1
COMSAE Phase 1 Information – The Complete 176
Question Test Bank All questions with correct verified
answers & detailed rationales – graded A+ for the
newest 2026 actual exam
COMSAE Phase 1 – 176 Questions with Verified Answers & Detailed Rationales
Section 1: Anatomy & Neuroanatomy (Questions 1–25)
1. A 45-year-old man presents with loss of sensation on the medial forearm and
weakness of finger abduction and adduction after a knife wound to the upper
arm. Which nerve is most likely injured?
A. Median nerve
B. Radial nerve
C. Ulnar nerve
D. Musculocutaneous nerve
: Correct Answer : C. Ulnar nerve
Rationale: The ulnar nerve innervates the intrinsic hand muscles (interossei)
responsible for finger abduction/adduction and provides sensation to the medial
forearm and hand. A wound to the upper medial arm could injure the ulnar nerve.
The median nerve controls thumb opposition and lateral palm sensation.
2. A 60-year-old woman suddenly develops vertigo, dysphagia, loss of pain and
temperature on the left side of her face and right side of her body. Which artery
is most likely occluded?
A. Anterior spinal artery
B. Posterior inferior cerebellar artery (PICA)
C. Anterior inferior cerebellar artery (AICA)
D. Basilar artery
pg. 1
,2
: Correct Answer : B. Posterior inferior cerebellar artery (PICA)
Rationale: PICA occlusion causes lateral medullary (Wallenberg) syndrome,
characterized by ipsilateral facial pain/temperature loss (trigeminal nucleus),
contralateral body pain/temperature loss (spinothalamic tract), vertigo,
dysphagia, and Horner syndrome.
3. A 2-day-old infant has a positive newborn screen for phenylketonuria. Which
amino acid accumulates in the blood?
A. Tyrosine
B. Methionine
C. Phenylalanine
D. Leucine
: Correct Answer : C. Phenylalanine
Rationale: PKU results from deficiency of phenylalanine hydroxylase, causing
accumulation of phenylalanine. If untreated, it leads to intellectual disability.
Tyrosine becomes conditionally essential. Methionine and leucine are not involved.
4. A 70-year-old man with severe emphysema has a barrel-shaped chest and
increased residual volume. Which change in lung compliance is expected?
A. Decreased compliance
B. Increased compliance
C. Normal compliance
D. Increased airway resistance only
: Correct Answer : B. Increased compliance
Rationale: Emphysema destroys elastic fibers, causing loss of elastic recoil and
increased compliance. The lungs are easy to inflate but hard to deflate, leading to
air trapping and increased residual volume.
5. A 34-year-old woman undergoes thyroidectomy and subsequently develops
hoarseness and difficulty swallowing. Which nerve is most likely injured?
A. External laryngeal nerve
pg. 2
,3
B. Recurrent laryngeal nerve
C. Hypoglossal nerve
D. Glossopharyngeal nerve
: Correct Answer : B. Recurrent laryngeal nerve
Rationale: The recurrent laryngeal nerve innervates all intrinsic laryngeal muscles
except the cricothyroid. Injury causes hoarseness and, if bilateral, airway
compromise. It runs close to the thyroid gland.
6. A 55-year-old man has a left homonymous hemianopia with macular sparing
after a stroke. Where is the lesion most likely?
A. Left optic nerve
B. Right optic radiation
C. Left optic radiation
D. Optic chiasm
: Correct Answer : B. Right optic radiation
Rationale: Homonymous hemianopia with macular sparing suggests a lesion in the
optic radiation or visual cortex contralateral to the field loss. Left homonymous
hemianopia results from a right hemisphere lesion. Macular sparing is typical of
vascular lesions in the occipital pole.
7. A 40-year-old man with alcohol use disorder presents with confusion,
nystagmus, and a broad-based gait. Which vitamin deficiency is most likely
responsible?
A. Vitamin B12
B. Thiamine (B1)
C. Niacin (B3)
D. Folate
: Correct Answer : B. Thiamine (B1)
Rationale: Wernicke encephalopathy is caused by thiamine deficiency and
presents with the classic triad: confusion, ophthalmoplegia/nystagmus, and
ataxia. Degeneration involves mammillary bodies and cerebellar vermis.
pg. 3
, 4
8. A newborn has a sac that protrudes through a lower back defect, containing
meninges and cerebrospinal fluid but no neural tissue. What is the diagnosis?
A. Spina bifida occulta
B. Meningocele
C. Myelomeningocele
D. Encephalocele
: Correct Answer : B. Meningocele
Rationale: Meningocele is herniation of meninges and CSF without neural
elements, covered by skin. Myelomeningocele contains neural tissue and is not
covered by skin. Spina bifida occulta is a bony defect without herniation.
9. A 25-year-old woman has a tumor compressing the right optic nerve at the
optic canal. Which visual field defect would be expected?
A. Bitemporal hemianopia
B. Right monocular blindness
C. Left homonymous hemianopia
D. Right nasal hemianopia
: Correct Answer : B. Right monocular blindness
Rationale: A lesion of the optic nerve anterior to the chiasm causes complete
visual loss in the ipsilateral eye. Bitemporal hemianopia occurs with chiasmal
lesions.
10. A 60-year-old man with hypertension has a sudden severe headache and
neck stiffness. CT shows blood in the subarachnoid space. What is the most
common cause?
