A 67-year-old man with hypertension presents with acute-onset right facial droop and arm weakness. Vital signs: BP 158/92, HR 88, RR 16, Temp 37°C, SpO2 98%. Neurologic exam reveals right arm weakness (2/5) greater than right leg weakness (4/5); facial droop present. MRI confirms acute left middle cerebral artery stroke involving the motor cortex. Serum glucose 118 mg/dL. No aphasia or visual field deficits noted. Which anatomical organization of the motor cortex best explains this selective weakness pattern?
- A)The primary motor cortex is located in the postcentral gyrus
- B)The corticospinal tract decussates at the level of the midbrain
- C)The motor cortex lacks innervation to muscles of facial expression
- D)The motor cortex has greater cortical representation for upper extremities than lower extremitiesGABARITO
- E)Lower extremity motor control is exclusively ipsilateral
Explicação
The motor cortex has a somatotopic organization where the upper extremity occupies a larger cortical territory (motor homunculus). A stroke affecting the primary motor cortex disproportionately impacts upper extremity function more than lower extremity functio... Ver explicação completa e trilha adaptativa →