This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'Which of the following statement is not true about the Trochlear nerve? \nSelect and explain. \nA. It has the longest intracranial course, B. It innervates superior oblique muscle, which depress the eye in abduction and detes the eyeball, C. It is the only cranial nerve that arises from the dorsal aspect of the brainstem, D. It enters the orbit through the superior orbital fissure outside the annulus of Zinn', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Trochlear nerve is the fouh cranial nerve. It is a motor nerve ( somatic efferent nerve), whichinnervates superior oblique muscle, which depress the eye in adduction and in cyclodetes the eyeball.It is the smallest nerve in terms of the number of axons it contains. Other than the optic nerve (cranial nerve II), it is the only cranial nerve that decussates(crosses to the other side) before innervating its target.Finally, it is the only cranial nerve that exits from the dorsal aspect of the brainstem.Injury to the trochlear nerve cause weakness of downward eye movement with consequent veical diplopia (double vision).', 'role': 'assistant'}]