Paper - Growth of the human prenatal hypophysis and the hypophyseal fossa: Difference between revisions

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Growth Of The Human Prenatal Hypophysis And The Hypophyseal Fossa
 
W. P. Covell
 
I)oparMnent of Anatomy, U'71i'vcrsiI_1/ of Minnesota
 
Twenty-One Figures
 
CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 379
 
Material and methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 381
 
Absolute growth changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 387
 
1, Lineal dimensions of the gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 388
 
(1. Transverse diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 388
 
b. Anteroposterior diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 389
 
0. Vertical diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i . . . .. 391
 
2. Total weight of the gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 392
 
(1. Embryonic and early fetal life . . . . . . . . . . . . . . . . . . . . . . . . . .. 392
1). Fetal life (in fetuses ranging from 17 to 55 cm., total body
length) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393
 
3. VVeight of the lobes of the gland . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 396
 
a. Embryoilic and early fetal life . . . . . . . . . . . . . . . . . . . . . . . . .. 396
 
1). Fetal life . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 399
 
4. Lineal dimensions of the hypophyseal fossa . . . . . . . . . . . . . . . . . . . .. 404
 
a. Transverse diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 406
 
b. Anteroposterior diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 407
 
c. Vertical diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 407
 
Relative growth changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 407
 
Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i . . . . . . . . . . . . . . . . . 418
 
Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 420
 
Bibliograph_\' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 421
INTRODUCTION
 
For the most part, morphologic observations on the hypophysis have been confined to qualitative studies of its
structure and development. Quantitative data comprise but
a11 exceedingly small portion of the principal contributions to
our general knowledge of this gland.
 
The literature dealing with the dimensional growth of the
prenatal gland and its fossa is scanty, as may be seen from
 
379
380 w. P. COVELL
 
the following brief review bearing on the stages involved in
this study.
 
Schoneman (’92), from a study of six apparently normal
newborn hypopliyses, determined the weight of the gland as
0.13 gram for the newborn. Comte (’98) found the weights
for five glands from postnatal material ranging in age from
ten days to five mo11tl1s to average 0.113 gram. Thelrange in
weight of the glands was 0.095 to 0.125 gram. Cutore (’10)
gives the weights of three hypophyses from fetuses measuring
from 49.5 to 52 cm. in total body length. He found the weight
of one newborn specimen to be 0.032 gram, tl1e remaining
two (of 50 and 52 cm. in body length) were 0.10 gram each.
 
Among the data collected by Parski (’01) are to be found
the weights of three glands from fetuses of about the fifth
fetal month. The average weight for the two of 26 cm. total
body length he gives as 0.018 gram and the weight of the gland
of a fetus of 30 cm. as 0.012 gram. He found the weights of
five hypophyses from fetuses measuring about 50 em. in body
length to range from 0.05 to 0.1 gram. In four infants averaging 57 cm. in total body length he found the range in gland
weight to be between 0.06 and 0.1 gram. ‘
 
Lucien (’11) described the hypophysis as having a weight
of approximately 0.1 gram at birth and as representing
1/44994 of the total body weight in males, from birth to five
years of age, and 1/3252 for females of the same range of age.
He found the diameters of the gland in the course of the first
year of life to be 0.9 cm. transversely, 0.6 cm. a11teroposteri—
orly, by 0.4 em. vertically. He conceived of the idea of representing the volume of the hypophysis i11 terms of an ellipsoid
form by use of the three diameters in the equation for determining the volume of an ellipse. He found the V-olume in cubic
centimeters to be approximated by the following formula:
 
Transverse >< Antcropostcrior >< Vertical
" 0’ 1.91
 
The computed volume of the hypophysis of a newborn, accord
ing to him, is 0.12 cc.
GROWTH or HUMAN PRENATAL HYP()PHYSIS 381
 
Thom (’01) described the average diameters of the anterior
lobe for the neonatal period as 6.75 mm. transversely, 3 mm.
sagittally, and 2.5 mm. vertically. In o11e instance of a six
months’ postnatal male he found the diameters to be 8 mm.
transversely, 3 mm. sagittally (-1.0 mm., including the pars
nervosa), and 3 mm. vertically. According to his findings,
the average diameters of the gland for the first year of life
are 7.35 mm. transversely, 4.11 mm. sagittally, and 2.46 mm.
vertically.
 
I wish to express my appreciation to Prof. A. T. Rasmussen
and Prof. R. E. Scammon for their valuable aid and suggestions during the course of the present study.
 
MATERIAL AND METHODS
 
The material used in this study consisted of ninety—eight
specimens of the hypophysis of prenatal life and fifty of the
hypophyseal fossa. The fetuses were of the Caucasian race
and for the most part of Scandinavian-American parentage.
Eighty—two of the hypophyses were from fetuses ranging in
crown-heel dimension from 15 to 55 cm. and sixteen were from
material of 1.1 to 15 cm., crown-rump. Of the sixteen specimens, which represent the earlier stages of prenatal development, eight were from slides of the embryos in the collection
of the Department of Anatomy, University of Minnesota. The
remaining eight were from material which had been previously preserved in 10 per cent formalin for some time.
Thirty-six of the eighty-two hypophyses of fetal life were
from material which had been similarly treated. The remaining forty-six were from autopsied material of the Department
of Pathology of the University of l\[innesota and a division
of the Children’s Bureau of the Department of Labor, Washington, D. (1., under the supervision of Dr. F. L. Adair. The
fresh glands were fixed in about 33 per cent formalin neutralized with magnesium carbonate, in which they were allowed
to remain from four days to one week.
 
THE AMERICAN JOURNAL OF AN.\'I‘(JMY, V011. 38, NO. I}
382 W. P. COVELL
 
In order to avoid injury to the gland, it was found necessary
to remove the whole sella turcica and so leave the hypophysis
intact in its fossa. Such a procedure was followed for both
fresh and preserved material.
 
After removal of the sella turcica, with the hypophysis in
situ, it was placed in the neutral formalin and the gland later
dissected out. This method has been found by Rasmussen
and Herrick ( ’22) to be the most satisfactory procedure, since
the posterior lobe is too easily injured if an attempt is made
to dissect out the gland from its fossa before fixation. Such
a treatment of the material is also advantageous for a closer
approximation of the true diameters of the hypophysis.
 
In dissecting out the hypophysis from the hypopliyseal
fossa, the dural sheath was first loosened and taken off. After
the gland had been removed from the fossa, the infundibular
stalk was then cut close to the body of the hypophysis. The
organ was then returned to neutral formalin and allowed to
remain for a day or'so longer, i11 order to give ample time for
fixation.
 
Methods of ('0lIc(‘ti1i2g data
 
Before weigliiiig the gland the excess fluid was blotted off
b_v g'e11tly rolling it over on filter—paper. It was then placed
in a moist chamber and readings taken to one—tenth of a
milligram 011 an analytical balance. Three lineal measurements wore then made on each hypophysis by means of steel
Vernier calipers which could be read to one—tenth of a millimeter. Similarly, measurements were recorded on the length,
breadth, and depth of the hypophyseal fossa.
 
The hypophysis was then dehydrated in the usual manner,
cleared in Xylol, and embedded in 55° paraflin after four to
five hours in the paraffin oven. Horizontal sections of 10 ii
in thickness were cut a11d arranged serially. At intervals of
about one—fourth, one-half, and three-fourths of the way
resented every tenth section intermediate between the sections were made.. Every tenth section and in some instances
every fifth section of the series was mounted. For some of
GROWTH or HUMAN PRENATAL HYPOPHYSIS 383
 
the glands two sets of slides were made. The second set represented every tenth section intermediate between the sections of the first series. The mounted sections were usually
stained in l\[allory’s triple connective-tissue stain (acid
fuchsin, aniline blue, and orange G). A few series were
stained in Delafield’s hematoxylin and eosin. The stained
sections were then dehydrated, cleared in xylol, and mounted
in balsam.
 
In order to ascertain the relative volume of each of the
lobes, the method used by Hammar (’14), Jackson (’17), and
Rasmussen and Herrick (’22) was followed. Every mounted
section of the 10 u series was projected, by means of an Edinger projection apparatus, onto paper of standard weight
(about 0.012 gram per 1 sq.cm.). A magnification of about
forty times was used for the glands from fetuses of the latter
half of the fetal period. This was increased to 75 or 100 times
for the material of early prenatal life. The areas of the lobes
were then outlined by means of a sharp hard pencil.
 
The outlined areas were then cut out with a small pair of
scissors and the various parts weighed. The relative proportion which each lobe forms of the total paper weight is then
comparable to that of the fresh gland, providing the shrinkage
of each lobe has been about the same. Jackson (’17) and
Rasmussen and Herrick (’22) found sufficiently close agreement between the glandular and neural portions in this re—
spect. The relative weight of each lobe was determined by
dividing the total paper weight of each lobe by the sum of the
paper weights for the three lobes. It was then possible to
ascertain the absolute weight of each of the lobes from the
original as recorded before embedding.
 
For the embryonic and early fetal material, the hypophysis
was treated in the above manner, with the exception of a
higher magnification (75 or 100 times) and the projection of
every section. In most of this material it was necessary to
obtain an approximation of the weight of the gland from the
total paper weight, since the weight before fixation was not
obtainable. For such a determination it was necessary to
384 w. P. cov ELL
 
approximate the relative amount of shrinkage due to the
process of embedding. This was done by taking measurements on a ‘small part of the body on the drawings (made to
scale) filed in the collection. These measurements were compared with measurements made on the same part after it l1ad
been embedded, sectioned, stained, and mounted. From the
serial sections the weight of the gland was then obtained by
dividing the total paper weight by the weight of 1 sq.cm. of
paper, then further dividing by the magnification squared,
multiplying the result by the thickness of the section (reduced
to centimeters), and finally correcting for the amount of
shrinkage and multiplying by the specific gravity of 1.066
(Vierordt, ’06).
 
