NEURO EXAM 1 USAHS ACTUAL 2026
QUESTIONS AND VERIFIED ANSWERS.
SECTION 1: CRANIAL NERVES I-XII (Questions 1–12)
Q1: A patient presents with anosmia following a head injury. Which cranial nerve is most likely
affected?
• A. CN II (Optic nerve)
• B. CN III (Oculomotor nerve)
• C. CN I (Olfactory nerve) ✓
• D. CN V (Trigeminal nerve)
Correct Answer: C Rationale: Correct because anosmia (loss of smell) directly implicates CN I,
the olfactory nerve, which transmits olfactory information from the nasal epithelium through
the cribriform plate to the olfactory bulb. Standard USAHS curriculum requires recognition that
CN I is the only cranial nerve that does not pass through the brainstem.
Q2: During a clinical examination, a patient is unable to look down and inward toward the nose.
Which cranial nerve is responsible for this deficit?
• A. CN III (Oculomotor nerve)
• B. CN IV (Trochlear nerve) ✓
• C. CN VI (Abducens nerve)
• D. CN V (Trigeminal nerve)
Correct Answer: B Rationale: Correct because the trochlear nerve (CN IV) innervates the
superior oblique muscle, which enables downward and inward gaze. Per clinical neuroscience
principles, CN IV is unique in that it exits dorsally from the midbrain and decussates, making it
susceptible to contralateral injury patterns.
Q3: A patient reports loss of sensation over the cheek and upper jaw. Which division of the
trigeminal nerve is affected?
, • A. Ophthalmic division (V1)
• B. Maxillary division (V2) ✓
• C. Mandibular division (V3)
• D. All three divisions
Correct Answer: B Rationale: Correct because the maxillary division (V2) of the trigeminal nerve
provides sensory innervation to the skin of the cheek, upper lip, lateral nose, and upper jaw.
The anatomical pathway dictates that V2 exits the skull via the foramen rotundum, making it
vulnerable to maxillary sinus pathology.
Q4: During a cranial nerve examination, a patient is unable to abduct the left eye. Which nerve
is most likely lesioned?
• A. CN III (Oculomotor nerve)
• B. CN IV (Trochlear nerve)
• C. CN VI (Abducens nerve) ✓
• D. CN VII (Facial nerve)
Correct Answer: C Rationale: Correct because the abducens nerve (CN VI) innervates the lateral
rectus muscle, which abducts the eye. Standard USAHS curriculum requires recognition that CN
VI has the longest intracranial course of all cranial nerves, making it particularly vulnerable to
increased intracranial pressure.
Q5: A patient presents with facial asymmetry, inability to wrinkle the forehead on the right side,
and loss of taste on the anterior two-thirds of the tongue. Which cranial nerve is affected?
• A. CN V (Trigeminal nerve)
• B. CN VII (Facial nerve) ✓
• C. CN IX (Glossopharyngeal nerve)
• D. CN XI (Spinal accessory nerve)
Correct Answer: B Rationale: Correct because the facial nerve (CN VII) controls facial expression
via the facial muscles, carries taste from the anterior two-thirds of the tongue via the chorda
tympani, and regulates lacrimal and salivary secretion. Per clinical neuroscience principles,
,upper motor neuron lesions spare the forehead due to bilateral cortical innervation, whereas
lower motor neuron lesions (as described) affect the entire ipsilateral face.
Q6: A 45-year-old patient reports progressive hearing loss and vertigo. During examination, the
Rinne test shows bone conduction greater than air conduction in the left ear. Which cranial
nerve and associated structure are most likely involved?
• A. CN V (Trigeminal nerve) and trigeminal ganglion
• B. CN VIII (Vestibulocochlear nerve) and cochlea ✓
• C. CN VII (Facial nerve) and facial canal
• D. CN IX (Glossopharyngeal nerve) and otic ganglion
Correct Answer: B Rationale: Correct because the vestibulocochlear nerve (CN VIII) mediates
both hearing (cochlear division) and equilibrium (vestibular division). The Rinne test result
indicates sensorineural hearing loss (air conduction < bone conduction), which localizes the
lesion to the cochlea or CN VIII itself. Standard USAHS curriculum requires differentiation
between conductive and sensorineural hearing loss patterns.
Q7: During a neurologic examination, a patient demonstrates an absent gag reflex on the left
side. Which cranial nerve is most likely lesioned?
• A. CN VII (Facial nerve)
• B. CN VIII (Vestibulocochlear nerve)
• C. CN IX (Glossopharyngeal nerve) ✓
• D. CN X (Vagus nerve)
Correct Answer: C Rationale: Correct because the glossopharyngeal nerve (CN IX) carries the
afferent (sensory) limb of the gag reflex from the posterior one-third of the tongue and pharynx.
