Diseases of the nervous system .. . ence of function whichappear at the upper limitgenerally overshadow thoseproduced by pressure ofthe tumor upon the totaltransverse section of thespinal cord. It is easierto ascertain the longitu-dinal extension of the tu-mor within the cervicalenlargement, for when themuscles of the lower cer-vical segments remain un-involved there is no strongpressure upon these. Whenthe tumor is located op-posite the lower portion ofthe dorsal cord, and whenthe muscles belonging toit continue to show nodegenerative atrophy norDeR, we may concludethat it does not press upon
Diseases of the nervous system .. . ence of function whichappear at the upper limitgenerally overshadow thoseproduced by pressure ofthe tumor upon the totaltransverse section of thespinal cord. It is easierto ascertain the longitu-dinal extension of the tu-mor within the cervicalenlargement, for when themuscles of the lower cer-vical segments remain un-involved there is no strongpressure upon these. Whenthe tumor is located op-posite the lower portion ofthe dorsal cord, and whenthe muscles belonging toit continue to show nodegenerative atrophy norDeR, we may concludethat it does not press uponthe upper portion of thelumbar enlargement. Howmany segments are com-pressed within the dorsalcord cannot be statedfrom our present knowl-edge. Examination ofthe abdominal reflexespermits no positive con-clusions because these re-flexes may be abolishedeven when a circumscribedtumor is in a high loca-tion. Their appearance,even if only partial,would contraindicate theextension of a tumor downward. Fig. 156.—Diagram. (After Head.). 360 NEOPLASMS OF THE SPINAL CORD AND OF ITS MEMBRANES The aljsence of tlie tendo7i reflexes must be cautiously utilized, for this isobserved even when there is no direct pressure upon the segments belongingthereto. When there is an acute transverse interruption of the spinal cord above the. lumbar enlargement, thepatella and Achilles tendon | a ^m liiiil BA 10 \ii\ m I- g Fig. 157.—Diagram. (After Head.) Fig. 158.—Diagram. (After Gowers.) THE SEAT, EXTENSION AND COMPOSITION 361 usually disappear.^ On the other hand, their jDresence or increase shows thatthere is no pressure in the corresponding segments. Little is revealed by pain and paresthesia remote from the upper borderof the tumor in deeper situated segments of the spinal cord and the cutaneousareas belonging thereto (for example, in the legs from tumors of the cervicalcord) ; for these abnormal sensations may likewise appear when there is pres-sur
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