Motor pathwaysDownloads

An otherwise healthy 43-year-old woman comes to the physician because of several episodes of involuntary movements of her head over the past few months. They are sometimes associated with neck pain and last minutes to hours. Neurologic examination shows no abnormalities. During examination of the neck, the patient's head turns horizontally to the left. She states this movement is involuntary, and that she is unable to unturn her head. After 5 minutes, her head re-straightens. Which of the following best describes this patient's disorder?

A 20-year-old man is brought to the emergency department 20 minutes after he sustained a stab wound to his back during an altercation. He reports weakness and numbness of the lower extremities. He has no history of serious illness. On arrival, he is alert and cooperative. His pulse is 90/min, and blood pressure is 100/65 mm Hg. Examination shows a deep 4-cm laceration on his back next to the vertebral column at the level of the T10 vertebra. Neurologic examination shows right-sided motor weakness with diminished vibratory sense ipsilaterally, decreased sensation to light touch at the level of his laceration and below, and left-sided loss of hot, cold, and pin-prick sensation at the level of the umbilicus and below. Deep tendon reflexes of his right lower extremity are 4+ and symmetrical. Babinski sign is absent bilaterally. The remainder of the examination shows no abnormalities. Which of the following is the most likely diagnosis?