The anatomical pathway dictates that an absent gag reflex indicates a lesion of the afferent
pathway, which is mediated by CN IX, whereas the efferent (motor) response is carried by CN X.
Q8: A patient with a suspected brainstem lesion is asked to say "ah." The uvula deviates to the
right side. Which cranial nerve is most likely affected on the left side?
• A. CN IX (Glossopharyngeal nerve)
, • B. CN X (Vagus nerve) ✓
• C. CN XI (Spinal accessory nerve)
• D. CN XII (Hypoglossal nerve)
Correct Answer: B Rationale: Correct because the vagus nerve (CN X) innervates the pharyngeal
muscles via the pharyngeal plexus, including the levator veli palatini, which elevates the soft
palate. Per clinical neuroscience principles, uvula deviation away from the side of the lesion
indicates ipsilateral CN X palsy, as the intact contralateral side pulls the uvula toward it.
Q9: A patient presents with weakness during shoulder shrug on the right side. Which cranial
nerve should be assessed?
• A. CN X (Vagus nerve)
• B. CN XI (Spinal accessory nerve) ✓
• C. CN XII (Hypoglossal nerve)
• D. CN VII (Facial nerve)
Correct Answer: B Rationale: Correct because the spinal accessory nerve (CN XI) provides
motor innervation to the trapezius muscle, which elevates the scapula and enables shoulder
shrugging. Standard USAHS curriculum requires recognition that CN XI also innervates the
sternocleidomastoid (SCM) muscle, and testing both actions provides comprehensive
assessment of this nerve.
Q10: During a neurologic examination, a patient protrudes the tongue and it deviates to the left.
Which cranial nerve is most likely affected?
• A. CN X (Vagus nerve)
• B. CN XI (Spinal accessory nerve)
• C. CN XII (Hypoglossal nerve) ✓
• D. CN IX (Glossopharyngeal nerve)
Correct Answer: C Rationale: Correct because the hypoglossal nerve (CN XII) innervates the
intrinsic and extrinsic muscles of the tongue. Per clinical neuroscience principles, tongue
deviation occurs toward the side of the lesion because the genioglossus muscle on the intact
QUESTIONS AND VERIFIED ANSWERS.
SECTION 1: CRANIAL NERVES I-XII (Questions 1–12)
Q1: A patient presents with anosmia following a head injury. Which cranial nerve is most likely
affected?
• A. CN II (Optic nerve)
• B. CN III (Oculomotor nerve)
• C. CN I (Olfactory nerve) ✓
• D. CN V (Trigeminal nerve)
Correct Answer: C Rationale: Correct because anosmia (loss of smell) directly implicates CN I,
the olfactory nerve, which transmits olfactory information from the nasal epithelium through
the cribriform plate to the olfactory bulb. Standard USAHS curriculum requires recognition that
CN I is the only cranial nerve that does not pass through the brainstem.
Q2: During a clinical examination, a patient is unable to look down and inward toward the nose.
Which cranial nerve is responsible for this deficit?
• A. CN III (Oculomotor nerve)
• B. CN IV (Trochlear nerve) ✓
• C. CN VI (Abducens nerve)
• D. CN V (Trigeminal nerve)
Correct Answer: B Rationale: Correct because the trochlear nerve (CN IV) innervates the
superior oblique muscle, which enables downward and inward gaze. Per clinical neuroscience
principles, CN IV is unique in that it exits dorsally from the midbrain and decussates, making it
susceptible to contralateral injury patterns.
Q3: A patient reports loss of sensation over the cheek and upper jaw. Which division of the
trigeminal nerve is affected?
, • A. Ophthalmic division (V1)
• B. Maxillary division (V2) ✓
• C. Mandibular division (V3)
• D. All three divisions
Correct Answer: B Rationale: Correct because the maxillary division (V2) of the trigeminal nerve
provides sensory innervation to the skin of the cheek, upper lip, lateral nose, and upper jaw.
The anatomical pathway dictates that V2 exits the skull via the foramen rotundum, making it
vulnerable to maxillary sinus pathology.
Q4: During a cranial nerve examination, a patient is unable to abduct the left eye. Which nerve
is most likely lesioned?
