Q1&2: Biomechanics of the Foot & Ankle Flashcards
Five Purposes of the Foot
- Acts as a base of support for upright posture
- Provides mechanism of rotation for tib/fib during stance phase
- Provides flexibility for shock
- Provides flexibility for uneven terrain
- Acts as a lever for push off
Primary foot/ankle motion - Sagittal
Dorsi- & Plantar- flexion
(ankle and chopart joints)
Primary foot/ankle motion - Coronal
Inversion & Eversion
(subtalar joint)
Primary foot/ankle motion - Transverse
Ab- & Ad- duction
(oblique midtarsal joint axis)
Triplanar Foot/Ankle Patterns - Pronation
- Talocrural - Dorsiflexion
- Forefoot - Abduction
- Subtalar - Eversion
Triplanar Foot/Ankle Patterns - Supination
- Talocrural - Plantarflexion
- Forefoot - Adduction
- Subtalar - inversion
Closed Kinetic Chain
Foot on ground (stance)
Open Kinetic Chain
Foot in air (Swing)
Bones in Segmental Divisions (Tarsus)
AKA: rearfoot
Bones: Talus, Calcaneus
Bones in Segmental Divisions (Lesser Tarsus)
AKA: midfoot
Bones: Navicular, Cuboid, Cuneiforms
Bones in Segmental Divisions (Metatarsus)
AKA: forefoot
Bones: Metatarsals, Digits/Phalanges
Medial Column of the Foot
Most effective at attenuating shock (70%)
Talus, Navicular, Cunieforms, 1-3 Metatarsals
Lateral Column of the Foot
Rigid; enables propulsion
Calcaneus, Cuboid, 4-5 Metatarsals
Vertical Loading through the Shank
Fibula - 17%
Tibia - 83%
Talus
Poor blood supply
No muscle attachment; lots of ligaments
Ariculations:
Anteriorly - navicular
Inferiorly - calcaneus
Calcaneus
Articulations:
Anterior and Posterior facets - Talus
Mechanical advantage is to plantarflex from tendon insertion
Navicular
Distal attachment for tibialis posterior
Clinical Relevance: Feiss line
Cuboid
Articulations:
Proximal - calcaneus
Distal - 4/5th metatarsals
Features the cubital notch/peroneal sulcus (pathway for fibularis tendon)
Talocrural Joint
Motions: Plantar-/Dorsi-flexion
Bones: distal tib/fib and talus
Subtalar Joint
Motions: Inversion & Eversion
Bones: talus and calcaneus
Important for uneven terrain and shock absorption
Oblique Midtarsal Joint Axis
Combo of calcaneo-cuboid and talo-navicular joints
AKA: tranverse tarsal joint; Chopart Joint
Locking/Unlocking the Lateral Column
Rotary movement between proximal cuboid and distal calcaneus. When hindfoot is inverted and OMJA is inverted, the column is “locked” for propulsion
Opposite is true for shock absorption (“unlocked”)
Tarsometatarsal Joint
AKA Lis Franc Joint
Gliding Joint
Bones:
Cuboid -> 4/5th MT
Cuneiforms -> Corresponding MT
Intermetatarsal Joints
Gliding Joint
First ray special test (“Cheesburger Grip”)
Metatarsophalangeal Joints
Condyloid Joint
Movements: Plantar-/Dorsi- flexion; Ab-/Ad- duction (not clinically relevant)
Plantarcalcanealnavicular
Ligament
“Spring Ligament”
Calcaneus to Navicular
Short & Long Plantar Ligament
Calcaneus to Cuboid
Deltoid Ligament
Medial Malleolus to Tarsal bones; maintains medial longitudinal arch and prevents eversions
Plantar Aponeurosis
Medial calcaneus to phalanges
Windlass Mechanism
occurs during the pre-swing phase of gait cycle in which the peak tensile strain and force of the plantar aponeurosis is reached. The increased dorsiflexion angle of the 1st MTP joint is the main causing factor
Fibularis Longus
Attachment: first met and medial cuneiform
Action: Plantarflexes first ray and everts
Innervation: superficial fibular nerve
Active: Initial contact and swing phase
Fibularis brevis
Attachment: fifth met
Action: eversion
Innervation: superficial fibular nerve
Active: Initial contact and swing phase
Triceps Surae (Gastroc-, Soleus, Plantaris)
Attachment: Achilles
Action: Plantarflexion
Innervation: Tibial Nerve
Active: Initial Contact, Toe Off
Tibialis Posterior
Attachment: Navicular, cuneiforms, cuboid
Action: Plantarflexion and Inversion
Innervation: Tibial Nerve
Active: Initial Contact, Toe Off; Stance (inversion)
Flexor Digitorum Longus
Attachment: 2-5 Phalanges
Action: Plantarflexion and Inversion
Innervation: Tibial Nerve
Active: Initial Contact, Toe Off; Stance (inversion)
Flexor Hallucis Longus
Attachment: 1st phalanx of great toe
Action: Plantarflexion and Inversion
Innervation: Tibial Nerve
Active: Initial Contact, Toe Off, Stance (inversion)
Tibialis Anterior
Attachment: medial cuneiform and first met
Action: Dorsiflexion and Inversion
Innervation: Deep Fibular Nerve
Active: Early Stance phase, swing phase
Extensor Digitorum Longus
Attachment: 2-5 phalanges
Action: Dorsiflexion and Inversion
Innervation: Deep Fibular Nerve
Active: Early Stance phase, swing phase
Extensor Hallucis Longus
Attachment: first phalanx
Action: Dorsiflexion and Inversion
Innervation: Deep Fibular Nerve
Active: Early Stance phase, swing phase
Closed Chain Pronation (Hip)
Flexed, Adducted, Internally Rotated
Closed Chain Pronation (Knee)
Flexed, Valgus
Closed Chain Pronation (Ankle)
Dorsiflexed, Tibial internal rotation
Closed Chain Pronation (Subtalar)
Everted
Closed Chain Pronation (Talus)
Plantarflexed, Adducted
Exception to the others
*
Closed Chain Pronation (Oblique Axis)
Dorsiflexed, Abducted
Closed Chain Pronation (Longitudinal Axis)
Everted
Closed Chain Pronation (Medial Longitudinal Arch)
Depressed
Closed Chain Pronation (1st MTP)
Dorsiflexed
(True/False) Closed Chain Supination is the exact opposite compared to pronation.
True
Subtalar Neutral
The foot position that results in congruence of the subtalar, talonavicular, and calcaneocuboid joint at temporal midstance (middle of midstance)
Compensation in the forefoot
The foot/ankle changes hindfoot position to bring the 1st/5th met heads to contact the ground when weightbearing
