Back to ELM2: Musculoskeletal
Lower Limb Anatomy & Knee Pathology
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Lesson 2 of 20
Notes
Lower Limb Anatomy & Knee Pathology
Knee Joint Stabilisers
- ACL: prevents anterior tibial translation; resists knee hyperextension
- PCL: prevents posterior tibial translation (strongest ligament in knee)
- MCL: resists valgus stress
- LCL: resists varus stress
- Medial meniscus: C-shaped, less mobile, more commonly torn
- Lateral meniscus: O-shaped, more mobile
Clinical Tests
| Test | Structure tested | Positive finding |
|------|-----------------|------------------|
| Anterior drawer | ACL | Anterior tibial shift >5 mm |
| Lachman | ACL | Soft end-point on anterior draw at 20┬░ flex |
| McMurray | Meniscus | Click/pain on rotation |
| Valgus stress | MCL | Medial opening |
Nerve Supply of Lower Limb
- Femoral n (L2–4): quadriceps, hip flexors; sensory anteromedial thigh/leg
- Obturator n (L2–4): adductors; sensory medial thigh
- Sciatic n (L4–S3): divides to common peroneal + tibial
- Common peroneal: foot drop if injured (fibular neck)
- Tibial: plantarflexion, intrinsic foot muscles
Compartment Syndrome
- 6 Ps: Pain (out of proportion), Pressure (tight compartment), Paraesthesia, Paralysis, Pallor, Pulselessness
- Commonest compartment: anterior leg (tibialis anterior + extensor hallucis longus)
- Treatment: emergency fasciotomy