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MOTOR SYSTEMS

A patient delays initiation of movement, displays an uneven trajectory in moving her hand from above her head to touch her nose, and is uneven in her attempts to demonstrate “rapid alerting movements.” Which of the following regions most likely contains the lesion?

a. Hemispheres of the posterior cerebellar lobe

b. Flocculonodular lobe of the cerebellum

c. Vermal region of the anterior cerebellar lobe

d. Fastigial nucleus

e. Ventral spinocerebellar tract

The answer is A. (Nolte, pp 520-521. Siegel and Sapru, pp 358-374.) The classic appearance of a patient with a lesion of the cerebellar hemispheres is one in which voluntary and skilled movements are affected. They are uncoordinated, and there are errors in the range, force, and direction of movement. The relationships between the cerebellum and the motor regions of the cerebral cortex have been disrupted. Lesions of other regions, such as the flocculonodular lobe, vermal region of the anterior cerebellar cortex, or fastigial nucleus, produce different symptoms (disturbances of balance and nystagmus associated with the flocculonodular lobe and vermal regions, disturbances of muscle tone associated with the anterior cerebellar cortex). Although pure lesions limited to the ventral spinocerebellar tract have not been reported, it is likely that such a lesion could not account for the symptoms indicated in this question. Information carried by this tract concerns activity of Golgi tendon organs of muscles of the lower limbs.

A 74-year-old woman with a history of hypertension suddenly displays loss of consciousness. Sometime later, the patient presents with weakness of her left body, including upper and lower limbs, weakness of her face, and slurred speech. The diffusion-weighted magnetic resonance imaging (MRI) of this patient is shown here, in which the high signal reflects vascular occlusion of a region of the brain. Which of the following best characterizes what happened to this patient?

(Reproduced, with permission, from Anschel DJ, Romanelli P, Mazumdar A. McGraw-Hill Specialty Board Review: Clinical Neuroimaging. New York: McGraw-Hill; 2008:45.)

a. A stroke involving the right anterior cerebral artery

b. A stroke involving the right middle cerebral artery

c. Occlusion of the right anterior communicating artery

d. Occlusion of the right posterior communicating artery

e. A stroke of the posterior cerebral artery

The answer is B. (Anschel, p 45. Ropper, pp 667-673.) This patient suffered a stroke of the middle cerebral artery and ...

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