spermatic plexuses, and from the sacral plexus. They have been made the
subject of special investigation by Dr. Robert Lee, who has successfully
repaired the omission made by Dr. William Hunter, in this part of the
anatomy of the organ. In his numerous dissections of the uterus, both in
the unimpregnated and gravid state, Dr. Lee has made the discovery of
several large nervous ganglia and plexuses. The principal of these,
situated on each side of the cervix uteri, immediately behind the
ureter, he terms the _hypogastric ganglion_; it receives the greater
number of the nerves of the hypogastric and sacral plexus, and
distributes branches to the uterus, vagina, bladder, and rectum. Of the
branches to the uterus, a large fasciculus proceeds upward by the side
of the organ, toward its angle, where they communicate with branches of
the spermatic plexus, and form another large ganglion, which he
designates the spermatic ganglion, and which supplies the fundus uteri.
Besides these, Dr. Lee describes _vesical_ and _vagina ganglia_, and
interior and posterior _subperitoneal ganglia_, and _plexuses_, which
communicate with the preceding, and constitute an extensive nervous rete
over the entire uterus. Dr. Lee concludes his observations by remarking:
“These dissections prove that the human uterus possesses a great system
of nerves, which enlarges the coats, blood-vessels, and absorbents
during pregnancy, which returns, after parturition, to its original
condition before conception takes place. It is chiefly by the influence
of these nerves that the uterus performs the varied functions of
menstruation, conception, and parturition, and it is solely by their
means that the whole fabric of the nervous system sympathizes with the
different morbid affections of the uterus. If these nerves of the uterus
could not be demonstrated, its physiology and pathology would be
completely inexplicable.”
APPENDAGES OF THE UTERUS.
The appendages of the uterus are inclosed by the lateral duplicatures of
peritoneum, called the broad ligaments. They are the Fallopian tubes and
ovaries.
[Illustration:
VISCERA OF THE FEMALE PELVIS.
1. The symphysis pubis; to the upper part of which the tendon of the
rectus muscle is attached. 2. The abdominal parietes. 3. The
collection of fat, forming the projection of the mons Veneris. 4.
The urinary bladder. 5. The entrance of the left ureter. 6. The
canal of the urethra, converted into a mere fissure by the
contraction of its walls. 7. The meatus urinarius. 8. The clitoris,
with its præputiam, divided through the middle. 9. The left nympha.
10. The left labium majus. 11. The meatus of the vagina, narrowed by
the contraction of its sphincter. 12. The canal of the vagina, upon
which the transverse rugæ are apparent. 13. The thick wall of
separation between the base of the bladder and the vagina. 14. The
wall of separation between the vagina and rectum. 15. The perineum.
16. The os uteri. 17. Its cervix. 18. The fundus uteri. The cavitas
uteri is seen along the center of the organ. 19. The rectum, showing
the disposition of its mucous membrane. 20. The anus. 21. The upper
part of the rectum, invested by the peritoneum. 22. The
recto-uterine fold of the peritoneum. 23. The utero-vesical fold.
24. The reflexion of the peritoneum, from the apex of the bladder
upon the urachus to the internal surface of the abdominal parietes.
25. The last lumbar vertebra. 26. The sacrum. 27. The coccyx.
]
The _Fallopian tubes_ or _oviducts_—the uterine trumpets of the French
writers—are situated in the upper border of the broad ligaments, and are
connected with the superior angles of the uterus. They are somewhat
trumpet-shaped, being much smaller at the uterine than at the free
extremity, and narrower in the middle than at either end. Each tube is
about four or five inches in length, and more or less flexuous in its
course. The canal of the Fallopian tube is exceedingly minute; its inner
extremity opens by means of the _ostium uterinum_ into the upper angle
of the cavity of the uterus, and the opposite end into the cavity of the
peritoneum. The free or expanded extremity of the Fallopian tube
presents a double, and sometimes a triple series of small processes or
fringes, which surround the margin of the trumpet or funnel-shaped
opening, the _ostium abdominale_. This fringe-like appendage to the end
of the tube has gained for it the appellation of the fimbriated
extremity; and the remarkable manner in which this circular fringe
applies itself to the surface of the ovary during sexual excitement, the
additional title of _morsus diaboli_. One of the processes, longer than
the rest, or, according to Cruveilhier, a distinct ligamentous cord, is
attached to the distal end of the ovary, and serves to guide the tube in
its seizure of that organ.