• A. CN III (Oculomotor nerve)
• B. CN IV (Trochlear nerve)
• C. CN VI (Abducens nerve) ✓
• D. CN VII (Facial nerve)
Correct Answer: C Rationale: Correct because the abducens nerve (CN VI) innervates the lateral
rectus muscle, which abducts the eye. Standard USAHS curriculum requires recognition that CN
VI has the longest intracranial course of all cranial nerves, making it particularly vulnerable to
increased intracranial pressure.
Q5: A patient presents with facial asymmetry, inability to wrinkle the forehead on the right side,
and loss of taste on the anterior two-thirds of the tongue. Which cranial nerve is affected?
• A. CN V (Trigeminal nerve)
• B. CN VII (Facial nerve) ✓
• C. CN IX (Glossopharyngeal nerve)
• D. CN XI (Spinal accessory nerve)
Correct Answer: B Rationale: Correct because the facial nerve (CN VII) controls facial expression
via the facial muscles, carries taste from the anterior two-thirds of the tongue via the chorda
tympani, and regulates lacrimal and salivary secretion. Per clinical neuroscience principles,
,upper motor neuron lesions spare the forehead due to bilateral cortical innervation, whereas
lower motor neuron lesions (as described) affect the entire ipsilateral face.
Q6: A 45-year-old patient reports progressive hearing loss and vertigo. During examination, the
Rinne test shows bone conduction greater than air conduction in the left ear. Which cranial
nerve and associated structure are most likely involved?
• A. CN V (Trigeminal nerve) and trigeminal ganglion
• B. CN VIII (Vestibulocochlear nerve) and cochlea ✓
• C. CN VII (Facial nerve) and facial canal
• D. CN IX (Glossopharyngeal nerve) and otic ganglion
Correct Answer: B Rationale: Correct because the vestibulocochlear nerve (CN VIII) mediates
both hearing (cochlear division) and equilibrium (vestibular division). The Rinne test result
indicates sensorineural hearing loss (air conduction < bone conduction), which localizes the
lesion to the cochlea or CN VIII itself. Standard USAHS curriculum requires differentiation
between conductive and sensorineural hearing loss patterns.
Q7: During a neurologic examination, a patient demonstrates an absent gag reflex on the left
side. Which cranial nerve is most likely lesioned?
• A. CN VII (Facial nerve)
• B. CN VIII (Vestibulocochlear nerve)
• C. CN IX (Glossopharyngeal nerve) ✓
• D. CN X (Vagus nerve)
Correct Answer: C Rationale: Correct because the glossopharyngeal nerve (CN IX) carries the
afferent (sensory) limb of the gag reflex from the posterior one-third of the tongue and pharynx.
The anatomical pathway dictates that an absent gag reflex indicates a lesion of the afferent
pathway, which is mediated by CN IX, whereas the efferent (motor) response is carried by CN X.
Q8: A patient with a suspected brainstem lesion is asked to say "ah." The uvula deviates to the
right side. Which cranial nerve is most likely affected on the left side?
• A. CN IX (Glossopharyngeal nerve)
, • B. CN X (Vagus nerve) ✓
• C. CN XI (Spinal accessory nerve)
• D. CN XII (Hypoglossal nerve)
Correct Answer: B Rationale: Correct because the vagus nerve (CN X) innervates the pharyngeal
muscles via the pharyngeal plexus, including the levator veli palatini, which elevates the soft
palate. Per clinical neuroscience principles, uvula deviation away from the side of the lesion
indicates ipsilateral CN X palsy, as the intact contralateral side pulls the uvula toward it.
Q9: A patient presents with weakness during shoulder shrug on the right side. Which cranial
nerve should be assessed?
• A. CN X (Vagus nerve)
• B. CN XI (Spinal accessory nerve) ✓
• C. CN XII (Hypoglossal nerve)
• D. CN VII (Facial nerve)
Correct Answer: B Rationale: Correct because the spinal accessory nerve (CN XI) provides
motor innervation to the trapezius muscle, which elevates the scapula and enables shoulder
shrugging. Standard USAHS curriculum requires recognition that CN XI also innervates the
sternocleidomastoid (SCM) muscle, and testing both actions provides comprehensive
assessment of this nerve.
Q10: During a neurologic examination, a patient protrudes the tongue and it deviates to the left.
Which cranial nerve is most likely affected?
• A. CN X (Vagus nerve)
• B. CN XI (Spinal accessory nerve)
• C. CN XII (Hypoglossal nerve) ✓
• D. CN IX (Glossopharyngeal nerve)
Correct Answer: C Rationale: Correct because the hypoglossal nerve (CN XII) innervates the
intrinsic and extrinsic muscles of the tongue. Per clinical neuroscience principles, tongue
deviation occurs toward the side of the lesion because the genioglossus muscle on the intact
