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Knee, ankle and foot
Muscles and movements
Muscle | Origin | Insertion | Movement | Joint | Misc. Info |
---|---|---|---|---|---|
Vastus medialis | Medial lip of linea aspera, intertrochanteric line | Medial border of patella and tibial tuberosity via patellar ligament | Extension | Anterior knee | Uniarticular muscle of quadriceps femoris; "tear drop" muscle |
Vastus intermedius | Anterior, lateral femur | Patella and tibial tuberosity via patellar ligament (quadriceps tendon) | Extension | Anterior knee | Uniarticular muscle of quadriceps femoris; deep to rectus femoris; weakest quad |
Vastus lateralis | Greater trochanter, gluteal tuberosity, lateral lip of linea aspera, intertrochanteric line | Patella and tibial tuberosity via patellar ligament | Extension | Anterior knee | Uniarticular muscle of quadriceps femoris; role in chondromalacia patella; largest quad |
Biceps femoris (short head) | Linea aspera (distal half) | Apex/head of fibula | Flexion; external rotation (tibia) (unloaded leg) | Posterior knee | Lateral hamstrings; some people don't have, or runs into long head |
Popliteus | Lateral condyle (femur) | Posterior proximal tibia, lateral meniscus | Flexion, medial rotation (tibia) (unloaded leg) | Posterior knee | Unlocks knee |
Gastrocnemius | Posterior distal femur near medial condyle (medial); posterior distal femur near lateral condyle, fabella (lateral); popliteal surface of femur (3rd) | Calcaneus via calcaneal (Achilles') tendon | Flexion (assists); plantarflexion | Posterior knee, posterior ankle | Fabella: sesamoid bone (30% have) |
Plantaris | Lateral supracondylar ridge of femur | Posterior calcaneus (can merge with Achilles') | Flexion (assists); plantarflexion (assists) | Posterior knee, posterior ankle | "Freshman nerve"; surgical grafts; 10% don't have |
Soleus | Posterior proximal tibia, fibula | Calcaneus via calcaneal tendon | Plantarflexion | Posterior ankle (superficial) | With gastrocnemius: "triceps surae"; "peripheral heart"; primary muscle to correct for swaying while standing; lots of type II fibers |
Tibialis posterior | Posterior lateral tibia, posterior medial fibula (not interosseous membrane) | Plantar surface of navicular, cuneiforms and cuboid, bases of metatarsals (2-4), sustentaculumtali | Plantarflexion (assists), inversion | Posterior ankle (deep), subtalar | Attaches to every tarsal and metatarsal except talus and metatarsals 1,5 |
Flexor digitorum longus | Medial posterior tibia | Plantar surfaces of distal phalanges (2-5) via split tendons | Flexion (toes), plantarflexion (assists), inversion | Posterior ankle (deep), subtalar, foot | Passes through split tendons of flexor digitorum brevis; splits like flexor digitorum superficialis (hand); passes behind, superior to sustentaculum tali and medial malleolus (tibia) |
Flexor hallucis longus | Distal posterior fibula, interosseous membrane | Plantar surface of distal phalanx of hallux | Flexion (hallux), plantarflexion (assists) | Posterior ankle (deep), foot | Huge role during gait; large for a deep muscle; crosses inferior to sustentaculum tali; tibialis posterior is slightly superior (more "next to") |
Peroneus longus | Oroximal lateral fibula (2/3), (lateral tibial condyle) | Base of 1st metatarsal, lateral side of medial cuneiform | Plantarflexion (assists), eversion | Lateral ankle, subtalar | Peroneal/fibular muscle: most superficial, biggest, held in by peroneal retinacula; corss outside ankle joint, under foot; fairly weak |
Peroneus brevis | Distal lateral fibula (2/3) | Dorsolateral surface of 5th metatarsal | Plantarflexion (assists), eversion | Lateral ankle, subtalar | Peroneal/fibular muscle: held in by peroneal retinacula |
Peroneus tertius | Distal anterior fibula, interosseous membrane | Dorsal surface of base of 5th metatarsal | Dorsiflexion, eversion | Anterior ankle, subtalar | Peroneal/fibular muscle |
Tibialis anterior | Lateral tibial condyle, interosseous membrane | Plantar surface of medial cuneiform, base of 1st metatarsal | Dorsiflexion, inversion | Anterior ankle, subtalar | Prevents toe dragging; shin splints; most powerful anterior muscle |
Extensor digitorum longus | Lateral tibial condyle, anterior fibula, interosseous membrane | Dorsal surfaces of bases of middle/distal phalanges (2-5) via split tendons | Dorsiflexion (assists), eversion (weak), extension (toes 2-5) | Anterior ankle, subtalar, foot | |
Extensor hallucis longus | Anterior fibula, interosseous membrane | Dorsal surface of distal phalanx of hallux | Dorsiflexion, extension of hallux | Anterior ankle, foot | |
Extensor digitorum brevis | Dorsal calcaneous, inferior band of extensor retinaculum | Extensor digitorum longus tendons (merges) (lateral sides of toes 2-4) | Extension (toes 2-4) | Dorsal foot | Intrinsic muscle of foot; does not insert onto bone |