The Fallopian tube is composed of three tunices: an external and loose
investment derived from the peritoneum; a middle or muscular coat,
consisting of circular (internal) and longitudinal (external) fibers,
continuous with those of the uterus; and an external or lining mucous
membrane, which is continuous, on the one hand, with the mucous membrane
of the uterus, and at the opposite extremity with the peritoneum. In the
minute canal of the tube, the mucous membrane is thrown into
longitudinal folds or rugæ, which indicate the adaptation of the tube to
dilatation.
The _ovaries_ are two oblong, flattened, and oval bodies of a whitish
color, situated in the posterior layer of peritoneum of the broad
ligaments. They are connected to the upper angles of the uterus at each
side by means of a rounded cord, consisting chiefly of muscular fibers
derived from the uterus, the _ligament of the ovary_.
In _structure_, the ovary is composed of a cellulo-fibrous parenchyma or
stroma, traversed by blood-vessels, and inclosed in a capsule consisting
of three layers: a vascular layer, which is situated most internally,
and sends processes inward to the interior of the organ; a middle or
fibrous layer of considerable density; and an external investment of
peritoneum. In the cells of the stroma of the ovary, the small vesicles
or ovisacs of the future ova, the Graafian vesicles, as they have been
termed, are developed. There are usually about fifteen fully-formed
Graafian vesicles in each ovary; and Dr. Martin Barry has shown that
countless numbers of microscopic ovisacs exist in the parenchyma of the
organ, and that very few out of these are perfected so as to produce
ova.
After conception, a yellow spot, the corpus luteum, is found in one or
both ovaries. The _corpus luteum_ is a globular mass of yellow, spongy
tissue, traversed by white areolar bands, and containing in its center a
small cavity, more or less obliterated, which was originally occupied by
the ovum. The interior of the cavity is lined by a puckered membrane,
the remains of the ovisac. In recent corpora lutea, the opening by which
the ovum escaped from the ovisac through the capsule of the ovary, is
distinctly visible; when closed, a small cicatrix may be seen upon the
surface of the ovary in the situation of the opening. A similar
appearance to the preceding, but of smaller size, and without a central
cavity, is sometimes met with in the ovaries of the virgin; this is
_false corpus luteum_.
_Vessels and Nerves._—The arteries of the ovaries are the spermatic;
their _nerves_ are derived from the spermatic plexus.
The _round ligaments_ are two muscular and fibrous cords situated
between the layers of the broad ligaments, and extending from the upper
angles of the uterus, and along the spermatic canals to the labia
majora, in which they are lost. They are accompanied by a small artery,
by several filaments of the spermatic plexus of nerves, and by a plexus
of veins. The latter occasionally become varicose, and form a small
tumor at the external abdominal ring, which has been mistaken for
inguinal hernia. The round ligaments serve to retain the uterus in its
proper position in the pelvis, and during utero-gestation to draw the
anterior surface of the organ against the abdominal parietes.
LETTER XXIII.
ANATOMY OF THE FETUS.
Its Length and Weight—It Osseous, Muscular, and Vascular Systems—The
Fetal Circulation—Nervous System—Organs of Sense—Its Lungs, Heart, and
other Internal Organs.
As a matter of natural science, rather than one of real practical
utility, to you for whom I write these letters, I present you with a
description of some of the more important characteristics of the fetus.
In doing this I acknowledge myself indebted to Mr. Wilson, the
distinguished anatomist before referred to.
The medium weight of a child of the full period, at birth, is seven
pounds, and its length seventeen inches; the extremes of weight are four
pounds and three quarters, and ten pounds; and the extremes of
measurement fifteen and twenty inches. The head is of large size, and
lengthened from before backward; the face small. The upper extremities
are greatly developed, and the thorax expanded and full. The upper part
of the abdomen is large, from the great size of the liver; the lower
part is small and conical; and the lower extremities are very small in
proportion to the rest of the body. The external genital organs are very
large, and fully developed, and the attachment of the umbilicus is one
inch farther from the vertex of the head than from the soles of the
feet; and one inch farther from the ensiform cartilage than from the
symphysis pubis.
