Leg and Foot

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).

⭐ 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).

⭐ 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.

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.