Methods of n'cafmc17,t of the data
 
In order to show the changes which occur i11 the hypophysis,
the data approximating the growth changes in weight and
lineal dimensions of the hypophysis and diameters of the
hypophyseal fossa were treated by graphic and analytical
methods. In this analysis the following steps were taken:
1) (.‘onstruction of graphs with the individual cases and average points plotted. 2) Fitting the data to empirical formulae
based on body length. 3) Making tables for comparison of
the observed and calculated values for 5-cm. intervals of
crown-heel or total body length. Tables and a histogram
were compiled to show the relative volumes of the three lobes
of the hypophysis in terms of the body length. Other tables
and curves were made to illustrate the approximate percentage growth of the gland and its fossa in prenatal life.
 
(l«)~22.s*t1"2¢(:t27()2z. of _(;mph.s*. Total or crown—heel body length
in centimeters formed the abscissae of each graph, while the
weight or dimension of the specimen or its part formed the
ordinates. Average points were plotted on the basis of means
of values for 2.5—cm. intervals of crown-heel or total bod_v
length.
 
Iu’cpr(3.s‘c12t(Lti072 of data by cmpz7rical fomnulac. The empirical formulae used for expressing the growth changes in volGROWTH or HUMAN PRENATAL HYPOPHYSIS 385
 
ume and linear measurements were of three different sorts.
The method of approximation employed for the observed
values was the method of averages. The lineal dimensions of
the hypophysis and the hypophyseal fossa when plotted ac«
cording to the crown—heel measurement were found to be approximately expressed by the straight—1ine formula:
Y :: aX + b. \Vhere Y is the value to be determined in centimeters, X is the body length i11 decimeters, and a and I) are
constants which are empirically determined.
 
The formulae for the expression of weight of the gland and
its parts, with the exception of the pars nervosa, during prenatal life have been represented by the following general for—
mula: Y: aX". VVhere Y is the value in question expressed
i11 milligrams, X is the crown—hecl or total body length in
centimeters or decimeters, and a and I) are the empirically
determined constants, a being a decimal fraction and I) a
power. In its logarithmic form the formula reads: Log
Y-.:log a + b log X. Thus the plot of log Y against log X
approximates a straight line.
 
The growth of the pars nervosa of the hypophysis, in
fetuses ranging from 15 to 55 cm. in total body length, was
found to be more readily approximated by means of the following formula: Y = ae"X. VVhere Y is the val11e to be determined in milligrams, a and b are constants to be empirically
determined, e is the base of natural (napierian) logarithms,
and X is the cr0wn~heel or total body length in decimeters.
In this equation the plot of log Y against X approximates a
straight line and the logarithmic expression of the formula is
the following: Log Y :log a + (b log e) X.
 
An example of the method. The three types of empirical
formulae used for expressing i11 numerical terms the growth
of the prenatal hypophysis and its fossa are listed above. The
type of formula used for approximating the growth of the
li11eal dimensions may be expressed as follows: Y = aX -1- b.
In order to develop an expression of this kind from the ob
served data, the method of averages was used. This is described by Lipka (’18).
386 W. P. COVELL
 
Using the data on the transverse diameter of the fossa, Y
is then the diameter in millimeters, X is the crown-heel measurement in decimeters a11d a and I) are constants to be determined by this method. The following data given in the table
below are the observed values for total body length and for the
transverse diameter of the fossa.
 
 
CRowN_HEEL '1‘R.-\Ns\'ERSF. DIA.‘[lE”l‘F.R OF
 
THE 1-{YPOPH\‘s1-:.\l. 1-‘oss.\
Range Mean Mean
dm. rim. mm.
2.0 to 2.5 2.35 5.26
2.5 to 3.0 2.77 5.53
3.0 to 3.5 3.29 6.40
3.5 T0 -1.0 3.77 6.93
4.0 to 4.5 4.16 7.35
4.5 to 5.0 4.74 8.73
50 f0 3.5 5.31 9.90
 
From the above table it is obvious that the total body length
ranges from 2 to 5.5 dm. and includes six O.5—dm. intervals
with the mean of each interval equal to the sum of the body
lengths, for the individual cases, divided by the number of
cases falling within the interval. The corresponding average
for the transverse diameter was then determined for each
0.5—dm. interval. The averages for the diameter were then
proportioned so that about one—half of them would fall on
one side of an imaginary line and one—half on the other side,
as shown iii the following tabulation:
 
GIKOFP A GROUP B
 
Average body length (X) l Observed lnean tY) iAverage length (lX7),fl Observed mean (Y)
 
11 m. 7 mm.  dm.  mm.
2.35 ‘ 5.26 3.77  6.93
2.77 j 5.53 i 4.16 ‘ 7.35
3.29 l 6.40 1 4.74 8.75
 
l
 
32.93’ H
 
l
l
 
5.31  9.90
 
. _,, l , . . _ , ‘ . ,. ,
 
Total 8.41  17.19 ‘ 17.98 .
l
GROWTH or HUMAN PRENATAL HYPOPHYSIS 387
 
Averages for each group were summed and arranged ac—
cording to the formula: Y=aX+bn. Y is the total ob—
served averages in o11e of the groups, aX the sum of the total
observed averages of length times a and Mt is the number of
average points times I). If group A be arranged according
to the form of the expression, it will then read: 17.19 2 8.4151
+ 3b. Proceeding iii a similar manner with group B, the following expression is derived: 32.93 2: 17.9821 —l— 4b.
 
In order to solve for a and b, it is necessary to eliminate
one or the other. The 19 constant is the more readily removed
by finding the least common multiple for 3 a11d 4. This accom—
plished, the two equations are then subtracted, the smaller
from the larger, and the value of a determined.
 
17.19 :_— 8.41a + 3b 32.93 = 17.98a + 4b
or a11d or
68.76 = 33.64a + 121; 98.79 = 53.94a + 12b
 
98.79 : 53.94a + 12b
68.76 = 33.648 + 12b
 
36.03 = 20.30.21
21 =_a9;g3 : 1.48
20.30
 
Knowing the value of a, it is then easy to determine b by
substituting for a i11 one of the above equations.
 
17.19 =s.41(1.4s)+ 3b
3b : 17.19— 12.44, or 1) =4.75
 
3
b=1.58
 
Having obtained these constants, the numerical expression
of the transverse diameter of the fossa is the following:
Transverse diameter in mm. = 1.48 body length (dm.) -1- 1.58.
Values computed by means of this formula are to be found
i11 table 4.
 
ABSOLUTE GROWTH CHANGES
The growth i11 weight of the hypophysis and its lobes when
 
plotted against the body—length measurements (crown-rump
dimension used for the embryonic and early fetal life and
388 w. P. COVELL
 
crown—heel for the remainder of prenatal life) forms in each
instance a shallow curve witl1 an upper concavity. The data
represented by these curves may be represented approximately by means of the empirical formula: Y=aX". As
will be shown later, the growth of the pars nervosa of the
glaiid during the fetal life is the only data for weight of the
hypophysis which could not be approximated by the above
formula. The lineal determinations 011 the whole gland are
approximated by the straight—line formula: Y=aX+b.
The latter data include determinations 011 fetuses of 17) to
5.3 cm. in total body length.
 
The data dealing with the weight of the hypophysis in prenatal life have been separated into two parts and empirical
formulae derived for the expression of growth in each instance. Since the embryonic a11d early fetal material was
recorded in terms of the crown-rump measurement, certain
difficulties were encountered in trying to approximate this
period of growth with the same formula for the remaining‘
part of prenatal life. Embryonic (éliaiiges in growth are more
rapid than those for the fetal period, hence a more accurate
approximation of the growth changes in Volume were deduced
from a separate treatment of these data.
 
1. Lizzcal (linzcnsio-12.9‘ of flu‘ _(/Jami’.
 
The growth of the Various diameters of the gland in fetuses
1‘zt11g'i1)e; from 15 to 55 cm. in total body length is represented
in table 1 a11d figures 1, 2, and 3. The growtll of each of the
three diameters, which represent the maximum dimension of
the gland in the plane in wl1icl1 they were measured, may be
approximately expressed by means of a rectilinear formula.
Although the general character of growth is much the same
for each, the amount of growth appears to Vary. They will
thus be considered separately.
 
a. '1’rans*2rM'sc dianzdcr. The transverse diameter is the
largest of the three dimensions and represents the maximum
distance from one lateral side of the gland to the other. The
GROWTH or HUMAN PRENATAL HYPOPHYSIS 389
 
growth of the transverse dimension for this part of prenatal
life may be expressed by the formula:
Transverse diaineter of the liypopliysis ((-1n.) : 0.01178
[total body length (cm.)] + 0.1985.
 
Values computed by this formula for 5—em. intervals of
body length and compared with the observed averages for
the same intervals show a11 average absolute deviation of 0.024
cm. from the latter. The average percentage deviation of the
computed from the observed values is 3.89. According to the
values obtained by means of the formula, the transverse diam
TABLE 1
 
0l).S’€)'t'€(l and calculated ralucs of the diamcI.‘ers of the hypophysis in fetuses
rmzging in total body length from 15 to 55 cm.
 