OSSEOUS SYSTEM.
The development of the osseous system is treated of in the various works
on anatomy. The ligamentous system presents no peculiarity deserving of
remark.
MUSCULAR SYSTEM.
The muscles of the fetus at birth are large and fully formed; they are
of a lighter color than those of the adult, and of softer texture. The
transverse striæ on the fibers of animal life are not distinguishable
until the sixth month of fetal life.
VASCULAR SYSTEM.
The circulating system presents several peculiarities: 1st. In the
heart; there is a communication between the two auricles by means of the
_foramen ovale_. 2d. In the arterial system; there is a communication
between the pulmonary artery and descending aorta, by means of a large
trunk, the _ductus arteriosus_. 3d. Also in the arterial system; the
internal iliac arteries, under the name of _hypogastric_ and
_umbilical_, are continued from the fetus to the placenta, to which they
return the blood which has circulated in the system of the fetus. 4th.
In the venous system; there is a communication between the umbilical
vein and the inferior vena cava, called the _ductus venosus_.
FETAL CIRCULATION.
The pure blood is brought from the placenta by the _umbilical vein_. The
umbilical vein passes through the umbilicus, and enters the liver, where
it divides into several branches, which may be arranged under three
heads: 1st. Two or three, which are distributed to the left lobe. 2d. A
single branch, which communicates with the portal vein in the transverse
fissure, and supplies the right lobe. 3d. A large branch, the _ductus
venosus_, which passes directly backward, and joins the inferior cava.
In the inferior cava the pure blood becomes mixed with that which is
returning from the lower extremities and abdominal viscera, and is
carried through the right auricle (guided by the Eustachian valve), and
through the _foramen ovale_, into the left auricle. From the left
auricle it passes into the left ventricle, and from the left ventricle
into the aorta, whence it is distributed, by means of the carotid and
subclavian arteries, principally to the head and upper extremities. From
the head and upper extremities, the impure blood is returned by the
superior vena cava to the right auricle; from the right auricle, it is
propelled into the right ventricle; and from the right ventricle into
the pulmonary artery. In the adult, the blood would now be circulated
through the lungs, and oxygenated; but in the fetus the lungs are solid,
and almost impervious. Only a small quantity of the blood passes
therefore into the lungs; the greater part rushes through the _ductus
arteriosus_, into the commencement of the descending aorta, where it
becomes mingled with that portion of the pure blood which is not sent
through the carotid and subclavian arteries.
Passing along the aorta, a small quantity of this mixed blood is
distributed by the external iliac arteries to the lower extremities; the
greater portion is conveyed by the internal iliac, hypogastric, and
umbilical arteries to the placenta; the hypogastric arteries proceeding
from the internal iliacs, and passing by the side of the fundus of the
bladder, and upward along the anterior wall of the abdomen to the
umbilicus, where they become the umbilical arteries.
[Illustration:
FETAL CIRCULATION.
1. The umbilical cord, consisting of the umbilical vein and two
umbilical arteries; proceeding from the placenta (2). 3. The
umbilical vein dividing into three branches; two (4, 4), to be
distributed to the liver; and one (5), the ductus venosus, which
enters the inferior vena cava (6). 7. The portal vein, returning the
blood from the intestines, and uniting with the right hepatic
branch. 8. The right auricle; the course of the blood is denoted by
the arrow, proceeding from 8 to 9, the left auricle. 10. The left
ventricle; the blood following the arrow to the arch of the aorta
(11), to be distributed through the branches given off by the arch
to the head and upper extremities. The arrows 12 and 13, represent
the return of the blood from the head and upper extremities through
the jugular and subclavian veins, to the superior vena cava (14), to
the right auricle (8), and in the course of the arrow through the
right ventricle (15), to the pulmonary artery (16). 17. The ductus
arteriosus, which appears to be a proper continuation of the
pulmonary artery, the offsets at each side are the right and left
pulmonary artery cut off; these are of extremely small size as
compared with the ductus arteriosus. The ductus arteriosus joins the
descending aorta (18, 18), which divides into the common iliacs, and
these into the internal iliacs, which become the hypogastric
arteries (19), and return the blood along the umbilical cord to the
placenta; while the other divisions, the external iliacs (20), are
continued into the lower extremities. The arrows at the terminations
of these vessels mark the return of the venous blood by the veins to
the inferior cava.
