Anatomy of Lower Leg, Ankle and Foot Flashcards
What joint is the most frequently injured major joint in the body?
Ankle joint
What is the ankle joint critical in?
Weight bearing and walking
What type of joint is the ankle joint?
Hinge-type uni-axial synovial joint
Where is the ankle joint?
Between the distal part of the tibia and fibula and upper part of the talus
What are the articular surfaces of the ankle joint?
Malleolar mortise with pulley-shaped trochlea of talus
When is malleolar grip strongest?
During dorsiflexion
When is the ankle joint unstable?
During plantar flexion
What is the fibrous capsule of the ankle joint supported by?
Supported on each side by strong collateral ligaments - medial and lateral
What are the features and function of the medial (deltoid) ligament of the ankle joint?
Large strong triangular band
Three slips from the medial malleolus to the talus, calcaneus and navicular
Stabilises the joint during eversion
What are the features of the lateral ligament of the ankle joint?
Has three slips
Weaker than the medial ligament
Commonly involved in ankle injuries
What muscles are responsible for dorsiflexion of the ankle joint?
Tibialis anterior
Extensor digitorum longus
Extensor hallucis longus
Peroneus or fibular tertius
What muscles are responsible for plantarflexion at the ankle joint?
Gastrocnemius
Soleus
Assisted by plantaris, fibialis posterior, flexor hallucis longus and flexor digitorum longus
What kind of injury is an ankle sprain?
Inversion injury
What is a Pott fracture?
Dislocation of the ankle
What causes ‘footballer’s ankle’?
Repeated strain on the anterior capsule
What is tarsal tunnel syndrome?
Tibial nerve compression deep to the flexor retinacula
What are the functions of the foot?
Supports the body in standing and progression
Levers forward in walking, running and jumping
Where does inversion and eversion of the foot occur?
At the subtalar and transverse tarsal joint
What are the investors of the foot?
Tibialis anterior and posterior
What are the evertors of the foot?
Fibularis longus and brevis
What are the features of the arches of the foot?
Bony arches
Flexible - deform with each ground contact
What are the functions of the arches of the foot?
Act as shock absorbers
Distribute weight over the foot
Act as springboards during walking, running and jumping
What is the higher and more important arch?
The medial longitudinal arch is higher and more important than the lateral
Where does the transverse arch run?
From side to side
What is the integrity of the arches of the foot maintained by?
Shape of the united bones Plantar apopneurosis Long and short plantar ligaments Spring ligament Intrinsic muscles of the foot
How are the arches of the foot clinically relevant?
Flat feet - common in children before the age of 3 due to subcutaneous fat, also common in elderly people
Acquired flat feet due to dysfunction of the tibialis posterior
High arched foot is congenital
Why are the accessory bones of the feet clinically relevant?
Common and frequent source of injury
Destabilised by injury/sprain
Os trigonum and accessory navicular are the most troublesome
Os peroneum also commonly a problem
What are the most common tarsal coalitions?
45% talocalcaneal
45% calcaneonavicular
10% other
Causes stiff hindfeet
What should be considered in a patient with ankle arthritis if there is no known trauma and age < 50 years?
Haemochromatosis
What is the mean age of diagnosis of ankle arthritis?
46, compared with mean age of hip arthritis of 51
What forms the Achilles tendon?
Gastrocnemius and soleus tendons
Thickest, strongest and longest tendon in the body
What is cavovarus foot?
Foot which has a high arch and various of the heel/hindfoot
What are the causes of cavovarus foot?
Equinus foot Neurological Congenital e.g. club foot, idiopathic familial Post-traumatic Weakness of intrinsic muscles
What does weakness of the intrinsic muscles of the foot cause?
Clawing of the toes
What causes the plunger effect by proximal phalanges?
Plantarflexion of metatarsals, and over-action of peroneus longus
What causes hindfoot varus?
Weakness of peroneus brevis
What causes equinus foot?
Weakness of tibialis anterior
What does overpull of the tibialis posterior cause?
Adduction of forefoot
What are the clinical manifestations of cavovarus foot?
Clawing of toes and plantarflexion of muscles - plantar callosities and shoe problems
Weakness of peroneus brevis causing hinfoot varus - ankle instability
Weakness of tibialis anterior causing equinus - altered gait
Over-pull of tibialis posterior causing adduction of forefoot - stress fractures of the lateral metatarsals
What are important features of the history of a patient with suspected cavovarus foot?
Progressive Family history Muscle pain or weakness Elevated creatinine kinase Altered sensation
What does the Coleman block test differentiate between?
Forefoot driven hindfoot varus and hindfoot driven varus
How is the Coleman block test carried out?
Patient stands with first ray hanging over the edge of the block
If hindfoot varus corrects then it is compensating for a rigidly plantar flexed first ray
