OCC OCC Neurological Assessment & Neuromuscular Medicine 1 — Questions and Answers
Question 1: Which cranial nerve carries the afferent limb of the corneal reflex?
- CN III (oculomotor)
- CN V ophthalmic branch (V1) (Correct answer)
- CN VII (facial)
- CN VIII (vestibulocochlear)
Correct answer: CN V ophthalmic branch (V1)
The ophthalmic branch (V1) of the trigeminal nerve (CN V) carries sensory input from the cornea, forming the afferent limb of the corneal reflex.
Question 2: A patient presents with muscle weakness, hyporeflexia, and fasciculations. These findings are most consistent with:
- Upper motor neuron lesion
- Lower motor neuron lesion (Correct answer)
- Cerebellar dysfunction
- Basal ganglia disorder
Correct answer: Lower motor neuron lesion
Lower motor neuron lesions classically produce weakness, hyporeflexia or areflexia, muscle atrophy, and fasciculations due to denervation.
Question 3: In osteopathic medicine, somatic dysfunction at the OA-AA complex (C0-C2) can most directly compromise which cranial nerve function via the jugular foramen?
- CN III (oculomotor)
- CN VI (abducens)
- CN X (vagus) (Correct answer)
- CN XII (hypoglossal)
Correct answer: CN X (vagus)
The vagus nerve (CN X) exits the skull through the jugular foramen, which can be mechanically influenced by somatic dysfunction at the upper cervical region.
Question 4: Which dermatome covers the lateral forearm, thumb, and index finger?
- C5
- C6 (Correct answer)
- C7
- C8
Correct answer: C6
The C6 dermatome supplies the lateral forearm, thumb, and index finger, and is commonly tested in carpal tunnel syndrome evaluation.
Question 5: On MRI, multiple sclerosis most characteristically shows lesions in which location?
- Gray matter cortical lesions
- Periventricular white matter plaques (Correct answer)
- Basal ganglia calcifications
- Diffuse cortical atrophy
Correct answer: Periventricular white matter plaques
MS causes demyelinating plaques predominantly in periventricular white matter, the corpus callosum, and cerebellum, best seen on T2/FLAIR MRI sequences.
Question 6: A positive Babinski sign (upgoing plantar response) indicates a lesion of which neural pathway?
- Spinothalamic tract
- Dorsal columns
- Corticospinal (pyramidal) tract (Correct answer)
- Spinocerebellar tract
Correct answer: Corticospinal (pyramidal) tract
The Babinski sign is a classic upper motor neuron sign indicating disruption of the corticospinal tract, releasing primitive reflexes normally suppressed by descending inhibition.
Question 7: According to osteopathic neurological theory, a 'facilitated segment' is characterized by:
- Spinal cord hyperreactivity due to sustained afferent input lowering the firing threshold (Correct answer)
- Permanent sympathetic inhibition at the affected spinal level
- Motor neuron refractoriness to stimulation following injury
- Nociceptive signals bypassing the spinal cord via direct thalamic pathways
Correct answer: Spinal cord hyperreactivity due to sustained afferent input lowering the firing threshold
A facilitated segment is a spinal cord level with a lowered neural firing threshold caused by sustained afferent input, making it hyperreactive to all stimuli.
OCC OCC Neurological Assessment & Neuromuscular Medicine 1
Which cranial nerve carries the afferent limb of the corneal reflex?