Neuroanatomy USMLE Step 1 Practice Question
A 34-year-old man presents with a penetrating left chest wound. Vital signs show BP 128/82, HR 92, RR 18, temp 37.2°C, SpO2 98%. He develops left-sided Horner syndrome and left arm weakness with loss of pain and temperature sensation on the right leg below T10. MRI reveals a left-sided spinal cord lesion at T1 without cord transection. He denies bowel/bladder dysfunction. Which spinal cord structure is most likely damaged?
Answer choices
- ARight lateral corticospinal tract
- BCentral gray matter bilaterally
- CLeft lateral funiculus containing sympathetic fibers and spinothalamic tractCorrect answer
- DLeft ventral corticospinal tract
- ERight dorsal column (fasciculus gracilis)
- FLeft dorsal root and dorsal column at T1 level
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