Ando T

MORPHOMETRY OF THE NORMAL CADAVERIC CERVICAL SPINAL CORD

Study Design The authors measured the transverse area and diameters of the cadaveric cervical spinal cord without evidence of nervous system pathology and also investigated factors related to spinal cord size. Objectives This study attempted to provide basic data that affords an accurate morphometric analysis of the human cervical spinal cord. Summary of Background Data Several postmortem morphometric studies of the spinal cord have been performed, but the measurements are different among the reports, and no authorized standard has been established. Methods The authors measured the transverse area and diameters of the C7 segment in 152 cadaveric specimens and investigated the cord size in relation to age, body height, body weight, and brain weight. Of these, 14 cases were selected and their segments from C2 to T1 were measured. Results There was a considerable individual variation in spinal cord size. The transverse area of the C7 segment varied from 33.3 mm2 to 74.0 mm2 (mean 49.6 ± 7.4 mm2). The cord size showed a strong correlation with brain weight, and to a lesser degree with age and body height. Although the size of the spinal cord varied from case to case, the relative ratio of the transverse area of each segment to that of the C3 segment was almost the same among the cases examined. Conclusions This large variation in cord size should be taken under consideration in morphometric analyses of the spinal cord. When the pathologic cord conditions such as compression or atrophy exist, the normally expected transverse area of the affected segment in each individual is calculable from measurement of a given single normal segment.

Pathology of spinal vascular disease

Pathological changes of spinal vascular disease due to dissecting aortic aneurysm, atheroma emboli, cardiac arrest and pencil‐shaped softening are described. Spinal cord damage in four patients who developed paraplegia secondary to the dissecting aortic aneurysm varied significantly from case to case. The extent of aortic dissection, the level of radicular artery, the vascular supply pattern in the transverse section of the spinal cord, and the vulnerability to ischemia were suggested to be very important factors contributing to the spinal cord damage. Atheroma emboli of spinal cord vessels were found in 7/604 autopsied cases. Atheroma emboli of spinal cord vessels is one cause of myelopathy in aged persons with hypertension, renal failure, myocardial infarction, or diabetis mellitus. Atheroma emboli were often observed at the vessels of lumbosacral segmental level. Necrosis of the spinal cord was only observed in two cases of atheroma emboli. Ischemic changes of the spinal cord were observed in 7/15 cases in which the cerebral cortex showed lamellar necrosis due to cardiac arrest. The damaged areas were found more predominantly in the lumbosacral segment. In the cross section, the area from the mid‐portion of gray matter to the base of the posterior horn was predominantly affected. Histological findings of 13 cases of pencil‐shaped softening, in which the spinal cord showed transverse necrosis by compression of extradural metastatic tumors are described. The continuity between the cavity of pencil‐shaped softening, the area of transverse necrosis was confirmed. For the pathogenesis of pencil‐shaped softening, mechanical compression was considered to be an important factor.

A study of interfacial flow due to concentration difference

Abstract Experiments were carried out to study the effect of concentration differences on the surface-velocity distribution. The surface-velocity induced by feeding the surface-tension lowering material onto the surface of the stagnant liquid was measured in a similar type of apparatus to that used by Ruckenstein et al. [1]. The system studied was ethanol-water. From the experimental results, the dependence of surface-velocity distribution on the bulk viscosity of the solution, degree of surface contamination and concentration and feed rate of alcohol, was discussed.