 
 
M KAN ‘ 1{U\[]3 1.; 1;  2‘\q[‘1;I:‘]:1:E I I:\[)I;":‘l?;(I)(')R
CRE::§I(;1::;I4:L OF QASES 1 DIA.\u-‘.'1‘1-:R ‘
 
Observed Calculated ()bserved Caleillated Observed Calculated
cm. cm. cm om. rm. rm. cm. cm.
17.73 3 0.403 0.407 0.222 0.231 0.203 0.221
22.50 5 0.486 0.404 0.285 0.282 0.258 0.202
27.6.‘) 10 ()..");')3 (‘.524 0.330 0.337 0.339 0.307
32.74 13 0.610 0.584 0.390 0.302 0.406 0.350
37.46 12 0.630 0.63.‘) 0.446 0.443 0.390 0.390
42.67 8 0.675 0.701. 0.470 0.498 0.434 0.43.3
47.45 12 0.686 0.757 ‘ 0.526 0.550 0.386 0.476
52.62 13 0.822 0.818 0.307 0.605 0.492 0.519
 
 
eter of a hypophysis from a fetus measuring 15 cm. in length
is 0.375 cm. This increases to 0.493 cm. for a 25—cm. fetus,
0.611 cm. for one of 35 cm. and rises to 0.787 cm. in a 50-cm.
fetus.
 
It would thus appear from the above values that the transverse diameter of the gland increases about twofold between
the stages of 15 and 55 cm. of body length (erowirheel).
 
b. Antc:v)p0sterior (lianzmmr. The anteroposterior diameter
of the hypophysis is the second largest of the three diameters
and represents the maximum dimension of the gland from the
anterior to the posterior direction. Further, it is the only one
of the three diameters which involves the pars nervosa as well
as the anterior lobe.
390 W. P. COVELL
 
 
JDHI0I6i0Z(Z4Z6t‘d}01’}{J6)6404Z444640.705Z54}0Un
 
mi—Tr-r‘u—r‘1'1—rr1-1—Tr
 
     
 
'/94 /6 /6 Z0 Z5 Z4 Z6 Z5 )0 J8 J4 J6 13 40 48 44 46 46 50 J? 54 525cm.
 
Fig. 1 Field graph, with the curve of the empirical formula, of the growth
of the transverse diameter of the hypophysis in fetuses ranging from 15 to 55 cm.
(er0wn<heel). Abseissae: total body length in eentimeters. Ordinates: transverse diameter of the hypophysis in centimeters. Individual cases are indicated
by solid dots. Averages for 2.5-cm. intervals of body length indicated by circled
dots. Curve drawn to the empirical formula:
 
Transverse diameter of the hypophysis (em.) 2 0.01178
[total body length ((:m.)] + 0.1985.
GROWTH or HUMAN PRENATAL HYPOPHYSIS 391
 
The approximate growth of the anteroposterior diameter
may likewise be numerically expressed in terms of a straightline formula:
 
Anteroposterior diameter of the hypophysis (cm.) = 0.0107
[body length (cm.)] + 0.0408.
 
The average absolute departure of the computed from the
observed means for 5-em. intervals of body length is 0.015 cm.
The average percentage deviation of the same is approximately 3.4. The values obtained by means of the empirical
formula give the anteroposterior diameter as 0.20 cm. in a
fetus of 15 cm., 0.31 cm. for one of 25 cm. in length, and 0.41
cm. for one of 35 cm. in total body length. The anterior posterior diameter in a full-term fetus of 50 cm. is about 0.57 cm.
This dimension of the gland increases somewhat more than
the transverse diameter for the same intervals of prenatal
body length. The number of times which this dimension increases in fetuses measuring from 15 cm. and up to 55 cm.
is in the neighborhood of threefold.
 
(.’. Vertical diameter. The vertical diameter is the smallest
of the three diameters of the gland and represents the maximum dimension from its inferior surface to the junction of
the infundibular stalk with the main body of the hypophysis.
Since the infundibular stalk was severed at the junction with
 
the body of the gland, none of it is included in the measurements.
 
Fig. 2 Field graph and curve illustrating the growth of the hypophysis in
the anteroposterior diameter for fetuses ranging in total body length from 15 to
55 em. Abseissae: total body length in centimeters. Ordinates: anteroposterior
diameter in centimeters. Individual cases indicated by solid dots. Averages for
2.5—cm. intervals of body length indicated by circled dots. Curve drawn to
the formula:
 
Anteroposterior diameter of the hypophysis (cm.) = 0.0107
[body length (cm.)] + 0.0408.
 
Fig. 3 Field graph, with curve of the empirical formula, of the growth of the
vertical diameter of the hypophysis in fetuses ranging in total body length from
15 to 55 cm. Abscissae: body length in centimeters. Ordinates: vertical diameter of the hypophysis in centimeters. Individual cases represented by solid dots.
Averages for 2.5-em. intervals of total body length indicated by circled dots. Formula for the expression of the curve:
 
Vertical diameter of the hypophysis (em.) : 0.0085 [body length (cm.)] + 0.0705.
392 w. P. CovELL
 
The growth of this dimension of the gland may be approximately expressed by the simple empirical formula:
 
Vertical diameter of the hypophysis (('1n.) 2 0.0085 [body length (cm.)] + 00.0705.
 
The mean values calculated by means of this formula show
an average departure of 0.028 cm. from the observed means
for the corresponding 5—cm. intervals of body length. The
average deviation, in terms of per ee11t, is 7.74. VVhile this
figure exceeds the average percentage deviations of the other
two diameters, it is not too large to consider the formula a
fair approximation of the rate of growth of the hypophysis in
this diameter. The calculated vertical diameter of the gland
in a ].3—em. fetus is 0.19 cm., for a fetus of 25 cm. it is 0.28 cm.,
for one of 35 em., in total body length, it is 0.37 cm. In a
full-term fetus of 50 cm. in body measurement it is 0.49 cm.
 
The vertical diameter appears to increase in the neighl)01'hood of threefold from a fetus of 15—cm., erown—heel or total
 
».~—
 
body length, to one of 0;) cm.
 
2. Total 'm'igl2f of the gland
 
a. EnzIn'ym1i(? a/ml early fetal life. The growth in weight of
the hypophysis for part of prenatal life may be approximately
expressed by the empirical formula:
 
\V(-ight of the hypophysis (mg.) 2 0.022 (crown-rump ((-111.)”~“"‘).
 
Table 2 is a comparison of the observed with the calculated
data, while figure 4 is a shallow curve with the individual cases
and average points plotted.
 
The mean values obtained by means of this formula, for
25—mm. intervals of crown-rump measurement, when compared with the observed values for the corresponding intervals, show an average relative departure of 17.2 per cent.
The average absolute deviation from the observed average is
0.16 mg. The calculated weight of the gland for an embryo
of 10 mm. is 0.03 mg., for one of 50 mm. in length it is 1.01 mg.
The computed weight of the organ for a fetus of 100 mm.
(crown-rump) is 5.28 mg.
GROWTH or HUMAN PIIENATAL HYPOPHYSIS 393
 
It is obvious that the growth in weight of the gland for the
early part of prenatal life is exceedingly rapid. From the
above computed values the hypophysis may be said to increase
nearly 200 times in weight in material measuring from 10 mm.
to 100 mm. (crown-rump).
 
1). Fetal life (in f(>tuse3 [ranging from 15 to 55 ('m., fofal
body length. The growth of the hypophysis in weight during
the fetal period is illustrated in table 3 and figures 5 and 6.
V\/‘hen the individual Weights of the glands are plotted against
the cro\vn—heel measurements of the fetuses, a shallow concave
curve is formed. This curve may be expressed in approximate numerical terms by means of the empirical formula:
 
VVeight of the hypophysis (mg.) = 3.834 (body length (dn1.)“’“).
 
TABLE 2
 
Observed and calculated values for the weight of the whole gland and its lobes
in embzjw/(mic and early fetal life
 
_\n.~,AN V V \\'EIG 111' or THE WEIG}['l‘ or‘ THE \VElGH'l‘ or T}-IF. \\'El('iIl'I‘ 017' THE
CROV\'N~ NL"‘”f“ HYPOPHYSIS PARS AN’I‘ERI(1R PARS INTERMEDIA PARS NERVOSA
RCMP 01: ‘
LENGTH CASES
Observed (‘nlculzited Obsei-ve(l (‘alt-ulated Observed Calciilated Observed Calculated
mm. my. mg. mg. mg, mg. mg. mg. Wily.
11.0 1 0.0-1'1 0.028 0.032 0.030 . . . . .. 0.0005 0.001 0.0004
35.6 5 0.533 0.453 0.473 0.430 0.0169 0.0118 0.039 0.022
62.5 2. 2.094 1.725 1.800 1.542 0.0640 0.0532 0.170 0.144
87.6 3 3.653 3.838 33.866 3.313 0.1098 0.1313 0.410 0.441
 
The values calculated by this formula show an average
 
absolute deviation of 1.6 m0‘. from the corresponding observed
averages for 5—cm. intervals of body length. The percentage
deviation of the same is about 3. The range of the relative
departures of the calculated from the observed values is
+0.88 to + 6.8] per cent. The latter deviation falls Within
the interval of the crown-heel range of 20 to 25 em. The
relative deviation for the interval just preceding it is — 1.09
per cent, while the figure for the successive interval is + 0.88
per cent.
 
According to the above formula, the weight of the hypoph~
ysis is about 8.8 mg. in fetuses of 15 cm. (crown-heel), 25 mg.
394 W. P. COVELL
 
in 25-em. fetuses, 51 mg. i11 35-cm. fetuses, 86 mg. in 45—cm.
fetuses, and approximately 107 mg. in a full-term fetus of
50 em. in total body length. It is thus obvious that the approximate increase in weight of the hypophysis in a fetus of
15 cm. to one of full term is roughly eleven— or twelvefold.
 
