conclusion that the rectal valve has a function. Its histologic
elements endow it with essentially passive and active properties. When
the muscular elements are relaxed and the gut is either greatly dilated
or else in a lesser measure distended, the valve is passively projected
across the channel to resist the hurried or uncontrolled descent of
the feces. The presence of the bands of fibrous tissue under the free
margin of the valve provides a guard or _control_ to receive and retain
the bolus, or, I may say, the valves receive a series of boluses, till
a sufficient pressure is made to stimulate the complex involuntary
mechanism of defecation to an expulsion of the feces or to a reversed
peristalsis. The presence of the feces or the involuntary movements
incident to their presence, signals the consciousness to cooperative
voluntary expulsory effort, or gives warning of the necessity of
voluntary resistance. In the event of the exercise of these forces in
the direction of resistance there seems to be some reason to believe
that an antiperistalsis returns the feces to the sigmoid flexure. The
same arrangement which sets in operation the involuntary factors of
defecation also provides for the minimum expenditure of energy on the
part of the voluntary forces for the reason that the gut’s contents are
collected on the surface of the unyielding sacrum and steadied there to
receive the pressure of the really expulsory voluntary effort. Such
an arrangement of the feces as is mentioned above further facilitates
defecation for the reason that the entire contents of the rectum are
not rushed upon the anus at once. The surgeon remembers that it is
usually impossible to reduce a hernia _en masse_.
The bundles of circular muscular fibers which constitute the muscular
element of the valve evidently belong to the same mechanism and have
the same function as those which form the ental sphincter. Their
usual state may be that of tonic contraction; they are relaxed by
inhibition; when the muscle is in a state of inaction the fibrous bands
are projected and support the valves across the channel of the rectum.
In health the valve is susceptible, under pressure, of a temporary
effacement.
If it be the function of the normal rectal valve to beneficently
retard the descent of the feces it is obviously true that it may be
the especial property of the valve, in certain other than normal
conditions, to maliciously obstruct the descent of the feces.
My experience convinces me that a perfect knowledge of the rectal
valve constitutes the key to an understanding of obstipation, rectal
stricture, and their sequels.
[Illustration: FIG. 31.--From a photograph of an anal end-view of a
cast-filled rectum; the average transverse diameter was 3½ inches (8.89
cm.), the vertical diameter was 3 inches (7.62 cm.).]
[Illustration: FIG. 32.--From a photograph of an external view of a
cast-filled rectum and its mesenteric attachment to the sacrum; taken
from an 18-months-old infant.]
OBSTIPATION IN INFANTS.
The infant strains at stool because of the imperfect development of the
anatomic features concerned in the mechanism of defecation. These are
as follows:
1. The infant’s lower gut is muscularly deficient.
2. Its great length and its mobility within the abdomen are obstructive
to defecation.
3. The rectal valves are obstructive.
4. The infant’s anus not being sufficiently expansible is also
obstructive to the descent of feces.
The specimens of infant rectums and sigmoids here pictured are all
fairly illustrative of the facts upon which the foregoing declarations
are based.
The dried specimens shown in the illustrations were prepared by
flushing the intestine and then fixing the subject in the genuacromial
posture; the anus was then fixed open and melted paraffin was injected
under about twelve ounces’ pressure. When the cast had hardened, that
portion of the gut which it occupied, was removed. Specimens shown in
Figs. 43 and 44 were prepared by placing the subject upon its back and
by opening the descending colon; the intestine below was then washed
out and the colon perforation fixed at the abdominal wound, which,
save for this point, was sewed up, the anus was tied up and as much
melted paraffin as would enter under two-pounds’ pressure was forced
into the gut; subsequently the sigmoid and rectum were removed as in
the other instances. After immersion in alcohol the specimens were
varnished.
[Illustration: FIG. 33.--A semilunar valve drawn as seen under a glass
magnifying five diameters. _A_, mucous membrane; _B_, fibrous tissue;
_C_, bundles of circular muscular fibres; _D_, vein; _E_, artery; _F_,
vein; _G_, artery; _H_, areolar and adipose tissue.]
[Illustration: FIG. 34.--The instrument case; the drawers opening on
three sides afford access to any drawer without disturbing the position
of the others.]
Following are the memoranda of a few of the autopsies made in this
study:
CASE 1.--Female, stillborn, height 16 inches (40.64 cm.);
circumference at anterior superior spinous process 7½ inches
(19.05 cm.); anterior superior spinous process diameter 3
inches (7.62 cm.); ensiform to pubes 4 inches (10.16 cm.);
transverse diameter pelvic outlet ¾ inch (1.90 cm.);
peritoneum at last vertebra of coccyx. (Fig. 35).
[Illustration: FIG. 35.--The rectum of an infant, stillborn; muscular
coat undeveloped. Filled from below.]
[Illustration: FIG. 36.--Side view of the specimen shown in Fig. 35.
Antero-posterior angulation at third sacral vertebra.]
CASE 2.--Female, aged 1 hour, height 17 inches (43.18 cm.);
circumference at anterior superior spinous process 7½ inches
(19.05 cm.); anterior superior spinous process diameter 2½
inches (6.35 cm.); ensiform to pubes 4 inches (10.16 cm.);
transverse diameter pelvic outlet ½ inch (1.27 cm.); peritoneum
at last vertebra of coccyx. (Fig. 37).
