W6 – The Foot
We have many joints in the foot. The main ones re:
o The Tibiofibular Joint
o The Talocrural Joint – Where the talus meets the tibia and fibula
o The Subtabular and Transverse Tarsal Joints
Made up of:
o 26 bones in each foot
o 19 large muscles (and many small muscles)
o >100 ligaments, tendons, and muscles
Main functions:
o Support and propulsion
Ankle injuries are common
Poor foot mechanics and gait abnormalities are also common (secondary to improper footwear)
o Having poor foot mechanics early in life will lead to foot discomfort/pathology later in life
Foot Bones
Each foot has 26 bones, which collectively form the shape of an arch
Bodyweight is transferred from the tibia to the talus and the calcaneus
o The talus is one of the few bones involved in locomotion that has no muscle attachments
Anterior portion of the talus is wider than the posterior potion – This means the
ankle is more stable in dorsiflexion than plantar flexion
We have 5 midfoot tarsal bones:
o Navicular Bone – Between the talus and 3 cuneiform bones
o Cuboid Bone – Between the calcaneus and the 4th/5th metatarsals
o 3 Cuneiform Bones – Medial, intermediate, and lateral bones
, 5 metatarsals which are distal to the tarsals
5 phalanges (Toes):
o 3 phalanxes in each toe except the 1st toe (it has 2 phalanxes)
o 2 sesamoids beneath the 1st metatarsophalangeal joint
Distal end of the tibia and fibula are enlarged and protrude horizontally and inferiorly
o These bony protrusions (malleoli) serve as a pulley for the tendons of the posterior muscles:
Behind the lateral malleolus – Peroneus (fibularis) brevis/longus tendons muscles
Behind the medial malleolus – Tibialis posterior, flexor digitorum longus, flexor
hallucis longus muscles
During eversion/inversion of these muscles, we have an increased mechanical
advantage
Joints That Make up the Ankle/Foot
Tibiofibular Joint – Where the tibia/fibular joint together
Talocrural Joint (ankle mortise)
Subtabular – Where the calcaneus and talus meet
Talocalcaneonavicular -Where the calcaneus, talus, and navicular bone meet
Calcaneocuboid Joint
Intertarsal Jiont
Tarsometatarsal Joint
Metatarsophalangeal (MP) Joints
Interphalangeal (PIP, IP, or DIP) Joints
Tibiofibular Joint
Is a syndesmotic amphiarthrodial joint
2 joint areas where the fibula and tibia meet:
o Superior Tibiofibular joint (proximal end)
o Inferior tibiofibular joint (distal end) – Becomes sprained occasionally in heavy contact sports
Ligaments and a strong, dense interosseus membrane between tibia and fibular shafts provide
support
Minimal movement is possible at this joint
Talocrural Joint (Ankle Joint)
We have many joints in the foot. The main ones re:
o The Tibiofibular Joint
o The Talocrural Joint – Where the talus meets the tibia and fibula
o The Subtabular and Transverse Tarsal Joints
Made up of:
o 26 bones in each foot
o 19 large muscles (and many small muscles)
o >100 ligaments, tendons, and muscles
Main functions:
o Support and propulsion
Ankle injuries are common
Poor foot mechanics and gait abnormalities are also common (secondary to improper footwear)
o Having poor foot mechanics early in life will lead to foot discomfort/pathology later in life
Foot Bones
Each foot has 26 bones, which collectively form the shape of an arch
Bodyweight is transferred from the tibia to the talus and the calcaneus
o The talus is one of the few bones involved in locomotion that has no muscle attachments
Anterior portion of the talus is wider than the posterior potion – This means the
ankle is more stable in dorsiflexion than plantar flexion
We have 5 midfoot tarsal bones:
o Navicular Bone – Between the talus and 3 cuneiform bones
o Cuboid Bone – Between the calcaneus and the 4th/5th metatarsals
o 3 Cuneiform Bones – Medial, intermediate, and lateral bones
, 5 metatarsals which are distal to the tarsals
5 phalanges (Toes):
o 3 phalanxes in each toe except the 1st toe (it has 2 phalanxes)
o 2 sesamoids beneath the 1st metatarsophalangeal joint
Distal end of the tibia and fibula are enlarged and protrude horizontally and inferiorly
o These bony protrusions (malleoli) serve as a pulley for the tendons of the posterior muscles:
Behind the lateral malleolus – Peroneus (fibularis) brevis/longus tendons muscles
Behind the medial malleolus – Tibialis posterior, flexor digitorum longus, flexor
hallucis longus muscles
During eversion/inversion of these muscles, we have an increased mechanical
advantage
Joints That Make up the Ankle/Foot
Tibiofibular Joint – Where the tibia/fibular joint together
Talocrural Joint (ankle mortise)
Subtabular – Where the calcaneus and talus meet
Talocalcaneonavicular -Where the calcaneus, talus, and navicular bone meet
Calcaneocuboid Joint
Intertarsal Jiont
Tarsometatarsal Joint
Metatarsophalangeal (MP) Joints
Interphalangeal (PIP, IP, or DIP) Joints
Tibiofibular Joint
Is a syndesmotic amphiarthrodial joint
2 joint areas where the fibula and tibia meet:
o Superior Tibiofibular joint (proximal end)
o Inferior tibiofibular joint (distal end) – Becomes sprained occasionally in heavy contact sports
Ligaments and a strong, dense interosseus membrane between tibia and fibular shafts provide
support
Minimal movement is possible at this joint
Talocrural Joint (Ankle Joint)
