the malleolar mortice and the trochlea of the talus help to stabilise the ankle during dorsiflexion?
During dorsiflexion, anterior trochlea moves between malleoli
»spreads tibia and fibula slightly
»increases their grip on talus.
What is the most stable position of the ankle joint?
Dorsiflexion.
What are the lateral ligaments of the ankle? (3)
- Posterior talofibular ligament
- Anterior talofibular ligament
- Calcaneofibular ligament
Which anterior ligament tends to be weaker and what are the consequences?
Anterior talofibular ligament tends to be weaker.
|»_space; sprains
How many medial ligaments are there at the ankle?
One.
-several parts
What are the attachments of the medial ligament?
Attached to the medial malleolus, then fans out»_space; talus, navicular and calcaneus.
What is the medial ligament also called?
Deltoid ligament.
What other structures help to stabilise the ankle? (2)
- Distal interosseous membrane
- Anterior & posterior tibiofibular ligaments
What movements are possible at the ankle? (4)
- Dorsiflexion
- Plantar flexion
- Inversion
- Eversion
What angle does dorsiflexion occur to?
45*.
What muscles are involved in dorsiflexion?
Anterior compartment of the leg.
Which nerve supplies the anterior compartment of the leg?
Deep fibular (peroneal) nerve.
Which artery supplies the anterior compartment of the leg?
Anterior tibial artery.
What angle does plantar flexion occur to?
20*.
What muscles are involved in plantar flexion?
Posterior compartment of the leg.
-except popliteus
Which nerve supplies the posterior compartment of the leg?
Tibial nerve.
Which artery supplies the posterior compartment of the leg?
Posterior tibial artery.
What is inversion?
Pointing sole of foot medially.
Which joints are involved in inversion?
Primarily subtalar joint (not ankle).
-some movement in tranverse tarsal joint
Which nerve roots are involved in inversion?
L4 & L5.
What angle does inversion occur to?
30*.
What is eversion?
Pointing sole of foot laterally (outwards).
Which joints are involved in inversion?
SAME AS INVERSION:
Primarily subtalar joint (not ankle).
-some movement in tranverse tarsal joint
Which nerve roots are involved in eversion?
L5 & S1.
What angle does eversion occur to?
20*.
What is the subtalar joint?
Articulation between talus and calcaneus.
What type of injury causes most ankle sprains?
Inversion injuries (sole >> medially). -twisting of a plantar-flexed foot
What area of the foot is strained in an inversion injury?
Strain on lateral foot.
-especially anterior talofibular ligament
Why do ligaments heal relatively slowly?
They are fairly avascular.
What happens when ligaments detach from bone during ankle sprains?
Fibres do not grow back as extensively»_space; healed ligament usually weaker.
What do torn ligaments increase the likeliness of?
Ankle dislocation.
-destabilise the joint
Which ankle ligament is weaker; lateral or medial?
Lateral ligament is weaker.
-especially anterior talofibular part
How should the joint space appear on a normal ankle x-ray?
The joint space should be an even depth all the way round.
Give an example of a condition that can decrease the joint space at the ankle.
Osteoarthritis.
What is a common ankle fracture?
Lateral malleolar fracture (distal fibula).
- ankle stretched laterally
- inversion injury
What is more common; inversion or eversion injuries?
Inversion injuries.
Which ligament is most likely to be damaged by an eversion injury?
Medial (deltoid) ligament.
-medial ankle strained
What structures can be damaged in an eversion injury?
Eversion injuries pull the medial ligament»_space; tearing of medial malleolus.
» talus rotates laterally
» fracture of fibula
What are the main functions of the foot? (3)
- Support body weight
- Lever to propel body
- Shock absorber
What are the main group of bones in the foot? (3)
- Tarsal bones
- Metatarsal bones
- Phalanges
Which bones makes up the tarsal bones?
- PROXIMAL (talus & calcaneus)
- INTERMEDIATE (navicular)
- DISTAL (cubid & cuneiforms)
What are the proximal tarsal bones? (2)
- Talus
- Calcaneus
What is the intermediate tarsal bone?
Navicular.
What are the distal tarsal bones?
- Cuboid
- Cuneiforms
How many cuneiform bones are there?
THREE:
- medial
- intermediate
- lateral
How many metatarsal bones are there?
Five.
How many phalanges are there?
2 on great toe (I).
3 on other toes (II-V).
-prox/mid/dist
What are the main joints in the foot?
PROX»_space; DIST:
- transverse tarsal joint
- naviculo-cuneiform joint
- tarsometatarsal joint
- metatarso-phalangeal joint
- interphalangeal joints
What 2 joints make up the transverse tarsal joint?
- Talonavicular joint
- Calcaneocuboid joint
Which bones are involved in the transverse tarsal joint? (4)
- Talus & navicular
- Calcaneus & cuboid
What helps to stabilise the foot?
Arches.
How do arches help to stabilise the foot?
- Distribute weight
- Increase flexibility
What are the arches in the foot? (3)
- Medial longitudinal arch
- Lateral longitudinal arch
- Transverse arch
What bones does the medial longitudinal arch consist of? (5)
- Calcaneus
- Talus
- Navicular
- 3 Cuneiforms
- Medial 3 metatarsals
Where is weight transmitted in the medial longitudinal arch?
Through the talus to the calcaneus and metatarsal heads.
What bones does the lateral longitudinal arch consist of? (3)
- Calcaneus
- Cuboid
- Lateral 2 metatarsals
Which arch is higher/more important; lateral or medial longitudinal?
Medial longitudinal arch.
What bones does the transverse arch consist of? (3)
- Cuboid
- 3 Cuneiforms
- Bases of 5 metatarsals
Which 2 mechanism support the arches of the foot?
- Passive
- Dynamic
What is involved in passive support of the arches?
Ligaments and the shape of the bones.
What is involved in active support of the arches?
Intrinsic and extrinsic muscles.
What is pes planus?
Flat foot.
-flat longitudinal arch
What are the 2 types of pes planus?
- Flexible (arch is present when not weight bearing)
- Rigid (i.e. fusion of tarsal bones)
Which type of pes planus is more common?
Flexible.
What usually cause flexible pes planus?
Loose/degenerating ligaments.
What can make pes planus worse?
- Gaining weight
- Standing for a long time
What can pes planus lead to?
Displacement of talus (inf/med)
» misalignment of knee
» pain and decreased shock absorption
» lower back pain
How is pes planus treated?
Specialised insoles (orthotics)»_space; support arches.
What movements are possible in the foot?
- Flexion/extension
- Abduction/adduction (limited)
Which joints does flexion/extension of the foot involve?
- Metatarsophalangeal joints
- Interphalangeal joints (prox/dist)
Which joints does abduction/adduction of the foot involve?
Metatarsophalangeal joints.
What is gout and which joint does it typically affect?
Inflammatory arthritis (crystal deposits). -typically affects 1st MTP joint
What effect does arthritis have on joint space?
Decreases joint space.
What is a Lisfranc injury?
Injury of foot where 1+ metatarsal bones are displaced.
- often requires surgery
- often misdiagnosed