A. Arteriovenous malformation
B. Ruptured saccular (berry) aneurysm
C. Intracerebral hemorrhage
D. Cavernous angioma
pg. 4
COMSAE Phase 1 Information – The Complete 176
Question Test Bank All questions with correct verified
answers & detailed rationales – graded A+ for the
newest 2026 actual exam
COMSAE Phase 1 – 176 Questions with Verified Answers & Detailed Rationales
Section 1: Anatomy & Neuroanatomy (Questions 1–25)
1. A 45-year-old man presents with loss of sensation on the medial forearm and
weakness of finger abduction and adduction after a knife wound to the upper
arm. Which nerve is most likely injured?
A. Median nerve
B. Radial nerve
C. Ulnar nerve
D. Musculocutaneous nerve
: Correct Answer : C. Ulnar nerve
Rationale: The ulnar nerve innervates the intrinsic hand muscles (interossei)
responsible for finger abduction/adduction and provides sensation to the medial
forearm and hand. A wound to the upper medial arm could injure the ulnar nerve.
The median nerve controls thumb opposition and lateral palm sensation.
2. A 60-year-old woman suddenly develops vertigo, dysphagia, loss of pain and
temperature on the left side of her face and right side of her body. Which artery
is most likely occluded?
A. Anterior spinal artery
B. Posterior inferior cerebellar artery (PICA)
C. Anterior inferior cerebellar artery (AICA)
D. Basilar artery
pg. 1
,2
: Correct Answer : B. Posterior inferior cerebellar artery (PICA)
Rationale: PICA occlusion causes lateral medullary (Wallenberg) syndrome,
characterized by ipsilateral facial pain/temperature loss (trigeminal nucleus),
contralateral body pain/temperature loss (spinothalamic tract), vertigo,
dysphagia, and Horner syndrome.
3. A 2-day-old infant has a positive newborn screen for phenylketonuria. Which
amino acid accumulates in the blood?
A. Tyrosine
B. Methionine
C. Phenylalanine
D. Leucine
: Correct Answer : C. Phenylalanine
Rationale: PKU results from deficiency of phenylalanine hydroxylase, causing
accumulation of phenylalanine. If untreated, it leads to intellectual disability.
Tyrosine becomes conditionally essential. Methionine and leucine are not involved.
4. A 70-year-old man with severe emphysema has a barrel-shaped chest and
increased residual volume. Which change in lung compliance is expected?
A. Decreased compliance
B. Increased compliance
C. Normal compliance
D. Increased airway resistance only
: Correct Answer : B. Increased compliance
Rationale: Emphysema destroys elastic fibers, causing loss of elastic recoil and
increased compliance. The lungs are easy to inflate but hard to deflate, leading to
air trapping and increased residual volume.
5. A 34-year-old woman undergoes thyroidectomy and subsequently develops
hoarseness and difficulty swallowing. Which nerve is most likely injured?
A. External laryngeal nerve
pg. 2
,3
B. Recurrent laryngeal nerve
C. Hypoglossal nerve
D. Glossopharyngeal nerve
: Correct Answer : B. Recurrent laryngeal nerve
Rationale: The recurrent laryngeal nerve innervates all intrinsic laryngeal muscles
except the cricothyroid. Injury causes hoarseness and, if bilateral, airway
compromise. It runs close to the thyroid gland.
6. A 55-year-old man has a left homonymous hemianopia with macular sparing
after a stroke. Where is the lesion most likely?
A. Left optic nerve
B. Right optic radiation
C. Left optic radiation
D. Optic chiasm
: Correct Answer : B. Right optic radiation
Rationale: Homonymous hemianopia with macular sparing suggests a lesion in the
optic radiation or visual cortex contralateral to the field loss. Left homonymous
hemianopia results from a right hemisphere lesion. Macular sparing is typical of
vascular lesions in the occipital pole.
7. A 40-year-old man with alcohol use disorder presents with confusion,
nystagmus, and a broad-based gait. Which vitamin deficiency is most likely
responsible?
A. Vitamin B12
B. Thiamine (B1)
C. Niacin (B3)
D. Folate
: Correct Answer : B. Thiamine (B1)
Rationale: Wernicke encephalopathy is caused by thiamine deficiency and
presents with the classic triad: confusion, ophthalmoplegia/nystagmus, and
ataxia. Degeneration involves mammillary bodies and cerebellar vermis.
pg. 3
, 4
8. A newborn has a sac that protrudes through a lower back defect, containing
meninges and cerebrospinal fluid but no neural tissue. What is the diagnosis?
A. Spina bifida occulta
B. Meningocele
C. Myelomeningocele
D. Encephalocele
: Correct Answer : B. Meningocele
Rationale: Meningocele is herniation of meninges and CSF without neural
elements, covered by skin. Myelomeningocele contains neural tissue and is not
covered by skin. Spina bifida occulta is a bony defect without herniation.
9. A 25-year-old woman has a tumor compressing the right optic nerve at the
optic canal. Which visual field defect would be expected?
A. Bitemporal hemianopia
B. Right monocular blindness
C. Left homonymous hemianopia
D. Right nasal hemianopia
: Correct Answer : B. Right monocular blindness
Rationale: A lesion of the optic nerve anterior to the chiasm causes complete
visual loss in the ipsilateral eye. Bitemporal hemianopia occurs with chiasmal
lesions.
10. A 60-year-old man with hypertension has a sudden severe headache and
neck stiffness. CT shows blood in the subarachnoid space. What is the most
common cause?
A. Arteriovenous malformation
B. Ruptured saccular (berry) aneurysm
C. Intracerebral hemorrhage
D. Cavernous angioma
pg. 4
