Ankle Anatomy and Biomechanics Flashcards
How many bones are in the ankle and foot?
How many articulations?
28
55
Which joint sustains the greatest load per surface area of any joint in the body?
Ankle joint
What percentage of body weight is places on the ankle joint during walking? running?
120% during walking
275% during running
What part of the ankle/foot joint absorbs the majority of the load? second most?
Rearfoot, followed by metatarsal heads
What are the functions of the foot?
- Act as a support base that provides the necessary stability for upright posture with minimal muscle effort
- Provides a mechanism for rotation of the tibia and fibula during stance
- Provides flexibility to adapt to uneven terrain
- Provides flexibility for absorption of shock
- Acts as a lever during push-off
What type of joint is the tibiofibular joint?
Syndesmosis
What is the resting position of the tibiofibular joint?
Plantarflexion
What is the close-packed position of the tibiofibular joint?
Maximum dorsiflexion
What is the capsular pattern for the tibiofibular joint?
Pain on stress
What are the supporting ligaments of the tibiofibular joint?
- Anterior tibiofibular ligament
- Posterior tibiofibular ligament
- Interosseous ligament
Which joint is the mortise joint?
Talocrural joint
What type of joint is the talocrural joint?
Uniaxial modified hinge joint
What is the talocrural joint designed for?
Stability
What is the resting position of the talocrural joint?
10 degrees plantarflexion
What is the closed-packed position of the talocrural joint?
Maximum dorsiflexion
What is the capsular pattern?
PF, DF
What are the supporting ligaments of the talocrural joint?
Deltoid Ligament
- Tibionavicular
- Tibiocalcaneal
- Posterior tibiotalar
- Anterior tibiotalar
Lateral Collateral
- Anterior talofibular
- Posterior talofibular
- Calcaneofibular
What is another name for the talocalcaneal joint?
Subtalar joint
How many degrees of freedom does the subtalar joint have?
3
What is the resting position of the subtalar joint?
Midway between extremes of ROM
What is the closed-packed position of the subtalar joint?
Supination
What is the capsular pattern of the subtalar joint?
Varus, valgus at rearfoot
What are the supporting ligaments of the subtalar joint?
- Lateral (anterior) talocalcaneal ligament
- Medial (posterior) talocalcaneal ligament
- Cervical ligament
- Interosseous ligament
What are the open chain (talus stable) positions of the subtalar joint?
Supination (PF, inversion, adduction)
Pronation (DF, eversion, abduction)
What are the closed chain (calcaneous stable) positions of the subtalar joint?
Supination (talus abduction, dorsiflexion, calcaneal inversion)
Pronation (talus PF, adduction, calcaneal eversion)
What joints comprise the Transverse tarsal (midtarsal) joint?
- Calcaneocuboid joint
- Talocalcaneonavicular joint (talonavicular)
What is the resting position of the transverse tarsal joint?
Midway between the extremes of ROM
What is the closed-packed position of the transverse tarsal joint?
Supination
What is the capsular pattern of the transverse tarsal joint?
DF, PF, Add, Medial rotation
What is the resting position of the cuneonavicular joint?
Midway between extremes of ROM
What is the close packed position of the cuneonavicular joint?
Supination
What is the capsular pattern of the cuneonavicular joint?
DF, PF, Add, Medial rotation
What is the resting position of the cuboidenavicular joint?
Midway between the extremes of ROM
What is the close packed position of the cuboidenavicular joint?
Supination
What is the resting position of the Intercuneiform joints?
Midway between the extremes of ROM
What is the closed packed position of the intercuneiform joints?
Supination
What is the resting position of the cuneocuboid joint?
Midway between the extremes of ROM
What is the close packed position of the cuneocuboid joint?
Supination
What is the close packed position of the tarsometatarsal joint?
Supination
What is the close packed position of the intermetatarsal joints?
Supination
What is the resting position of the metatarsophalangeal joint?
10 degrees extension
What is the close packed position of the metatarsophalangeal joint?
Full extension
What is the capsular pattern of the metatarsophalangeal joint?
Extension, Flexion
During gait, the 1st MTP dorsiflexes about ____ degrees.
60 degrees
During running, squatting, sports, the 1st MTP dorsiflexes about _____ degrees
90 degrees
What is the resting position of the interphalangeal joint?
Slight flexion
What is the close packed position of the interphalangeal joint?
Full extension
Where does the plantar fascia/aponeurosis originate and insert? What is its role?
Originates from the calcaneous and inserts to the plantar forefoot
- serves a supportive and protective role and is intricately involved with the weight-bearing function of the foot
What are the 4 retinacula? What is their function?
- Superior extensor
- Inferior extensor
- Superiofibular
- Flexor
Function: to tether the tendons as they cross the ankle to enter the foot
What does the superior extensor retinaculum contain?
EDL, EHL, Tib Ant, Fib tertius
What does the inferior extensor retinaculum contain?
Dorsal tendons
What does the superiofibular retinacula contain?
Fibularis longus and brevis tendons
What does the flexor retinaculum contain?
Flexor digitorum longus, FHL, Tib Post, and neurovascular bundle
The arches of the foot support the foot by which 3 mechanisms?
- Osseous relationship of the tarsal and metatarsal bones
- Ligamentous support from the plantar aponeurosis and plantar ligaments
- Muscle support
What are the 3 main arches of the foot?
- Medial longitudinal
- Lateral longitudinal
- Transverse arch
What are the symptoms of talipes equinus?
Limited dorsiflexion and contracture of gastrocsoleus
What are the symptoms of clubfoot?
Congenital deformity and talipes equinovarus
What are subjective functional tests?
- The Ankle Joint Functional Assessment Tool
- The foot function index
What are objective functional tests?
- Weight-bearing assessment
- Single-Leg Stance test
- Star excursion balance test