LE weakness

Know where spinal cord ends, and the location of spinal nerve root exiting the spinal cord. 
Appreciate Lesion at T4 vertebrae, nerve damage is likely T5 spinal cord, and even T6


Appreciate anterior division and posterior division of nerve 
Know how Lumbar plexus is formed. 
Know how Sacral Plexus is formed. 
Know how Coccygeal Plexus is formed. 
Know the following are the nerve exiting the pelvic bone down in to the legs
  1. Lateral Cutaneous Nerve of Thigh L2, L3
  2. Sciatic Nerve
    1. Common fibular (Peroneal Nerve) (Posterior Division)
    2. Tibial Nerve (Anterior Division) 
  3. Posterior cutaneous nerve of thigh 
  4. Femoral Nerve 

Appreciate a location to examine for LE sensory examination corresponding to the dermatomes 
  • L1, L2, L3, L4, L5, S1, S2, S4, S4
  • Appreciate the location of S3, S4, S5 sensory distribution 

Appreciate that radiculopathy involving L3, L4, L5 and S1 will have different extent of radiation based on the dermatomal distribution of corresponding nerve
  • S1 radiculopathy will radiate all the way down but is more POSTERIOR and PLANTAR Surface of the feet 
  • L5 radiculopathy will radiate all the way down but is more ANTEROLATERAL LEG and DORSUM of the feet
  • L4 is anterior leg but crosses knee (DOES NOT go to the feet(
  • L3 is anteromedial of the thigh (does not cross the knee)
CONTRAST THIS TO SCIATIC Nerve involvement in any position, where pain will radiate all the way down as it has S1 nerve root. Please see the diagram of the lumbosacral plexus 

Appreciate the involvement of Sacral Nerve root in Cauda Equina and how it will not have sensory or motor loss of the LE. 
Appreciate only area involved is S2, S3, S4 in the perineum 

Appreciate the various location of Nerve Injury and the Mechanism Involved. Few that are worth noting are. 
  • B: 
    • Appreciate how L4-L5 Disc Herniation affects L5 nerve root 
    • Appreciate how annulus fibrosis tear leads to disk herniation by herniation of the nucleus pulposus 
  • C: Spondylolistheis i.e anterior slippage of lumbar vertebrae leads to stretch of nerve roots 
  • D: Appreciate foramina stenosis due to Apophyseal joint hypertrophy and Ligamentous Hypertrophy 
  • E: Appreciate Synovial cyst from apophygeal joint degeneration that causes spinal stenosis 

Appreciate the mechanism of Straight-Leg-Raise Test 
Appreciate how to increase the sensitivity of the test by streching the nerve roots further 

Appreciate how Degenerative Facet-Joint Hypertrophy causes Foraminal Narrowing causing Radiculopathy 

Motor Examination of Lower Limb
Reflex Examination of Lower Limb 

Tests for Lumbo-Sacral Nerves
  1. Tibialis anterior (L5)
  2. Extensor digitorum longus (L5)
  3. Extensor hallucis longus (L5)
  4. Popliteus (L5)
  5. Tibialis posterior (L5)
  6. Peroneus longus (S1)
  7. Peroneus brevis (S1)
  8. Gastrocnemius (S1)
  9. Soleus (S1)
  10. Plantaris (S1)
  11. Flexor digitorum longus (S2)
 Tests for Peripheral Nerves