Ankle and Foot Biomechanics
neutral position of the foot
0 degrees at the talocrural joint the foot is 90 degrees to the leg
Os Trigonum
Accessory bone near the posterior lateral talus that can cause painful impingement during plantarflexion
Medial Lateral Axis of Rotation
Axis of rotation for the talocrural joint
Longitudinal Axis
Axis of rotation for transverse tarsal joint
Oblique Axis
Axis of rotation for transverse tarsal joint
Arch
Curved structure of the foot
Plantarflexion
Downward movement of the foot away from the shin
Pronation
Eversion and abduction of the foot
Pronation during Gait
Foot movement involving arch lowering and internal rotation of tibia/fibula
Supination during Gait
Foot movement involving arch raising and external rotation of tibia/fibula
Lateral Ankle Sprains
Injury caused by forceful inversion of the ankle two-thirds of all inversion sprains involve combined calcaneofibular and anterior talofibular injury
Supination
Inversion and adduction of the foot
Inversion
Inward movement of the foot - 25-30 degrees
Subtalar Joint
Joint between the talus and calcaneus
Transverse Tarsal Joint
Joint between the talus and navicular/cuboid
Gait
Manner of walking
Osteokinematics of the Talocrural Joint
Motion of the talus and tibia/fibula at the ankle joint
Eversion
Outward movement of the foot- 5-15 degrees
Stance Phase
Phase of gait when the foot is in contact with the ground
Osteokinematics
Study of joint motion
Dorsiflexion
Upward movement of the foot towards the shin
talocrural joint
a joint in the ankle found between the tibia, fibula, and talus with one degree of freedom around slightly oblique medial lateral axis of rotation
talocrural joint ROM
dorsiflexion (10-20 degrees) associated with slight abduction and eversion plantarflextion (40-55 degrees) associated with slight adduction and inversion
weight-bearing kinematics
pronation and supination occur as leg and talus (together) rotate over fixed calcaneus
Non-weight-Bearing kinematics or open chain
pronation and supination occur by calcaneus moving on fixed talus
arthrokinematics of the talocrural joint during dorsiflexion
talus slide posterior, calcaneofibular ligament becomes taut
arthrokinematics of the talocrural joint during plantarflexion
talus slides anterior, anterior talofibular ligament and deltoid ligament are taut in plantarflexion