Figure 6 is a shallow concave curve which illustrates tl1e
growth in weight of the gland during the fetal period in terms
of fetal or lunar months, the fetal age being determined from
the following formula developed by Seammon and Calkins
("23) :
 
T (age in fetal nio11tlI.<): 2.3 +/2.5L + L”
28 734
 
In the beginning of the fetal period the hypophysis weight
is approximately 5 mg. This value is doubled between the
fourth and the fifth months and increased fourfold by the end
of the fifth fetal month. By the beginning of the seventh
month, the computed weight has increased about tenfold. It
is thus about 50 mg. iii a fetus of the seventh fetal month.
During the ensuing three fetal months the hypophysis weight
increases even more rapidly. By the tenth month (birth), it
has increased about twe11ty- to twenty-twofold of the weight
at the beginning of the fetal period. It is thus obvious that
the gland increases in weight about tenfold between the third
a11d seventh fetal months and an equal amount between the
seventh month a11d birth.
 
Fig. -1 Field graph and curve of growth in weight of the hypophysis in embr_\'onic and early fetal life. Abscissae: ('l‘0Wl1-1‘1lll1p in millimeters. Ordinates:
weight of the hypophysis in milligrams. Individual cases indicated by solid dots
Averages for 25—mn1. intervals of (-1'own—rump intlieated by circled (lots. Curve
drawn to the empirical formula:
 
VVeight of the hypophysis (mg.) : 0.022 (erown—ru1np (c111.)“"‘”).
 
Fig. 5 Field graph and curve of the growth of the hypophysis in weight in
fetuses ranging from 13 to  em. in total body length. Abseissae: crown-heel
in centimeters. Ordinates: total weight of the hypophysis in milligrams. Individual cases indicated by solid dots. Averages for 2.5-eni. intervals of body
length indicated by circled (lots. Curve drawn to the empirical formula:
 
\Veight of the hypophysis (111g.) 2 3.834 (body length (dm.)”“"’“).
GROWTH OF HUMAN PRENATAL HYPOPHYSIS 395
 
5.5
1725.
5.0
4.5
4.0
15
10
 
Z5
 
Z0
 
 
/05
I00
 
JI4I6IdZ0t234£Oc‘dJ0J[}4J6}d404L‘44464d505c’545Ocm.
396 w. 1*. C()VELL
 
.5’. lVeig/It of the lobes of the gland
 
a. Emb1'y(mic aml early fetal life. Pars anterior. The
gro\\'tl1 clianges i11 weight for the pars anterior during embryonic and early fetal life resemble very closely the type of
changes whieli occur for the total gland weight of this time.
This is 11ot unusual, since the pars anterior comprises relatively more of the hypophysis in the early periods of (level
TABLE 3
 
()I;.wrz*ul mu! calculutw? values for the weiglzt of the whole gland and its parts
in f(’t1l.s‘e.s' rangizzg in fatal botly lengtlz from 15 to 55 cm.
 
u 1-:,\); \\'r:n:n'r or win: \VI<]lGH'l‘ or THE WEIGHT or THE wt-:|<:n'r 01-‘ THE
 
L-R0“-N. N(.M“ER }[Y1’()l’HYSIS PARS .-\N'r1-;R1oR PARS IN'rER.\nmIA PARS NF.R\‘()S.\
HWTIA or CASES
I‘ENG'T” (lhserved Cailculated Oliserved Calculated Ol>ser\'ed Calculated ()1-served (‘alculnted
cm. mg. my. my. ‘in g. 'n'I_(/. m 1/. 'm 1/. W1 g .
 
1.7.73 3 12.636 12.518 10.033 10.498 11.314 0.387 I 1.409 1.782
21.30 4 18.820 20.102 16.20.’; 16.613 0.566 0.561  10.49 .2 277
27.41 11 30.518 30.787 26.110 23.101 0.843 0.781 I 3.564 2.761
33.74 13 44.861 44.436 41.720 35i.8‘_’.6 1.084 1.039 5 5.1322 5.239
37.46 12 55.483 58.608 47.130 46.899 1.254 1.291 I 7.076 7.634
42.61 12 81.441 76.603 68.310 60.684 . 1.517 1.588  11.616 11.713
47.43 12 04.300 071.638 74.440 75.272 . 1.920 1.887 ‘ 14.680 16.960
.':.‘2.G‘_’ 17> 117.106 118.432 531.840 02.563 1.212 2.229 23.058 1 ‘35.591
 
opment than later. Table 2 and figure 7 illustrate the growth
of this part. It may be expressed numerically by means of
the empirical formula:
 
Weight of the pars anterior (mg.) 2 0.0242 (crown-rump (em.)“‘").
 
The average (liffereiice between the observed average
Values a11d those calculated by means of the formula for
25—mm. intervals of erown—heel measurement is 0.203 mg.
 
Fig. (3 Curve illustrating the weight of the hypophysis in terms of fetal
months. AlJS('lSSI1L‘: age in fetal months. Ordinates: weight of the hypopliysis
in milligrams.
 
Fig. 7 Field graph, with curve of empirit-al formula, of the growth in weight
of the pars anterior in embryonic and early fetal life. Ahseissae: crown»rump
in millimeters. Ordinates: weight of the pars anterior in milligrams. 'In(li\‘i(lual
vases indicaterl by solid dots. (llI'('l(’(l dots indicate average points for 2:3-mm.
i11t(-rvals of crown—rump. Curve drawn to the formula:
 
Weight of the pars anterior (mg.) = 0.01342 (crown-rump ((':m.)’-2°’).
GROWTH or HUMAN PRENATAL I-IYPOPIIYSIS 397
 
110
 
100
 
80
 
70
 
50
 
30
 
O ! I I I 1 1 s
3 4 5 O 7 6 9 10
Fetal months
 
 
.0 I0 20 J0 40 50 60 70 60 90 /00mm.
 
THE AMERICAN JOURNAL or AN.»\'l‘O.\fY, VOL. 38, NO. 3
398 W. P. C‘-OVELL
 
The largest of the absolute deviations of the calculated from
the observed values falls within the last two intervals of 50
to 100 mm. The relative differences are the largest in these
intervals. The average percentage deviation for the four
intervals of the body length is 12.1.
 
The values calculated from the above formula are as follows: For an embryo of 10 mm. the approximate weight of
the anterior lobe is 0.024 mg., for one of 50 mm. it is 0.929 mg.,
and about 4.09 mg. for a fetus of 100 mm. (cro\vn—rump). The
pars anterior of the hypophysis increases in weight from the
period under consideration about 200-fold. The growth i11
weight of the whole gland and the pars anterior are ver_v
nearl_v identical as regards the number of times which their
weiglit is doubled for the part of prenatal life.
 
Pars intermedia. Figure 8 illustrates, by means of a sl1al—
low curve, the changes which occur in the weight of the inter—
mediate lobe. The growth of the pars intermedia for the embryonic a11d early fetal life may be approximately expressed
by means of the empirical formula:
 
\\'eight of the pars intermedia (1ng.)=0.000393 (erown—run1p ((=111.)‘-’-‘““).
 
The calculated weight of this portion of the gland for an
embryo of 10 mm. (crown-rump) is approximately 0.0004 mg.:
in a11 embryo of 50 mm. it has increased to about 0.029 mg‘.;
tinally, in a fetus of about 100 mm. (crown—rump) it is approximately 0.187 mg.
 
Since the volumetric estimation of the pars intermedia is
(lifficult to determine in an embryo of 11 mm., only the calculated weight is given for the first interval. The other three
intervals of crown—rump up to 100 mm. show a relatively high
departure of the observed from the calculated values. These
are probably of very little significaiice, since the pars intermedia is small and obviously the most difficult. of the lobes to
determine volumetrically. The computed values are only a
rough approximation of the growth changes in weight for this
part of the gland in early intra—uterine life.
GROWTH or HUMAN PRENATAL HYPOPHYSIS 399
 
Pars nervosa. Figure 9 and table 2 illustrate the growth of
the pars nervosa in embryonic and early fetal life. It differs
from the type of growth of the other two lobes by the fact
that it appears later in embryonic life and increases at a
comparatively slow rate up to a certain point, from which
time on it increases rapidly. The empirical formula derived
for the approximate expression of its growth is:
 
Weight of the pars nervosa (mg.) =0.000335 ((‘1'0w11-1'1lmp (ozn.)“4“"’).
 
The average relative deviation of the observed from the
computed values for 25—mm. intervals of crown—rump is about
22 per cent. The average absolute deviation for the same is
about 0.02;’) mg. The computed weight of this part of the
hypophysis iii an embryo of 10 mm. is 0.0003 mg.; in an embryo of about 25 mm. this weight has increased to 0.007 mg.;
in one of 50 mm. the approximate weight. is 0.068 mg., and
finally in a specimen of 100 mm., crown-rump, it is about 0.68
mg. It is thus obvious that the weight increases about 100fold from the stages of a 25-mm. embryo to a fetus of 100 mm.
 
1). Fetal life (in fetuses rai/aging from 15 to 55 cm., total
body Zen;/tie). Pars anterior. The changes in weight of the
pars anterior are shown in table 3 and illustrated in figure 10.
This portion of the gland appears to grow in a manner similar
to that of the total gland weight. Such a similarity in the
two curves is expected, since the pars anterior comprises the
larger portion of the total gland volume. The empirical formula for the approximate expression of the shallow concave
curve is as follows:
 
\‘\‘'eight of the pars anterior (mg.) = 3.338 (body length (dm.)"-'-""‘).
 
VVhen the calculated values are compared with the observed
averages for 5—cm. intervals of body length, the average (leparture of the former from the latter is roughly 2.1 mg. The
average relative deviation of the same is 4.75 per cent. The
range of the relative deviations of the calculated from the
observed values is -4- 0.78 to ~—14.14 per cent. The larger
deviation is for the crow11—heel interval of 30 to 35 cm. It is
400 W. P. COVELL
 
negative and is preceded and also followed by negative departures of much smaller significance. There is also a negative deviation of 11.17 per cent for the body-length interval
of 40 to 4.5 cm. This, however, is preceded by a negative
deviation of 0.53 per cent, a11d a positive deviation of 1.11
per cent for the succeeding interval. It is thus apparent that
the differences of the calculated from the observed values are
in fair agreement.
 
The weight of the pars anterior as computed for a fetus of
15 cm. (crown-heel) is about 7.6 mg., for one of 25 cm. it is
21.1 mg., for a 45—cm. fetus the weight of the pars anterior
is 68.4 mg., and for a full—term fetus of 50 cm. it is approximately 83.4 mg. It is obvious that the weight of the pars anterior increases about elevenfold from a fetus of 15 cm. to
one of full term.
 
Pars intermedia. The growth of the pars intermedia is
illustrated in figure 11 and table 3. When the weights of this
portion of the gland are plotted against the body length
(crown-heel) of the fetus, a shallow curve is formed which
closely resembles that described for total gland weight and
weight of the pars anterior. It may be approximated, numerically by the following empirical formula:
 
Weight of the pars intermedia (mg.) : 0.1544 (body length (dni.)"“°3).
 
Values obtained by means of this formula show an average
absolute departure of 0.043 mg. from the observed averages
 
Fig. 8 Field graph and curve of the growth in weight of the pars intermedia
in material ranging from 10 to 100 mm., (-.rown—rump. Abseissae: erown—rump in
millimeters. Ordinates: weight of the pars intermedia in milligrams. Individual eases indicated by solid dots. Cirt-led (lots indicate averages for 25-min.
intervals of crown-rump. Formula for the expression of growth in weight:
 
\Veight of the pars intermedia (mg.) =0.000393 (crown-rump (cm.)““").
 
Fig. 9 Field graph and curve illustrating the growth in weight of the pars
nervosa in material ranging from 10 to 100 millimeters, crown—rump. Abseissae:
(-rown-rump in millimeters. Ordinates: weight of the pars nervosa in milligrams.
lndi\'i<lual cases in solid dots. Averages for 25—mm. intervals of erown-rump
indicated by circled dots. Curve drawn to the formula:
 
Weight of the pars nervosa (mg.) =0.00().-‘$35 (crown-rump ((*111.)““").
GROWTH OF HUMAN PRENATAL HYPOPHYSIS
 
 
0]0ZOJ0405000708090}00mm.
 
 
 
3 1.‘
0 /0 Z0 }0 40 50 D0 70 50 90 ]00I7}I‘n
 
401
402 w. P. COVELL
 
for the corresponding C)—cm. intervals of total body length.
The average relative deviation of the same is 6.71 per cent.
The largest individual percentage deviation of the calculated
from the observed values falls within the interval of total
body length with a range of 15 to 20 cm. It is + 23.25 per cent
and is followed by a departure of ——8.83 per cent. The six
remaining relative deviations are all below 7.5 per cent. Three
of these are positive and three are negative. The smallest
departures for the relative differences are for the newborn
material.
 
The computed weight of the pars intermedia is approximately 029 mg. in a 15-cm. fetus, 0.67 mg. iii a 25—cm. fetus,
1.73 mg. in a 45—cm. fetus, and 2.05 mg. for a full—term fetus
(50 cm.).
 
Pars nervosa. The growth in weight of the pars nervosa
of the hypophysis is shown in table 3 and illustrated in figure
12. VVhen the weight of this part of the gland is plotted
against the body length of the fetus, a shallow concave curve
is formed which may be approximated by the formula:
 
\Veight of the pars nervosa (mg.) : 0.384 (e 0.798 body length (dm-l).
 
This curve shows a gradual increase in weight of the pars
nervosa up until 35 cm., and a more rapid rise from then 011.
The values computed by means of this formula show an
average absolute deviation of 0.837 mg. from the corresponding observed averages for ;')—em. intervals of body length.
 
Fig. 10 Field graph and curve illustrating the growth in weight of the pars
anterior in fetuses ranging from 15 to 55 cm., erown—hcel. Abscissae: crown~hee.l
in centimeters. Ordinates: weight of the pars anterior in milligrams. Individual
observations indicated by solid dots. Circled dots indicate averages for 2.5-(-in.
intervals of total body length. Curve drawn to the formula:
 
Weight of the pars anterior (mg) = 3.338 (body length (dm.)““‘).
 
Fig. 11 Field graph and curve of the growth in weight of the pars intermedia
in fetuses ranging from 15 to 55 cm. in total body length. Abscissac: body
length in centimeters. Ordinates: weight of the pars intermedia in milligrams.
Individual observations indicated by solid dots. Cireled dots indicate averages for
2.5-cm. intervals of body length. Curve drawn to the empirical formula:
 
Weight of the pars intermedia (mg.) = 0.1544 (body length (dm.)‘-""").
GROWTH OF HUMAN PRENATAL HYPOPHYSIS 403
 
8
7
6
 
.5
 
.4
)
Z
I
 
/4/o to 202224 2o 2oJo12)4J¢x4a42444am 5052 54,5érm
404 W. P. COVELL
 
The average percentage deviation of the calculated from the
observed values is 10.16 per cent. The range of the relative
deviations is from 0.88 to 22.53 per cent. The largest relative
difference falls within the body—length interval of 25 to 30 cm.
It is, however, preceded by a positive deviation of 11.13 per
cent and followed by a positive deviation of 3.26 per cent.
The computed values appear to be closest in their agreement
with the observed values between the intervals of 30 to 45 cm.
(crown—heel ).
 
According to the above formula, the weight of the pars
nervosa in a 15—cm. fetus is 1.26 mg., in one of 25 cm. it is
about 2.82 mg., in a 45—em. fetus it is 13.87 mg., and 20.7 mg. in
a full-term fetus of 50 em. in total body length. It is thus
obvious that the posterior lobe increases about sixteenfold
from a 15-cm. fetus to one of full term.
 
4. Lineal dime/nsio/ns of the hypophyseal fossa
 
The growth of the hypophyseal fossa in the transverse,
anteroposterior, and vertical diameters is illustrated in table
4 and figures 13, 14, and 15. The hypophyseal fossa is usually
larger transversely than in the other diameters. The anteroposterior diameter is second i11 size, while the vertical diam
Fig. 12 Field graph and curve of the growth in weight of the pars nervosa in
the fetal period. Abseissae: body length in centimeters. Ordinates: weight of
the pars nervosa in milligrams. Individual eases represented by solid dots. Cireled dots indicate averages for 2.5-em. intervals of body length. Curve drawn
to the formula:
 
Weight of the pars anterior (mg.) = 0.0242 (crowlfi-rump (cin.)2-267).
 
Fig. 13 Field graph and curve of the growth of the transverse diameter of
the hypophyseal fossa in fetuses ranging from 20 to 55 cm. in total body length.
Abseissae: body length in centimeters. Individual cases indicated by solid dots.
Ordinatesz transverse diameter of the fossa in centimeters. Averages for 5-em.
intervals of body length indicated by circled dots. Curve drawn to the formula:
 
Transverse diameter of the hypophyseal fossa (cm.) :1.43
[body length (dn1.)] + 1.73.
 
Fig. 14 Field graph and curve of the anteroposterior diameter of the hypophyseal fossa in fetuses ranging from 20 to 55 cm. in total body length. Abscissae: body length in centimeters. Ordinates: diameter of the fossa i11 eenti«
meters. Individual cases indicated by solid dots. Cireled dots indicate averages
for 5-cm. intervals of body length. Curve drawn to the formula:
 
Anteroposterior diameter ((-m.) = 0.592 body length (d1n.) + 2.41.
.70
.05
.00
.55
.50
.45
.40
 
.35
.5
 
GROWTH OF HUMAN PRENATAL HYPOPI-IYSIS 405
 
 
 
(7
6
4
5 vs.
014/1: /a i|0Z;2-l1_Z|éz“4l5f§(1_3l£-31-¢.4+0fl!*<1  4a 50 52 54 Jacm
I./5
C77).
I./U
/.0}
/.00
.95
.90
.05
.50
.7}
.70
.05
.60
.55
.50
 
‘45
 
‘4%ozaz4:ozax2)zJ4)o1a4o4z444o4a5o25450:».
 
 
. 75
cm.
 
0&0 Z6 Z4 Z6 Z6 )0 J3 54- J6 36 40 42 44 46 46 f0 55 54 56cm.
406 w. P. COVELL
 
eter is the least of three. The transverse diameter represents the maximum distance between the lateral extremities
of the fossa. The anteroposterior diameter is the distance
between the anterior surface of the dorsum sellae and the
posterior border of the tuberculum sellae. The vertical dia 1.eter is the distance from an imaginary midpoint on the anterior posterior diameter to the floor of the fossa. The growth
of the three diameters may be approximated by means of
straight-line formulae. Since there are certain peculiarities
individual to each, they will be considered separately.
 
TABLE 4
 
()I)serve(l and calculated values of the diameters of the hypophg/seal fvssa in
fetuses 1'a¢1ging in. total ‘I)ody-l€7:gth from 20 to 5.5
 
 
'l‘RANS\’ERSE ANTI-2R0-Pos'rERIOR vi-:m‘IcAI.
"BAN xunmm I)IAME’I‘ER mA.\n~:'ri:R 1>IA.\n«:'1*nR
”“‘).:“;1:’(;I,I{,I“‘IEI‘ OF CASES
Observed Calculated Observed (‘aleulated Observed Calculated
cm. rem. om. rm. cm. cm. cm.
 
