Now that the cranial cavity is being opened by surgeons with less and less reluctance, the differential diagnosis between a lesion within the brain substance and one on the surface becomes of increasing importance. Especially is this true of tumors of the posterior fossa, in which field have been made some of the most recent advances in the art of intracranial surgery. Cushing's book, "Tumors of the Nervus Acusticus" indicates what measure of success has been attained.
Since cerebellopontile angle tumors are accessible, and intrapontile tumors inaccessible, naturally the diagnosis between them should anticipate operation. Tumors of the angle by pressure can cause many of the paralyses, anesthesias and ataxias caused by intrapontile lesions. There is, however, one symptom very characteristic of a lesion within the pons that has not been successfully produced by an acoustic tumor. Though Frankl-Hochwart, Alexander, Cushing and Henschen have reported cases in which associated movements
FREEMAN W. PARALYSIS OF ASSOCIATED LATERAL MOVEMENTS OF THE EYESA SYMPTOM OF INTRAPONTILE LESION. Arch NeurPsych. 1922;7(4):454-487. doi:10.1001/archneurpsyc.1922.02190100039002