]
NERVOUS SYSTEM.
The brain is very soft, almost pulpy, and has a reddish tint throughout;
its weight at birth, relatively to the entire body, is as 1 to 6, and
the difference between the white and gray substance is not well marked.
The nerves are firm and well developed.
ORGANS OF SENSE.
_Eye._—The eyeballs are of large size, and well developed at birth. The
pupil is closed by a vascular membrane called the _membrana pupillaris_,
which disappears at about the seventh month. Sometimes it remains
permanently, and produces blindness. It consists of two thin membranous
layers, between which the ciliary arteries are prolonged from the edge
of the iris, and form arches and loops by returning to it again, without
anastomosing with those of the opposite side.
The removal of the membrane takes place by the contraction of these
arches and loops toward the edge of the pupil. The capsule of the lens
is extremely vascular.
_Ear._—The ear is remarkable for its early development; the labyrinth
and ossicula auditus are ossified at an early period, and the latter are
completely formed before birth. The only parts remaining incomplete are
the mastoid cells, and the meatus auditorius. The membrana tympani in
the fetal head is very oblique, occupying almost the basilar surface of
the skull; hence, probably, arises a deficient acuteness in the
perception of sound. It is also extremely vascular.
_Nose._—The sense of smell is imperfect in the infant, as may be
inferred from the small capacity of the nasal fossæ, and the
non-development of the ethmoid, sphenoid, frontal, and maxillary
sinuses.
FETAL LUNGS.
The _lungs_, previously to the act of inspiration, are dense and solid
in structure, and of a deep-red color. Their specific gravity is greater
than water, in which they sink to the bottom; whereas lung which has
respired will float upon that fluid. The specific gravity is, however,
no test of the real weight of the lung, the respired lung being actually
heavier than the fetal. Thus the weight of the fetal lung, at about the
middle period of uterine life, is to the weight of the body as 1 to 60.
But, after respiration, the relative weight of the lung to the entire
body is as 1 to 30.
FETAL HEART.
The _heart_ of the fetus is large in proportion to the size of the body;
it is also developed very early, representing at first a simple vessel,
and undergoing various degrees of complication until it arrives at the
compound character which it presents after birth. The two ventricles
form, at one period, a single cavity, which is afterward divided into
two by the septum ventriculorum. The two auricles communicate up to the
moment of birth, the septum being incomplete, and leaving a large
opening between them, the _foramen ovale_ (foramen of Botal).
The _ductus arteriosus_ is another peculiarity of the fetus connected
with the heart; it is a communication between the pulmonary artery and
the aorta. It degenerates into a fibrous cord after birth, from the
double cause of a diversion in the current of the blood toward the
lungs, and from the pressure of the left bronchus, caused by its
distention with air.
VISCERA OF THE ABDOMEN.
At an early period of uterine life, and sometimes at the period of
birth, as Dr. Wilson observed in the imperfectly-developed fetus, two
minute fibrous threads may be seen passing from the umbilicus to the
mesentery. These are the remains of the omphalo-mesenteric vessels.
The _omphalo-mesenteric_ are the first-developed vessels of the germ;
they ramify upon the vesicula umbilicalis, or yolk-bag, and supply the
newly-formed alimentary canal of the embryo. From them, as from a
center, the general circulating system is produced. After the
establishment of the placental circulation they cease to carry blood,
and dwindle to the size of mere threads, which may be easily
demonstrated in the early periods of uterine life; but are completely
removed, excepting under peculiar circumstances, at a later period.
The _stomach_ is of small size, and the great extremity but little
developed. It is also more vertical in direction the earlier it is
examined, a position that would seem due to the enormous magnitude of
the liver, and particularly of its left lobe.
The _appendix vermiformis cæci_ is long and of large size, and is
continued directly from the central part of the cul-de-sac of the cæcum,
of which it appears to be a constricted continuation. This is the
character of the appendix cæci in the higher quadrumana.
The large intestines are filled with a dark-green, viscous secretion,
called _meconium_, from its resemblance to the inspissated juice of the
poppy.