23.46 5 0.526 0.500 0.380 0.380 0.200 0.200
27.73 3 0.533 0.563 0.373 0.405 0.187 } 0.214
32.89 10 0.640 0.639 0.467 0.437 0.258 1 0.232
37.67 8 0.093 0.711 0.457 0.464 0.235 0.248
41.68 5 0.735 0.769 0.476 0.487 0.248 0.262
47.35 12 0.875 0.853 0.486 0.521 0.280 0.281
53.08 7 0.990 0.938 0.622 0.55.’) 0.341 0.301
 
 
a. Transverse diameter. The growth of the transverse
diameter in fetuses ranging from 20 to 55 em. in total body
 
length may be approximately expressed by the empirical formula:
 
Transverse diameter (mm.) = 1.43 [body length ((lm.)] + 1.73.
 
The values obtained by means of the formula and compared
with the observed values for the corresponding 5—cm. intervals of body length show an average absolute departure from
the latter of 0.024 cm. The average percentage deviation of
the same is 3.25.
GROWTH or HUMAN PRENATAL HYPOPHYSIS 407
 
1). Amteropostelrior‘ diameter. The growth in the a11tero—
 
posterior diameter may be expressed by the formula:
Anteroposterior diameter (mm.) -—-0.592 [body length (dm.)] + 2.41.
 
The mean percentage deviation of the calculated from the
observed values is 5.32 and the absolute deviation is 0.026 cm.
 
0. Vertical diameter. The changes in growth of the depth
of the hypophyseal fossa may be approximated by means ofi
a straight-line formula:
 
Vertical diameter (mm.) =0.343 (body length (dm.)) + 1.191.
 
TABLE 5
 
The 7'elat2't'e volume of the lobes of the hypophysis for material between
11 and J00 mm. (crown-rump)
 
   
   
 
       
   
     
 
RELATIVE VOLUME RELATIVE VOLUME RELATIVE VOLUME
CASE NO. CRO\\'N-HUMP OF PARS OF PARS OF PARS
ANTERIOR IN'l‘l<‘.RMEDIA NERVOSA
Per cent 1’I'r (rent
98.35 . . .. 1.65
91.60 2.59 5.81
89.03 3.37 7.60
86.45 4.41 9.14
88.46 3.03 8.51
90.28 3.19 6.53
88.26 3.08 8.66
87.17 3.20 9.63
84.24 3.96 11.80
86.05 2.11 11.84
 
The average mean departure of the calculated values for
;')—cm. intervals of total body length from the observed values
for the same measurements of body length is about 0.017 cm.
The absolute mean deviation for the above is 6.82 per cent.
 
The range of the relative differencesis from 0 to 14.44 per
cent.
 
RELATIVE GROWTH CHANGES
 
The relative volumes of the lobes of the hypophysis are
shown in tables 5 and 6 and figure 16. The relative volume
of each lobe appears to change as the fetus approaches the
408
 
W. P. COVELL
 
TABLE 6
 
Relative volumes of the lobes of the hypophg/sis in fetuses ranging from about
90 to 55 cm. in total body length (twenty-nine cases)
 
CASE NO.
 
FP5
FP-1
FP7
 
M01111
 
Case 3
2~1——165
FF 2
1727
1732
 
M02111
 
24-25
FP 1
24-796
1744
 
M ea 11
 
24-24
23-849
1737
 
M ezm
 
25-17
1766
24-559
22-—323
 
Mean
 
23-409
24-795
23-224
 
Mean
 
3531
1746
1765
1735
23-840
24-251
24~60
 
Mean
 
1
1
1
 
TOTAL BODY
 
1RELATIVE VOLUME
‘ 01‘ THE PARS
 
OF THE PARS
 
msnmxvm VOLUME 1RELA'I‘IVE voLL'.\1n
01‘ THE PARS 1
 
LENGTH 1 ANTERIOR INTERMEDIA 1 NERVOSA
1 1
cm. 1 Prr vent PP?’ vent  Per cm!‘
21.5 85.46 3.02 12.42
22.2 1 87.51 2.90 1 9.59
25.4 1 86.25 3.09  10.66
1 86.11 1 3.00 1 10.89
27.0 1 85.50 1 2.74 1 11.76
28.0 1 87.50 ‘ 2.46 1 10.04
29.2 1 85.91 2.33 1 11.76
29.5 1 81.15 1 3.35 1 15.50
30.0 1 86.91 1 2.63 1 10 46
__ 1.“- 1  .1- __
1 85.40 1 2.70 1 11.90
1 1
31.0 1 85.61 2.77 1 11.62
34.3 1 87.32 1.77 ‘1 10.91
35.0 1 85.89 1 2.09 1 12.02
35.2 1 85.70 1 2.30 12.00
1 86.13 1 2.23 1 11.64
1
38.0 83.60  2.15 1 14.25
39.0 85.80 1 1.70 1 12.50
40.0 84.94 1 2.95 1 12.11
84.78 1 2.27  12.93
41.3 82.57 1.98  15.45
42.0 86.06 1.76 1 12.18
42.5 83.21 2.29  14.50
45.0 84.59 1.45 1 13.96
1 83.86 1.86 1 14.38
1
46.0 77.53 1.66 1 20.81
45.5 78.33 1 2.82 18.85
49.0 80.00 1 - 1.70 1 18.30
1 78.62 2.06 1 19.32
50.7 77.82 2.65 19.53
51.5 70.05 1 2.14 1 27.81
51.5 78.71 ‘ 1.82 1 19.47
51.0 78.78 1.22 1 20.00
54.0 82.26  1.54 1 16.20
54.5 84.13 1 1.67 14.20
55.0 77.22 2.22 20.56
78.42 1.89 1 19.69
GROWTH or HUMAN PRENATAL HYPOPHYSIS 4.09
 
tenth lunar month. The pars anterior comprises relatively
more of the hypophysis in the embryonic and early fetal
stages than it does later in prenatal life. The pars intermedia
 
 
 
5 /5 [5 .55 45 55 cm.
 
1%)": /Yen/osa Ear: /n/e/‘media Ram/Fnferlbr
 
.45
.40
. 35
.50
.85
. E0
 
./5
 
JOZO Z3 Z4 Z6 [:3 J0 J2 J4 J6 56 40 4E 44 46 40 50 52 54 56cm
 
 
Fig. 15 Field graph and curve of the vertical diameter of the hypophyseal fossa
in fetuses ranging from 20 to 55 cm. in total body length. Abseissae: total body
length in centimeters. Ordinates: vertical diameter of the fossa in centimeters.
Individual eases indicated by solid dots. Circ-led dots indicate averages for 5~c1n.
intervals of body length. Curve drawn to the empirical formula:
 
Vertical diameter of the fossa (em.) = 0.343 body length (dm.) + 1.91.
Fig. 16 A histogram representing the changes in the relative volumes of the
 
three lobes of the hypophysis. The base line is marked off into 10~em. intervals
of body length. The total gland volume for each interval is 100 per cent.
410 w. P. covELL
 
likewise comprises relatively more of the gland volume for
the early part of intrauterine life. The pars nervosa apparently makes up less of the gland volume early in its fetal
development than it does later.
 
Figure 16 illustrates the relative volumes of each of the
lobes for 10—cm. intervals of body length from 5 to 55 cm. In
fetuses of 5 to 15 em. (crown-heel) the anterior lobe comprises
about 87.7 per cent of t.he total gland volume, the remainder
of the volume is 3.16 per cent pars intermedia and 9.14 per
cent pars nervosa. The relative volume of each part of the
gland in fetuses of 15 to 25 cm. total body length is slightl_v
changed. I11 this interval the pars anterior is 86.21 per cent,
the pars intermedia is 2.78 per cent, and the pars nervosa is
11.01 per cent. From 25 to 35 cm. (crown—heel) the anterior
lobe forms 85.78 per cent, the pars intermedia 2.58 per cent,
and the posterior lobe (pars nervosa) about 11.64 per cent.
In fetuses of 35 to 45 cm. in total body length the anterior
lobe may be said to comprise about 84.56 per cent of the total
gland volume; of the remaining 15.44 per cent, 2.07 per cent
is pars intermedia and 13.37 per cent is pars nervosa. The
most noticeable change in relative volumes appears to occur in
the latter part of the fetal period. For the interval of 45 to
55 cm. the anterior lobe comprises about 78.62 per cent, the
pars intermedia about 1.91 per cent, and the pars nervosa
19.47 per cent.
 
Table 5 gives the relative volumes of the lobes of the gland
in embryonic and early fetal material. Table 6 gives the observed relative volumes and their averages for 5-cm. intervals
of total body length. This is the arrangement of the observed
relative values used for determining the approximate weight
of the lobes of the hypophysis for the fetal series. VVhile
these percentage values are only approximations, it is nevertheless evident that the three different lobes do 11ot maintain
 
the same rate of growth throughout the embryonic and fetal
periods.
GROWTH or HUMAN PRENATAL HYPOPHYSIS 411
 
Relative litnlcreagse in the growth of the hypophysis, its lobes
rmd the hiypophyseal fossa
 
The relative increase which occurs iii the hypophysis during
the embryonic and early fetal life will be considered first. The
amount of relative increase for this part of prenatal life is
given in table 7 and figures 17 and 18. The weights of the
gland and also of each of the three lobes are considered as
being equivalent to 100 per cent in a fetus of 100 mm. (crown—
rump). These data have been computed separately, because
the early growth changes are different from the later.
 
TABLE 7
 
Weigltt of the hypophg/si.s' and its lobes -in (fmbryonic and early fetal lift! ('(lI('lI—
lated in percentages of them‘ weights in CL fetus of 100 mm. (crowmrmnp)
 
CR0“.N,Rmu, W1-:1(;.H'r 01:‘ 'rH1~; \\'EIGll’l‘ or THE \\'EIGH'I‘ on THE \\'I~:lG}{'1‘ OF THE
GLAND PARS AN'I‘l-‘.RI()R PARS INTERMEDIA PARS NEKVOSA
mm. Per cent Per cent
10 0.37 0.10
30 3.93 1.90
50 ; 15.60 10.10
70 , 38.46 30.60
00 l 75.32 70.42
 
100 100.00 100.00
 
 
The total weight of the gland increases rather gradually
to about 50 mm. (crown-rump), after which time it appears
to rise more rapidly. The volume of the gland in an embryo
of 50 mm. is roughly about one—fifth of the volume of the gland
in a fetus of 100 mm. (crown—ruInp).
 
