Leg and Foot

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Bones & Joints (Leg & Foot) - Foundation Feats

  • Leg Bones:
    • Tibia: Medial, primary weight-bearer; medial malleolus.
    • Fibula: Lateral, for muscle attachment & ankle stability; lateral malleolus.
  • Foot Bones (26 total):
    • Tarsals (7): 📌 Tall Californian Navy Medical Interns Lay Cuties (Talus, Calcaneus, Navicular, Medial, Intermediate, Lateral Cuneiforms, Cuboid).
      • Talus: Keystone of ankle; articulates tibia/fibula.
      • Calcaneus: Heel bone; largest tarsal.
    • Metatarsals (5): I-V (medial to lateral).
    • Phalanges (14): Proximal, Middle, Distal (Hallux: P, D only).
  • Key Joints:
    • Ankle (Talocrural): Tibia + Fibula + Talus. Hinge: Dorsiflexion/Plantarflexion.
    • Subtalar (Talocalcaneal): Talus + Calcaneus. Inversion/Eversion.
    • Midtarsal (Chopart's): Talonavicular & Calcaneocuboid.
    • Tarsometatarsal (Lisfranc's).

⭐ Talus has no direct muscular or tendinous attachments. anatomical view for NEET PG medical students showing labels

Leg Compartments - Muscle Mania

  • Anterior Compartment

    • Muscles: Tibialis anterior, EHL, EDL, Peroneus tertius.
    • Nerve: Deep Peroneal N.
    • Action: Dorsiflexion, Toe extension, Inversion (Tib. Ant).
    • 📌 Mnemonic: "Teachers Hate Extra Dirty Plays, Never!" (TA,EHL,EDL,PT,Deep Peroneal N.)
  • Lateral Compartment

    • Muscles: Peroneus longus & brevis.
    • Nerve: Superficial Peroneal N.
    • Action: Eversion, Weak plantarflexion.
  • Posterior Compartment (Superficial)

    • Muscles: Gastrocnemius, Soleus, Plantaris.
    • Nerve: Tibial N.
    • Action: Plantarflexion; Knee flexion (Gastrocnemius).
    • 📌 Mnemonic: "Go Slow Please" (Gastrocnemius,Soleus,Plantaris).
  • Posterior Compartment (Deep)

    • Muscles: Tibialis posterior, FDL, FHL, Popliteus.
    • Nerve: Tibial N.
    • Action: Plantarflexion, Toe flexion, Inversion (Tib. Post), Unlocks knee (Popliteus).
    • 📌 Mnemonic: "Tiny Dogs Hate People" (TP,FDL,FHL,Popliteus).

Cross-section of the leg showing muscle compartments

⭐ Anterior compartment is most prone to compartment syndrome.

Foot Anatomy (Muscles & Arches) - Arch & Action

  • Arches of the Foot: Provide shock absorption, weight distribution, propulsion.
    • Medial Longitudinal Arch (MLA): Higher & more dynamic.
      • Bones: Calcaneus, talus, navicular, 3 cuneiforms, medial 3 metatarsals.
      • Keystone: Head of Talus.
      • Dynamic Support: Tibialis posterior (main), FHL, FDL, Tibialis anterior.
      • Static Support: Plantar aponeurosis, spring ligament (plantar calcaneonavicular).
    • Lateral Longitudinal Arch (LLA): Flatter & more rigid.
      • Bones: Calcaneus, cuboid, lateral 2 metatarsals.
      • Keystone: Cuboid.
      • Dynamic Support: Peroneus longus & brevis, Peroneus tertius.
      • Static Support: Long & short plantar ligaments.
    • Transverse Arch: Formed by cuneiforms, cuboid, & metatarsal bases.
      • Keystone: Intermediate cuneiform.
      • Dynamic Support: Peroneus longus, Tibialis posterior, Adductor hallucis (transverse head). Bones of the Foot: Superior, Medial, and Lateral Views

⭐ The tendon of Tibialis Posterior is the primary dynamic support for the medial longitudinal arch of the foot, crucial for maintaining its integrity during weight-bearing activities like walking and running.

Leg & Foot Neurovascular + Clinicals - Nerve Nets & Nasty Knocks

  • Arteries: Popliteal → Ant. Tibial (→ Dorsalis Pedis) & Post. Tibial (→ Medial/Lateral Plantar, Peroneal).
  • Nerves:
  • Clinicals:
    • CPN Injury (Fibular neck): Foot drop (↓DF/EV).

      ⭐ Injury to the Common Peroneal Nerve results in foot drop (inability to dorsiflex and evert the foot).

    • Tibial N. Injury: ↓PF/IV; Tarsal Tunnel Syndrome.
    • Compartment Syndrome (Ant. most common): ↑pressure; 5 Ps (Pain, Pallor, Paresthesia, Pulselessness, Paralysis - late).
    • Achilles Rupture: (+) Thompson test. Foot Drop and Peroneal Nerve Injury

High‑Yield Points - ⚡ Biggest Takeaways

  • Common peroneal nerve injury at fibular neck causes foot drop and sensory loss on foot dorsum.
  • Tibial nerve supplies posterior leg compartment and plantar muscles; injury impairs plantarflexion.
  • Anterior talofibular ligament (ATFL) is most commonly injured in inversion ankle sprains.
  • Medial longitudinal arch is critically supported by the tibialis posterior tendon.
  • Anterior compartment syndrome is most frequent, with severe pain and paresthesia as early signs.
  • Deep peroneal nerve innervates anterior leg muscles, its damage also causing foot drop.

Practice Questions: Leg and Foot

Test your understanding with these related questions

Tibialis posterior is inserted in all of the following bones distally, except for which of the following?

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Flashcards: Leg and Foot

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The _____ nerve (L4-S2 (nerve roots)) provides:- sensory innervation to the dorsum of the foot - motor innervation to the biceps femoris, tibialis anterior, and extensor muscles of the foot.

TAP TO REVEAL ANSWER

The _____ nerve (L4-S2 (nerve roots)) provides:- sensory innervation to the dorsum of the foot - motor innervation to the biceps femoris, tibialis anterior, and extensor muscles of the foot.

common peroneal

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