COMSAE Form 113 Practice Exam:
Version 1 With Questions And
Answers With Rationales/Graded
A+/2026 Update/100% Correct
Section 1: Neuroanatomy & Neurology (Questions 1-15)
1. A 20-year-old female presents to the ED after slipping on ice and hitting her
mouth. Her medial maxillary incisors are fractured, and she is in intense pain.
The nerve most likely conveying this pain sensation is?
• A. Anterior superior alveolar
• B. Infraorbital
• C. Middle superior alveolar
• D. Nasopalatine
Correct Answer: B. Infraorbital
Rationale: The infraorbital nerve (branch of CN V2) provides sensory innervation
to the maxillary incisors, upper gingiva, and midface. The anterior superior
alveolar nerve usually supplies the canines and incisors, but the infraorbital is the
larger trunk conducting this pain centrally .
2. A 25-year-old female presents with headaches, diplopia, and peripheral
vision loss. She reports galactorrhea and amenorrhea. MRI reveals a pituitary
mass. Which secretory cells are causing this?
• A. Corticotrophs
• B. Gonadotrophs
• C. Lactotrophs
• D. Somatotrophs
,Correct Answer: C. Lactotrophs
Rationale: Prolactin-secreting adenomas (lactotrophs) cause hyperprolactinemia,
leading to galactorrhea and amenorrhea. Mass effect on the optic chiasm causes
bitemporal hemianopia (peripheral vision loss) .
3. A 62-year-old man with uncontrolled hypertension has step-wise memory
deterioration and falls. MRI is most likely to show?
• A. Multiple lacunar infarcts in the basal ganglia
• B. A single large MCA infarct
• C. Subarachnoid hemorrhage
• D. Normal study
Correct Answer: A. Multiple lacunar infarcts in the basal ganglia
Rationale: This describes vascular dementia due to small vessel disease.
Hypertension causes lipohyalinosis, leading to multiple lacunar strokes affecting
the basal ganglia and deep white matter .
4. A patient presents with left-sided weakness. The left plantar reflex is
extensor. Protrusion of the tongue deviates to the right. Which sensory deficit
is most likely?
• A. Loss of pain/temp on the right arm/leg
• B. Loss of discriminative touch on the left arm/leg
• C. Loss of pain/temp on the left face
• D. Loss of all modalities on the right side
Correct Answer: B. Loss of discriminative touch on the left arm/leg
Rationale: This is medial medullary syndrome (Dejerine syndrome). It spares
pain/temp (spinothalamic tract is lateral) but hits the medial lemniscus
(contralateral touch/proprioception), corticospinal tract, and CN XII (hypoglossal) .
5. Which nerve root is primarily tested by the brachioradialis reflex?
• A. C5
• B. C6
• C. C7
, • D. C8
Correct Answer: B. C6
Rationale: The brachioradialis muscle is innervated by the radial nerve, primarily
receiving contributions from the C6 nerve root. This is a key clinical localizing
sign .
6. A 52-year-old man drinks wood alcohol (methanol). Fundoscopy shows
retinal congestion and blurred disc edges. What causes the ocular toxicity?
• A. Methanol
• B. Formaldehyde
• C. Formic acid
• D. Ethanol
Correct Answer: C. Formic acid
Rationale: Methanol is metabolized by alcohol dehydrogenase to formaldehyde,
then to formic acid. Formic acid is the toxic metabolite that causes metabolic
acidosis and retinal toxicity (optic neuritis) .
7. A patient presents with acute onset of severe "thunderclap" headache and
nuchal rigidity. Non-contrast CT of the head is normal. What is the next best
step?
• A. Discharge patient with migraine medication
• B. CT Angiography
• C. Lumbar puncture
• D. MRI brain with contrast
Correct Answer: C. Lumbar puncture
Rationale: This presentation suggests subarachnoid hemorrhage. If CT is negative
(high sensitivity but misses ~5-10%), an LP must be performed to look for
xanthochromia or red blood cells in the CSF.
8. A 70-year-old patient has a tremor that is present at rest and decreases with
voluntary movement. This is most suggestive of?