The pars anterior shows a relative increase very much
similar to that for total gland weight. The curve of growth
is more concave for 10 to 50 mm., after which time it rises
rapidly to 100 mm. Here, again, the volume in a :30-mm. embryo is approximately one—fifth of the total weight in a fetus
of 100 mm. (crown—rump). A
 
The pars intermedia apparently undergoes a similar rate of
growth in these early stages. In an embryo of 50 mm. it
represents about 15 per cent of the volume which it finally
attains in a fetus of 100 mm.
412 W. P. COVELL
 
700
 
90
 
60
 
70
 
(70
 
50
 
40
 
JO
 
[0
 
 
   
 
0 o :0 J0 40 50 so 70 60 90 /00mm.
 
—- /‘bra /ntermedia
—— Rzra /Inferior
 
 
o /0 80 J0 40 I0 00 70 00 90 100mm.
 
Fig. 17 Curve illustrating the growth in weight of the hypophysis in the
enibryonic and early fetal periods, computed in percentage values of the weight in
21 fetus of 100 mm., crown—rump. Abseissae: er0wn~rump in millimeters. Ordinates: per cents of values in a fetus of 100 millimeters, crown-rump.
 
Fig. 18 Curves illustrating the growth in weight of the lobes of the liypoph»
ysis, in cnibryonic and early fetal material, computed in terms of the value in
a fetus of 100 millimeters, cr0wn—rump. Abscissae: cr0wn—rump ‘m millimeters.
Ordinatos: per eents of the value in a fetus of 100 millimeters, crown-rump.
GROWTH or HUMAN PRENATAL HYPOPHYSIS 413
 
The pars nervosa undergoes a much slower rate of growth
in the earliest stages, but rises rapidly from 70 to 100 mm. In
figure 18 it is obvious that the volume of the posterior lobe in
an embryo of 50 mm. is only about 10 per cent of the volume
of that part of the gland in a. 100—mm. fetus.
 
Changes in relative increase dmmg fetal life
 
The weights of the hypophysis and its lobes calculated in
terms of per cent of their weight at birth are shown in table 8
and figures 19 and 20.
 
TABLE 8
 
Weight of the hypnphysis and its lobes calculated in percentages of their
weights at birth (50.2 cm., total body length)
 
VVEIGHT OF THE 1 ‘\\'EIGH'l‘ OF THE
PARS ANTERIOR PARS NERVO SA
 
TOTAL BODY
LENGTH
 
WEIG KT OF THE
HYPOPHYSIS
 
l 4
 
l l
cm. 1 Per cent t Pm‘ renf  Per cent
15 t 8.23 8.91 .| 6.09
25 l 23.69 22.61 I 13.62
35 4 47.44 48.62 g 30.29
45 l 77.69 80.27 ] 67.00
50.2 ‘ 100.00 100.00 3 100.00
 
I
 
The total gland Weight in a fetus measuring 15 cm. (crownheel) represents about one-twelfth of the Weight of the gland
at birth. In a 25—cm. fetus the gland volume is approximately
one—fourth of the weight which it attains by the time of birth.
The gland of a 35-cm; fetus may be said to comprise about
one-half of the hypophysis weight of a fetus of 50 cm. (crownheel). From the above facts it is obvious that the most rapid
increase in relative volume occurs in fetuses ranging in total
body length from 35 to 50 cm.
 
The pars anterior and pars intermedia are quite similar
to the total gland weight in the amount and distribution of
the relative increase. This statement is especially true of
the pars anterior, which comprises by far the bulk of the
gland. In a fetus of 15 cm. (total body length) the pars a11
 
 
 
 
/00
 
90
 
70
 
50
 
40 1
 
JO
 
[0
 
I9
/0 /5 20 :5 J0 )5 4o 45 50 55cm.
 
4
 
—- Pars /rflz:/77edia
I " "‘ Pars; /‘in terio/‘
 
"'-' Pans /‘/pr vosa
_j_§___
I
i
 
 
/0 If Z0 (5 I0 17 /I0 /7 5 50 5%/v».
 
Pig’. 1!! (‘urw illustrating" the }.I:mw‘rl1 in wt-iglxf of the h§'1m]»l1.\'..s'i.s' in f<-tum-s
r;u:;_{i11;;' frmn 1.’: to 37: rm. in total l>ml}' lmlgtll (‘(lHl])11Tl*[l in T(‘I'l1)S of H10 \':11u«~
:11 lrirth. AI)S(‘i.\‘S2((‘2 lm(l_\' 14-ngth in m-I1tiI1wh‘1‘,s*. ()1'di11at<*.\': In-1' cmlfs of flu»
Vuluv :11 luirth.
 
Fig". 21) (‘111'\'vs ilIush‘:lting' flu‘ g'1'm\"(l1 in weight «If 1111- lulws of the }1_\'[mph_\'.\‘i.<
c-mnpuh-(1 in tor111>' of Hwir \':\Iuvs at birth. A])sriss.‘l1‘: <-1'm\'n—h('vl in 1-mlfivlwh-1's
()1-<lin:m-,<: pm‘ ('(‘1H‘S of tlw \':1I\u- of thu \\'('i;_rM at birth.
 
 
 
 
terior represents approximately one—twelfth of the Volume of
the anterior lobe of a 50—cm. fetus, whereas the pars inter—
media in a 15—em. fetus is about one—seventh of the Volume of
the pars intermedia of a newborn. The latter estimate is
slightly more than the relative Volume determined in per
cent‘ of the gland weight and weight of the anterior lobe for
the newborn.
 
The pars nervosa appears to grow differently from either
of the other two parts or the total gland weight. The Weight
of the pa.rs nervosa at birth is approximately sixteen times
g1‘eatei' than the weight of this portion of the gland iii a fetus
 
TABLE 9
 
Lincal (Iimem-ions of the Ii_2/poplzg/.s-i.s~ computed in ymrcentages of their values
at birth (.50.? cm., iotal body len_(/th)
 
H ,_ V _  'l‘RANS\'ERSl<2 .\N'ri:Ro-rosT1—:i:Iok \'i:Ic'rIC.\L
 
'0'” BM" I'EM'”I DIAMF/r1-Ir. 1)[.\METER DIA.\IE'J‘1~1R
cm. Pm‘ wen! Per cent P13!‘ We'll’,
1;‘) 47.58 34.89 39.84
23 62.47 53.37 56.94
33 77.35 71.83 74.04
43 9.‘3.2»l 90.33 91.13
30.2 ](l0.(N) l0l7.()0 100.00
 
of 15 em. (crown-heel). The most marked increase for this
lobe begins to occur at 35 cm., erown—heel length, and by the
time of birth it has increased nearly threefold in Volume.
 
H«'I(Ifirw z'1zm'('a.w' in lineal rlinwizsirnm
 
Table SD gives the lineal dimensions of the l1_Vpopl1ysis eom—
puted in percentages of their size at birth. The anteropos—
terior and Vertical diameters are approximatelv one—third as
large as the same diameters of the l1_\'popli_\'sis of the ilexvborn.
The trans\'erse diameter of the gland in a 25«0m. fetus repre—
sents about two-tliirds or less of the same lineal dimension
of the liypopliysis of a newborn. The anteroposterior and
\'e1'tieal diameters for the same ag‘e are slightly more than
one—half of the two diameters of the full—term fetus. The
416 W. P. COVELL
 
transverse diameter of a fetus measuring 35 em., in total
body length, is about three—fourths of the same diameter in
the newborn. The anteroposterior and vertical diameters
closely approximate the same relative values as the transverse
diameter of a 35-cm. fetus. In a fetus of 45 cm. (crown—heel)
 
the diameters of the gland are about one—tenth less than the
same diameters for a full—term fetus.
 
----- -- Hvpoptwysu unfit
———— Para newoaa weigh!
Total body might
-—--— Eyeball volume
—- — Optic new volume
~— —- Cerebrum volume
-—-—~ Cxmbcllumvolumc
—— -- l‘1ldbf5ll’1VDl|-NT‘-C
—- - ‘Pon: and mcdulh wlurm
----- i - 5pmal cord volume
 
 
Fig. 21 Curves illustrating the fetal growth of the total body weight, the
volumes of the various parts of the brain, the spinal cord, optic apparatus, and
the weights of the hypophysis and pars nervosa. The values have been reduced to
a common scale by dividing the absolute values for 5—em. intervals of body length
by the weight or volume at birth. Abseissae: total body length in centimeters.
Ordinates: per cent of the value at birth.
 
I1’('lafi1>(% 2"I2(:r(?a3(: in the livzcal (Iim(371.3i012.s of the hypoplzyseal
fossa
 
The relative increase of the various diameters of the hypophyseal fossa computed in terms of per cent of their size at
birth are shown in table 10.
 
A glance at the three columns of figures representing the
percentage values of each diameter shows that in a fetus
GROWTH or HUMAN PRENATAL HYPOPHYSIS 417
 
of 20 cm. (crown—heel) the various diameters are from onehalf to two—thirds of the size which they attain in a full—term
fetus. The transverse diameter increases at the rate of about
8 per cent for each 5—cm. interval of body length from 20 to
50 cm. It is thus about three-fourths of the size in a 35-cm.
fetus of what it is in a full-term fetus.
 