The _pancreas_ is comparatively larger in the fetus than in the adult.
The _spleen_ is comparatively smaller in the fetus than in the adult.
FETAL LIVER.
The _liver_ is the first-formed organ in the embryo. It is developed
from the alimentary canal, and at about the third week fills the whole
abdomen, and is one half the weight of the entire embryo. At the fourth
month the liver is of immense size in proportion to the bulk of the
fetus. At birth it is of very large size, and occupies the whole upper
part of the abdomen. The left lobe is as large as the right, and the
falciform ligament corresponds with the middle line of the body. The
liver diminishes rapidly after birth, probably from obliteration of the
umbilical vein.
KIDNEYS AND SUPRA-RENAL CAPSULES.
The _kidneys_ present a lobulated appearance in the fetus, which is
their permanent type among some animals, as the bear, the otter, and
cetacea.
The _supra-renal capsules_ are organs which appear, from their early and
considerable development, to belong especially to the economy of the
fetus. They are distinctly formed at the second month of embryonic life,
and are greater in size and weight than the kidneys. At the third or
fourth month, they are equaled in bulk by the kidneys; and at birth,
they are about one third less than those organs.
VISCERA OF THE PELVIS.
The _bladder_ in the fetus is long and conical, and is situated
altogether above the upper border of the ossa pubis, which are as yet
small and undeveloped. It is, indeed, an abdominal viscus, and is
connected superiorly with a fibrous cord, called the _urachus_, of which
it appears to be an expansion.
The _urachus_ is continued upward to the umbilicus, and becomes
connected with the umbilical cord. In animals it is a pervious duct, and
is continuous with one of the membranes of the embryo, the _allantois_.
It has been found pervious in the human fetus, and the urine has been
passed through the umbilicus. Calculous concretions have also been found
in its course.
The _uterus_, in the early periods of embryonic existence, appears
bifid, from the large size of the Fallopian tubes, and the small
development of the body of the organ. At the end of the fourth month,
the body assumes a larger bulk, and the bifid appearance is lost. The
cervix uteri in the fetus is larger than the body of the organ.
LETTER XXIV.
PHENOMENA OF LABOR.
Meaning of the Term—Its Divisions—Duration—Is Pain a Natural Condition
of Labor?—Ether and Chloroform.
Having, in the preceding letters, spoken of the various conditions of
pregnancy, I propose now making some remarks on the subject of labor.
I use the term _labor_ in the medical sense, which means the same thing
as _delivery_, or that process of nature by which the fetus, the
secundinus or membranes, and the placenta or after-birth, are brought
into the world.
In order to give you clearer ideas respecting labors, it is proper that
I should say something in regard to the different kinds that may occur.
On this subject authors have varied somewhat; some having divided labors
into few classes, while others have designated many. But first, a few
remarks on the _cause_ of labor.
I have remarked in another place, that among women the natural term of
utero-gestation is forty weeks, or nine calendar months. Occasionally,
it is true, the expulsory process commences within this period, or in
other cases extends beyond it; but on the whole, it happens so nearly at
this period, that we are compelled to conclude that it must be under the
influence of some particular agency, the nature of which we can in no
wise comprehend.
Some have maintained that it is the weight of the child, forcing it
downward at this precise period, which causes it to be expelled. Others
have supposed that the uterus contracts at the end of the forty weeks,
merely because it has no power of further expansion.
Others again have ascribed labor to the increasing activity of the child
and the uneasiness caused by its movements. But all of these hypotheses
are proved fallacious by the facts, that a large or small child is born
at the same period even with the same woman, and that a dead child,
unless the death took place at a very early part of the pregnancy, is
born in the same manner, and with the same punctuality as to period, as
a live one. “No fact,” says Dr. Denman, “is more incontestibly proved,
than that a dead child, even though it may have become putrid, is
commonly born after a labor as regular and natural in every part of the
process, as a living one.” We can, therefore, only state, that
parturition comes on at a stated period, in consequence of a law of
nature, or, in other words, as Avicenna remarks, “at the appointed time
labor comes on by the command of God.”
DIVISIONS OF LABOR.
Dr. Conquest has disposed of labors in the following manner: