日本人胎児の泌尿器科的研究 (第IV編) : 尿管の発育に関する形態学的研究

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Investigations on the origin and development of the ureter are few. The ureter lies in the sacral fossa during the early fetal stage, and, accompanying the developmental ascent of the kidney, it also grows and develops, but it undergoes rather complicated changes at various stages, finally appears to form a complex structure during the last stage, such as seen in the adult. In the present investigation, the another attempted construction of retrograde pyeloureteral figures using 200 fetuses ranging in age from 4th to 10th fetal months, from which 120 specimens were selected on the basis of quality enabling satisfactory observations. The measured values were calculated from the combination of various lines and angles (compare the figures this month) with the first base line, corresponding to the longitudinal line dividing the verteral bodies into two equal halves, and with the second base line which is the conjugate of iliac arests on both sides. Statistical tables of the values so obtained were then analyzed in respect to sexes and fetal months. 1) Position of the transition (point A) of the pelvis to the ureter. During the 4th fetal month, this point is at the lower third of lumbal III on the right, but it is in the middle of lumbal III and IV on the left. During the 10th fetal month, however, it lies at the lower third ,on the right but on the left it ascends to the middle one-third of lumbal II. 2) Position of the first constriction (point B) of the ureter. During the 4th fetal month, this point is located at the lower third of lumbal III on the right and at the lower third of lumbal IV on the left. 3) Position of the second constriction (point C) of the ureter. The exact location of this point is not clear during the 4th fetal month, but during the following month it lies in the the middle of sacral III and IV on the right and at the middle third of sacral III on the left. However, during the 10th fetal month this point is found in the middle third of sacral II and III on both sides. 4) The portion of the ureter in closest contact with the first base line. During the 4th fetal month this portion lies at the lower third of lumbar V on the right and at the middle of lumbal V and sacral I on the left. However, during the 10th fetal month it moves up to the upper third of sacral III on the right and to the middle third of sacral II on the left. 5) The portion of the ureter farthest removed from the first base line is found during the 4th fetal month to be at the middle third of lumbal IV on the right, but on the left it is in the middle of lumbal III and IV. During the 10th fetal month it is in the middle of lumbal III-IV on the right, and on the left it is at the upper third of lumbal III. 6) Growth of points B and C of the ureter. During the 5th fetal month the right side shows a growth of 23.2 mm. and the left 21.06 mm. These figures in crease to 46.24 mm on the right and 47.00 mm on the left during the 10th fetal month. 7) The first angle of directional line (the angle formed by the line drawn from the pyeloureteral transition point to the first constriction of the ureter and the first base line) measures approximately 40° on both sides and shows no change throughout the entire fetal life. 8) The second angle of directional line (the angle formed by the line drawn from the second to the second constriction of the ureter and the first base line) changes from about 10° during the 4th fetal month on both sides to approximately 5° during the 10th fetal month. 9) The third angle of directional line (the angle formed by the line from the second to the third constriction of the ureter and the first base line) is about 43° on the right and 37.1° on the left during the 5th fetal month. During the 10th month, however, it becomes 24.4° on the right and 30.1° on the left. 10) The position of the passage of the ureter was determined by the distance from the original point on the second base line. During the 4th fetal month it was 3.8 mm. On both sides but grows to 11.58 mm. During the 10th fetal month on both sides. 11) In regard to the size of the ureter, the maximal width grows from 1.25 mm on both sides seen during the 4th fetal month to about 3.46 mm on the right and 3.29 mm on the left attained during the 10th fetal month. The minimal width is about 0.7 mm on the right and 0.75 mm on the left during the 4th month, but during the 10th fetal month the right measures 0.89 mm and the left 0.99 mm. There being very little difference between the two sides. 12) With respect to the tortuosity of the ureter, there are variations from month to month and from case to case, but these have been lassified into 5 varieties and 12 types. With this classification in mind, it is noted that both right and left sides show a linear course during the 4th fetal month, but during the 5-6th months, it suddenly exhibits a serpentine tortuosity. This disappears once more during the 6-7 months only to resume the original shape in a variety of bends and curves during the 8th fetal month. The tortuosity becomes mild gradually during the 10th month and approaches the adult type by losing some of the bends. As above summarized, the author made morphologic observations of the ureter from many angles by utilizing ureterograms in fetuses. The most significant finding is the fact that the ureter not only grows and develops assosiated with the ascent of the kidney resulting from the body growth, but also it itself exhibits its own mode of development and extends with the body growth, finally to assume a so-called normal course. Throughout the developmental stage of the fetus, the ureter passes through morphologic changes such as bends and swellings. The form the ureter takes in each case seems to persist as a tendency in later life.
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日本人胎児の泌尿器科的研究 (第IV編) : 尿管の発育に関する形態学的研究

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