The anteroposterior diameter, the second largest of the
three diameters, represents about two—thirds in a 20-cm. fetus
 
TABLE 10
 
Lincal dimensions of the hypophyseal fossa computed in percentages of their
size at birth (50.2 cm., total body length)
 
TRANSVERSE
DIAMETER
 
VERTICAL
DIAMETER.
 
ANTERO-POSTERIOR
 
TOTAL BODY LENGTH DIAMETER
 
I
 
I
 
I
cm. PM cent W7 Per cent Per cent
20 51.52 66.73 64.50
25 59.48 72.30 70.38
30 67.56 35 75.53 E 83.27 82.13
40 83.61 I 88.85 87.97
45 91.58 94.24 93.81
 
N
9
l
77.69  76.29
t
; 100.00
 
50.2 100.00  100.00
 
 
 
of the same diameter of the fossa in a full-term fetus. It increases at the rate of about 4 to 6 per cent for each 5—cm.
interval of body length from 20 to 50 cm. In a fetus of 35 cm.
the diameter is a little more than four—fifths of that in a 50—cm.
fetus.
 
The vertical diameter of the fossa is the least of the three
diameters, but shows a similar increase in relative size to that
of the anteroposterior diameter. In a fetus of 20 cm. it is
slightly less than two—thirds of its approximate size at birth.
It also increases at the rate of about 4 to 6 per cent for each
5—cm. interval of body length.
 
 
 
,1 mmpa,ri.swn of the fetal growth, of H/(1 Izgz/p0pl2y.s*i.s' with that
of ()HI(’I‘ organs‘ and total body 1r("iK(/In‘
 
It has been shown i11 figures 4, 5, and T to 12 (inelu_si\'e)
that the fetal g.>;rowtl1 in wei;:;lit of tlie hypophysis and its
lobes when plotted against the total body length follow tl1e
course of a shallow concave curve. It is obvious that the
partes anterior and intermedia approximate more closely the
;:eneral type of growth of the total gland weigllt than does
the pars nervosa. The latter presents a greater eoneayity to
its curve.
 
Figiire 21 shows the percentage growth of the liypopllysis
weigllt a11d the weight of the pars neryosa which are plotted
on the same graph with Volumes of fetal brain parts, as determined by Dunn (’21), optic apparatus (Seammon and Armstrong, ’25) and total body weiglit (Seammon a11d (‘alkius,
’23). lt is evident that the hypophysis follows the general
type of curve characteristic of the fetal growth in weight of
the whole body as well as the volume of its parts.
 
The clianges in the growth of the gland as a whole approximate the growth of the Volumes of the eyeball, midbrain, and
spi11al cord more closely than the other gzrowth euryes. The
most outstanding <lift'ere11ee between the curve for growth of
the hypopliysis and these curves is the age at which it l)egi1is
to show the most. rapid increase. (It is somewhat earlier, being‘
apparent at about the body—leng'th measurement of 25 em.,
whereas the curves for eyeball volume, brain Volume, et(‘.,
show a rapid increase from 30 cm. oil.
 
The pars nervosa does not show the rapid increase u11til
about 35 cm. It approximates in the type of growth the enrves
for optic nerve Volume, eerebrum volume, and total body
weiglit. It resembles the type of growth of the optie—nerVe
volume in earlier fetal stages up to about 25 em.; from this
time on it follows more closely the growth curves of body
weigrllt and eerebrum volume.
 
 
 
A (-mnparismz of HM r«»lati‘z.'e rolmmns of the 101203 of Her:
Izumtm piwzafal 71.1/popl1;z/sis writ/1 /z‘nIumefrir* (lvfm'mimI.—
fir)-ns on human azlnlfs am] on animals
Rasmussen (’24) found the adult l1uma11 hypophysis to be
approximately 72 per cent pa.rs anterior, 18 per cent pars
nervosa, 2 per cent pars intermedia, a11d 8 per cent capsule.
These relative values when compared to t.l1ose for the hypophysis of the newborn are obviously in fair agfreemeiit. The
capsule of the hypophysis of the newborn a11d fetus is relatively much smaller in amount and more difficult to approximate than in the adult. For this reason its relative volume
was 11ot determined. For a eomparison of the relative values
of the lobes of the adult human gland with those of the newborn hypophysis it is necessary to express the former in
terms of the three lol)es only. The pars anterior of the adult
hypophysis comprises about 78 per cent of the gland volume,
the pars intermedia about 2 per eent, and the pars nervosa
about 20 per cent. The relative volumes of the lobes of the
hypophysis of the newborn have approximately the same
values. From this it is evident that the adult relationships
of the lobes of the gland are established at about the time of
birth or early in postnatal life.
 
Jackson (’17) found the hypophysis of the albino rat to be
quite variable as regards relative volumes of the lobes. A
comparison of the figures given by him shows that the relative
volumes of the epithelial and neural elements of the gland of
the adult rat and those of the human embryonic hypophysis
are similar. In the latter material the total epithelial portions are approximately 90 to 95 per cent of the gland volume,
while the relative volume of the posterior lobe is about 5 to 10
per cent. It is evident from the relative volumes of the ;,rland
lobes for the albino rat that the partes anterior and intermedia comprise about 92 or 93 per cent of the total gland
Weight and the posterior lobe approximately 7 or 8 per cent.
A comparison of the pars intermedia of the hypophysis of the rat with that of the human does not show such close
agreement.
 
 
Rasmussen (’21) analyzed the hypophysis of the woodchuck
with regards to the relative Volumes of each of the lobes. He
found the pars anterior to comprise about 46 per cent of the
entire organ (before and during hibernation), the pars intermedia about 2.46 per cent, and the remaining relative volume
to be pars nervosa. These proportions are, for the most part,
quite different from those found in the human hypophysis at
any stage in its development.
 
Bjorkman (’15) found the hypophysis of the rabbit to be
approximately 70 per cent pars anterior, 17 per cent pars
nervosa, and 13 per cent pars intermedia. The intermediate
lobe comprises considerable more of the gland than in any
of the other forms analyzed.
 
SUWMARY
 
The results of this study may be summarized as follows:
 
1. The growth in weight of the hypophysis during the embryonic and early fetal periods is Very rapid. It follows the
course of a shallow concave curve which rises rapidly in
specimens of 50 to 100 mm. (crown-rump).
 
2. The growth in weight of the hypophysis and its lobes during the fetal period resembles the general type of growth
characteristic of the body as a whole as Well as certain of
the organs. Total gland weight and weights of the partes
anterior and intermedia follow a curve of growth similar to
those for the volumes of the eyeball, midbrain, and spinal
cord. The fetal growth of the pars nervosa in weight resembles the curves for the optic nerve and cerebrum Volumes
and total body weight.
 
3. At birth the total weight of the hypophysis is about 107
mg. The calculated weights of the partes anterior, intermedia, and nervosa at this time are, respectively, 83.4 mg.,
2.05 mg., and 20.7 mg.
 
4. The diameters of the hypophysis increase slowly during
the fetal period. The anteroposterior and Vertical diameters
increase at approximately the same rate, the transverse diameter grows more slowly.
 
 
5. The calculated transverse diameter for the hypophysis of
a full-term fetus is 0.79 cm., the anteroposterior diameter is
0.57 cm., and the Vertical diameter is 0.49 cm.
 
6. The transverse diameter is the largest one of the hypophyseal fossa, and increases more in fetuses ranging from 20
to 55 cm. in total body length than do the anteroposterior and
vertical diameters.
 
7. The calculated transverse diameter of the hypophyseal
fossa at birth is 0.89 cm., the anteroposterior diameter is 0.54
cm., and the vertical diameter is 0.29 cm.
 
8. The relative volumes of the lobes of the hypophysis show
a gradual change during prenatal life. rfhe partes anterior
and intermedia comprise relatively more of the gland in embryonic and early fetal life than at birth. The pars nervosa
gradually increases in relative volume during prenatal life.
 
9. The hypophysis of the full—term fetus is roughly 78 per
cent pars anterior, 2 per cent pars intermedia, and 20 per cent
pars nervosa.
 
 
 
BIBLIOGRAPHY
 
BJGRKMAN, H. 1915-1916 Bidrag till hypofysens aldersanatomi hos kaninen.
Upsala Lakareforenings Forhandlingar, N. F., Bandet 21, pp. 49-108.
(Cited by Rasmussen, A. T., 1921.)
 
COMTE, L. 1898 Contribution a 1’étudc de l’hypophyse humaine et de ses relations avec le corps thyreoirle. Beitr. z. path. Anat. u. z. allg. Path.,
Bd. 23, s. 9o—i10.
 
CUTORE, G. 1910 Il corpo pineale di alcuni mammiferi. Arch. Ital. di Anat. e di
Embriol., vol. 9, pp. 402-464.
 
DUNN, H. L. 1921 The growth of the central nervous system in the human
fetus as expressed by graphic analysis and empirical formulae. Jour.
Comp. Ncur., vol. 33, pp. 405-491.
 
HAMMAR, J. A. 1914 Methode, die Monge dor Rinde und des Marks der Thymus, sowie die Anzahl und die Grosse der Hassallschen Kiirper zahlenmissig festzustellen. Zeitschrift f. angewandtc Anatomie u. Konstitutionslehre, Ed. 1, S. 311-396.
 
JACKSON, C. M. 1917 Effects of inanition and refeeding upon the growth and
structure of the hypophysis in the albino rat. Am. Jour. Anat., vol.
 
‘ 21, pp. 321-358.
 
LIPKA, J. 1918 Graphical and mechanical computation, pp. 122~127. New York.
 
LUCIEN, M. 1911 Les poids, les dimensions et la forme générale de l’hypophysc
hurnaine aux diiférents ages de la vie. Compt. Bend. (le l’Ass. (1. Anat.,
Treiz. Reun., T. 13, pp. 147-158.

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