Lower-Limb Muscle Anatomy – Foot & Leg (O/I/N/A)

14 vocabulary flashcards summarizing origin, insertion, innervation, and primary actions of key foot and lower-leg muscles discussed in the lecture notes.

Flexor Hallucis Brevis

Origin: plantar cuboid & lateral cuneiform; Insertion: both sides of base of proximal phalanx of great toe; Innervation: medial plantar n. (L5–S1); Action: flexes great toe at proximal phalanx

Flexor Hallucis Longus

Origin: lower posterior fibula; Insertion: plantar base of distal phalanx of great toe; Innervation: tibial n. (S1–S2); Action: powerful flexion of hallux

Flexor Digitorum Brevis

Origin: medial tubercle of calcaneus & plantar aponeurosis; Insertion: both sides of middle phalanges 2–5; Innervation: medial plantar n. (L5–S1); Action: flexes digits 2–5 at MTP & PIP joints

Flexor Digitorum Longus

Origin: medial posterior tibia; Insertion: plantar bases of distal phalanges 2–5; Innervation: tibial n. (L4–S3); Action: flexes digits 2–5, plantar-flexes & inverts foot

Extensor Hallucis Brevis

Origin: calcaneus & inferior extensor retinaculum; Insertion: dorsal base of proximal phalanx of great toe; Innervation: deep fibular n. (L5–S1); Action: assists EHL in extending great toe at MTP

Extensor Hallucis Longus

Origin: anteromedial fibula; Insertion: dorsal base of distal phalanx of great toe; Innervation: deep fibular n. (L5–S1); Action: extends hallux at all joints

Extensor Digitorum Brevis

Origin: upper-lateral calcaneus & related ligaments; Insertion: tendons to bases of proximal phalanges 2–4; Innervation: deep fibular n.; Action: extends toes 2–4, aids longus muscles

Extensor Digitorum Longus

Origin: lateral tibial condyle, superior ¾ medial fibula, interosseous membrane; Insertion: middle & distal phalanges 2–5; Innervation: deep fibular n. (L5–S1); Action: extends toes 2–5, dorsiflexes ankle

Tibialis Anterior

Origin: lateral condyle & superior half of lateral tibia, interosseous membrane; Insertion: medial plantar surface of medial cuneiform & base of 1st metatarsal; Innervation: deep fibular n. (L4–L5); Action: dorsiflexes ankle, inverts subtalar joint

Tibialis Posterior

Origin: posterior tibia below soleal line & posterior fibula; Insertion: navicular, cuneiforms, cuboid, sustentaculum tali, bases of metatarsals 2–4; Innervation: tibial n. (L4–L5); Action: plantar-flexes, inverts, supports medial arch

Peroneus (Fibularis) Longus

Origin: proximal two-thirds lateral fibula; Insertion: medial cuneiform & base of 1st metatarsal (plantar); Innervation: superficial fibular n.; Action: plantar-flexes & everts foot

Peroneus (Fibularis) Brevis

Origin: inferior two-thirds lateral fibula; Insertion: dorsal tuberosity of 5th metatarsal base; Innervation: superficial fibular n. (L5–S2); Action: everts foot, weak plantar-flexor

Gastrocnemius

Origin: lateral head – lateral femoral condyle; medial head – popliteal surface above medial condyle; Insertion: posterior calcaneus via calcaneal tendon; Innervation: tibial n. (S1–S2); Action: plantar-flexes ankle (knee extended), raises heel, flexes knee

Soleus

Origin: posterior head & upper fibula, soleal line & middle medial tibia, tendinous arch; Insertion: posterior calcaneus via calcaneal tendon; Innervation: tibial n. (L5–S2); Action: plantar-flexes ankle regardless of knee position, stabilizes ankle