NBCE Neurology and Neurological Assessment 1 — Questions and Answers
Question 1: Which nerve roots mediate the patellar (knee jerk) reflex?
- L2
- L3-L4 (Correct answer)
- L5
- S1
Correct answer: L3-L4
The patellar reflex tests the L3-L4 nerve roots via the femoral nerve and the quadriceps muscle.
Question 2: The C6 dermatome primarily covers which anatomical area?
- The middle finger and central palm
- The thumb, index finger, and lateral forearm (Correct answer)
- The ring and little fingers
- The entire dorsal hand
Correct answer: The thumb, index finger, and lateral forearm
The C6 dermatome supplies the thumb, index finger, and lateral forearm, making it the key level affected by C5-C6 disc herniations.
Question 3: The Achilles tendon reflex (ankle jerk) primarily tests which nerve root?
- L4
- L5
- S1 (Correct answer)
- S2
Correct answer: S1
The Achilles reflex is mediated by S1 via the tibial nerve and tests the gastrocnemius-soleus complex.
Question 4: An upper motor neuron (UMN) lesion characteristically produces which clinical finding?
- Hyporeflexia and fasciculations
- Flaccid paralysis with muscle atrophy
- Hyperreflexia and spasticity (Correct answer)
- Loss of deep tendon reflexes
Correct answer: Hyperreflexia and spasticity
UMN lesions produce hyperreflexia, spasticity, and a positive Babinski sign due to loss of descending cortical inhibition on spinal reflex arcs.
Question 5: Weakness in great toe extension (extensor hallucis longus) is most indicative of which nerve root compression?
- L3
- L4
- L5 (Correct answer)
- S1
Correct answer: L5
The extensor hallucis longus is primarily innervated by L5 via the deep peroneal nerve, making great toe extension weakness the classic L5 myotomal test.
Question 6: A positive Brudzinski sign is a clinical indicator of which condition?
- Lumbar disc herniation
- Meningeal irritation (Correct answer)
- Cerebellar dysfunction
- Brachial plexus injury
Correct answer: Meningeal irritation
Brudzinski sign is positive when passive neck flexion causes involuntary hip and knee flexion, indicating meningeal irritation as seen in meningitis or subarachnoid hemorrhage.
Question 7: Which dermatome covers the lateral thigh region?
- L1
- L2 (Correct answer)
- L3
- L4
Correct answer: L2
The L2 dermatome covers the anterior and lateral thigh, and is supplied by the lateral femoral cutaneous and femoral nerves.
NBCE Neurology and Neurological Assessment 1
Which nerve roots mediate the patellar (knee jerk) reflex?