TUMORS OF THE PONS give rise to dis tinct, but variable, symptoms, depending upon the size and exact location of the growth. A tumor may be situated to one side of the pons and cause decided pontile symptoms from direct pressure, and if the pons is pushed to one side, against the bony structure, as not infre quently happens, the indirect-pressure symptoms on the opposite side of the pons from the scat of the tumor may be very pronounced. If the tumor is situ ated in the upper portion of the pons, on one side there will be "crossed paral ysis," and possibly heiniamesthesia, as in tumor of the crus. During the irritative stage of the sixth nerve, the eyes may be spasmodically jerked toward the side of the lesion, but when this nerve is para lyzed conjugate deviation of the eyes will be to the opposite side. The symptoms from a tumor in the upper portion of the pons on one side, if from diffusion of irritation the sensory tract on the op posite side is not affected, would be con jugate deviation of the eyes to the op posite side, weakness or paralysis, and dis turbances of sensation throughout the entire opposite side of body, head, and face. Owing, however, to the diffuse character of the symptoms, both direct and indirect from tumor of the upper portion of the pons, the symptoms are more likely to be dilatation of the pupils, ptosis; strabismus, at times; sometimes cloudiness and ulceration of the cornea; pain, with hyperanthesia and anesthesia in the region of the distribution of the fifth nerve on side corresponding to that of the tumor; and hemiplegia and hem iamEsthesia of the opposite side of the body and face, the latter if the lesion extends deep in the substance of the pons, often in the form of dissociation of sensory symptoms (loss of pain and tem perature sensations; tactile preserved) and loss of conjugate movement of the eyes toward the side of the lesion. Other
cranial nerves would probably be affected as the disease progressed. A tumor situ ated in the lower half of the pons on one side would give rise to crossed motor and sensory paralysis; the face, both the lower and upper on the side of the lesion; the body and limbs on the opposite side. Marked trophic disturbances usually oc cur through the distribution of the af fected fifth cranial nerve. Articulation, deglutition, and respiration become af fected in lesions of the extreme lower portion of the pons from the involvement of other cranial nerves. As a rule, these are late symptoms in the course of the disease. Tumors lying between the pons and dura often cause bilateral symptoms on account of the cord being pushed against the bony structure. They differ from those caused by tumors within the pons in being more irritative and less de structive in character until late in the course of these growths, and cranial nerve symptoms precede those of the pons.
Glycosuria and albuminuria may oc cur, giddiness is often intense, and vom iting troublesome if the middle peduncle of the pons is involved. The tumor may directly affect both sides of the pons and produce bilateral symptoms. The knee jerks are as frequently absent as present, and are extremely variable: present and exaggerated at one time, normal or ab sent at another.