Lecture 4 - The Ankle and the Foot Flashcards
What is the basic structure and function of the foot?
Complex structure of 26 bones
Load bearing
Locomotion
Shock absorption and a lever for propulsion
What is the longitudinal arch?
Formed by the calcaneus, talus, navicular, cuneiforms / cuboid and metatarsals
Can be high medium or low
Known for shock absorption
What is the transverse arch?
Extends across the foot from the 1st to 5th metatarsals
Weight bearing on uneven surfaces
What is Pes planus?
Flat feet
Low arches - softer foot type, good shock absorption, less propulsion may be due to excessive eversion
What is Pes cavus?
High arch
Rigid, poor shock absorption, good propulsion
What is the plantar fascia?
A web like ligamentous structure
Attached to the calcaneus, metatarsals, phalanges and the skin
Helps support the base of the entire foot including both arches during load bearing
What is the plantar fasciitis?
Inflammation of the plantar fascia
Over use injury
What are the joints of the foot and ankle?
Talocrural joint - ankle
Subtalar joint
Transverse tarsal joint
Tarsometatarsal joint
Metatarsophalangeal joint
Interphalangeal joint - some digits we have 2 but the hallux has 1
What is the talocrural joint?
Between the tibia, fibula and talus
Hinge - uniaxial
Only 40 - 50 degrees plantarflexion and 15-20 degrees of dorsiflexion
Mortise
What is the subtalar joint?
Under the talus
Gliding joint between talus and calcaneus
What is the transverse tarsal joint?
Talus, calcaneus, cuboid, navicular
Gliding joint
Movements allow inversion and eversion and as a result pronation and supination
What are the 4 compartments?
Superficial posterior
Deep posterior
Anterior
Lateral
What are the muscles of the superficial posterior compartment?
Gastrocnemius - origin - posterior of femoral condyles insertion - calcaneus
Soleus - origin - posterior of the proximal fibula and tibia insertion - calcaneus
Plantar flexors
What are the muscles of the deep posterior?
Tibialis posterior
origin - Interosseus membrane
insertion - Navicular cuneiforms and base of metatarsal 2,3,4,5
Assists with plantar flexion and inversion
Flexor digitorum longus - toe flexion
Origin - middle third of posterior surface of tibia
Insertion - Base of distal phalanx of 4 toes
Flexor Hallucis Longus
Origin - Middle 2/3 of posterior surface of fibula
Insertion - Base of distal phalanx of large toe
What are the muscles of the anterior compartment?
Tibialis anterior - Inserts on the medial foot 1st metatarsal
Extensor Hallucis longus origin - middle 2/3 of the fibula
Extensor digitorum longus - head of the tibia
Primary dorsiflexors
What are the muscles of the lateral compartment?
Peroneus longus
Peroneus brevis
Peroneus tertius
Primary evertors
Longus and brevis plantarflexion
Tertius dorsiflexion
Outline an Achilles tendon rupture
Symptoms - Sudden onset of sharp pain in heel, a snapping sound, difficult walking
Causes - sudden dorsiflexion when muscle is in tension, sudden heavy activation of Achilles after prolonged periods of inactivity (atrophy)
What are shin splits?
Small tears / inflammation of muscles attaching to the tibia
Stress fractures
What are ankle sprains?
90% caused by inversion
Less common via eversion
Once a sprain has occurred the chance of re-injury increases by 50%