• A. Essential tremor
• B. Parkinson’s disease
Version 1 With Questions And
Answers With Rationales/Graded
A+/2026 Update/100% Correct
Section 1: Neuroanatomy & Neurology (Questions 1-15)
1. A 20-year-old female presents to the ED after slipping on ice and hitting her
mouth. Her medial maxillary incisors are fractured, and she is in intense pain.
The nerve most likely conveying this pain sensation is?
• A. Anterior superior alveolar
• B. Infraorbital
• C. Middle superior alveolar
• D. Nasopalatine
Correct Answer: B. Infraorbital
Rationale: The infraorbital nerve (branch of CN V2) provides sensory innervation
to the maxillary incisors, upper gingiva, and midface. The anterior superior
alveolar nerve usually supplies the canines and incisors, but the infraorbital is the
larger trunk conducting this pain centrally .
2. A 25-year-old female presents with headaches, diplopia, and peripheral
vision loss. She reports galactorrhea and amenorrhea. MRI reveals a pituitary
mass. Which secretory cells are causing this?
• A. Corticotrophs
• B. Gonadotrophs
• C. Lactotrophs
• D. Somatotrophs
,Correct Answer: C. Lactotrophs
Rationale: Prolactin-secreting adenomas (lactotrophs) cause hyperprolactinemia,
leading to galactorrhea and amenorrhea. Mass effect on the optic chiasm causes
bitemporal hemianopia (peripheral vision loss) .
3. A 62-year-old man with uncontrolled hypertension has step-wise memory
deterioration and falls. MRI is most likely to show?
• A. Multiple lacunar infarcts in the basal ganglia
• B. A single large MCA infarct
• C. Subarachnoid hemorrhage
• D. Normal study
Correct Answer: A. Multiple lacunar infarcts in the basal ganglia
Rationale: This describes vascular dementia due to small vessel disease.
Hypertension causes lipohyalinosis, leading to multiple lacunar strokes affecting
the basal ganglia and deep white matter .
4. A patient presents with left-sided weakness. The left plantar reflex is
extensor. Protrusion of the tongue deviates to the right. Which sensory deficit
is most likely?
• A. Loss of pain/temp on the right arm/leg
• B. Loss of discriminative touch on the left arm/leg
• C. Loss of pain/temp on the left face
• D. Loss of all modalities on the right side
Correct Answer: B. Loss of discriminative touch on the left arm/leg
Rationale: This is medial medullary syndrome (Dejerine syndrome). It spares
pain/temp (spinothalamic tract is lateral) but hits the medial lemniscus
(contralateral touch/proprioception), corticospinal tract, and CN XII (hypoglossal) .
5. Which nerve root is primarily tested by the brachioradialis reflex?
• A. C5
• B. C6
• C. C7
, • D. C8
Correct Answer: B. C6
Rationale: The brachioradialis muscle is innervated by the radial nerve, primarily
receiving contributions from the C6 nerve root. This is a key clinical localizing
sign .
6. A 52-year-old man drinks wood alcohol (methanol). Fundoscopy shows
retinal congestion and blurred disc edges. What causes the ocular toxicity?
• A. Methanol
• B. Formaldehyde
• C. Formic acid
• D. Ethanol
Correct Answer: C. Formic acid
Rationale: Methanol is metabolized by alcohol dehydrogenase to formaldehyde,
then to formic acid. Formic acid is the toxic metabolite that causes metabolic
acidosis and retinal toxicity (optic neuritis) .
7. A patient presents with acute onset of severe "thunderclap" headache and
nuchal rigidity. Non-contrast CT of the head is normal. What is the next best
step?
• A. Discharge patient with migraine medication
• B. CT Angiography
• C. Lumbar puncture
• D. MRI brain with contrast
Correct Answer: C. Lumbar puncture
Rationale: This presentation suggests subarachnoid hemorrhage. If CT is negative
(high sensitivity but misses ~5-10%), an LP must be performed to look for
xanthochromia or red blood cells in the CSF.
8. A 70-year-old patient has a tremor that is present at rest and decreases with
voluntary movement. This is most suggestive of?
• A. Essential tremor
• B. Parkinson’s disease