[Illustration: FIG. 37.--Front view of the rectum of an infant aged one
hour; autopsy while in a state of rigor mortis. The rectum being nearly
perpendicular and the sigmoid almost tied in a knot. Filled from below.]
[Illustration: FIG. 38.--Side view of the specimen shown in Fig. 37.]
CASE 3.--Male, aged 1 month, height 23 inches (58.42 cm.);
circumference at anterior superior spinous process 9 inches
(22.86 cm.); anterior superior spinous process diameter 3½
inches (8.89 cm.); ensiform to pubes 4 inches (10.16 cm.);
transverse diameter pelvic outlet ⅝ inch (1.59 cm.); peritoneum
at last vertebra of coccyx.
[Illustration: FIG. 39.--Front view of the rectum of an infant aged one
month; autopsy while in the state of rigor mortis. Filled from below.
Two-third life-size.]
[Illustration: FIG. 40.--Side view of the specimen shown in Fig. 39.]
CASE 4.--Female, aged 6 weeks, height 24 inches (60.96 cm.);
circumference at anterior superior spinous process 10½ inches
(26.67 cm.); anterior superior spinous process diameter 3
inches (7.62 cm.); ensiform to pubes 5½ inches (13.97 cm.);
transverse diameter pelvic outlet ⅝ inch (1.59 cm.); peritoneum
at last vertebra of coccyx. (Fig. 41).
[Illustration: FIG. 41.--Front view of the rectum of an infant aged six
weeks. Filled from below.]
[Illustration: FIG. 42.--Side view of the specimen shown in Fig. 41.]
CASE 5.--Female, aged 2 months, height 20 inches (50.80 cm.);
circumference at anterior superior spinous process 8 inches
(20.32 cm.); anterior superior spinous process diameter 3
inches (7.62 cm.); ensiform to pubes 3½ inches (8.89 cm.);
transverse diameter pelvic outlet ¾ inch (1.90 cm.); peritoneum
at last vertebra of coccyx. (Fig. 49).
CASE 6.--Male, aged 6 months, height 24 inches (60.96 cm.);
circumference at anterior superior spinous process 10 inches
(25.40 cm.); anterior superior spinous process diameter 4
inches (10.16 cm.); ensiform to pubes 5 inches (12.70 cm.);
transverse diameter pelvic outlet ¾ inch (1.90 cm.); peritoneum
at last sacral vertebra. (Fig. 43).
[Illustration: FIG. 43.--Front view of the rectum of an infant aged
six months. Filled from below after disappearance of rigor mortis.
Two-thirds life-size.]
CASE 7.--Male, aged 6 months, height 24 inches (60.96 cm.);
circumference at anterior superior spinous process 12 inches
(30.48 cm.); anterior superior spinous process diameter 4
inches (10.16 cm.); ensiform to pubes 5 inches (12.70 cm.);
transverse diameter pelvic outlet ¾ inch (1.90 cm); peritoneum
at first bone of coccyx. (Fig. 44).
[Illustration: FIG. 44.--Front view of the rectum of an infant aged six
months. Filled from above after disappearance of rigor mortis.]
[Illustration: FIG. 45.--Side view of the specimen shown in Fig. 44.
The mesentery from sacrum and coccyx to the rectum is fairly well
shown, but is shown shorter than in the fresh state, alcohol immersion,
varnishing and drying having shrunken it. Observe also how nearly the
peritoneum approaches to the anus.]
CASE 8.--Male, aged 17 months, height 25 inches (63.50 cm.);
circumference at anterior superior spinous process 12 inches
(30.48 cm.); anterior superior spinous process diameter 4
inches (10.16 cm.); ensiform to pubes 6 inches (15.24 cm.);
transverse diameter pelvic outlet 1 inch (2.54 cm.); peritoneum
at last sacral vertebra.
Examination of the pictures of _the dried specimens reveals that the
wall of the infant rectum and sigmoid flexure is thin_ compared to that
of the adult.
It is impossible to distinguish the longitudinal muscular bands which
are so apparent in the gut of the adult. The infant gut being very
deficient in muscular elements, therefore the intrinsic power of
peristalsis cannot be present in that degree necessary to it as a
component factor of defecation.
_The relations of the peritoneum to the rectum_ of the infant also
contribute to the difficulties of defecation, as also does the
relatively _great length of the descending colon and sigmoid flexure_.
In young children the length of sigmoidal mesentery from its attachment
to the parietes to its invagination of the lower loop of the sigmoid
is often greater than the distance from the promontory of the sacrum
to the distal bone of the coccyx. (See Figs. 44 and 45.) From the
sigmoidorectal juncture to the beginning of the middle third of the
rectum the mesentery rapidly shortens but apparently completely invests
the upper third of the rectum. The middle and lower thirds are not so
completely invested, and present upon their posterior parts a vertical
lane bare of peritoneum, from the borders of which the peritoneum
is reflected in lateral directions. This uncovered part of the gut
is not applied directly to the sacrum and coccyx. There is a space
between which is occupied by loose connective tissue. The distance from
the dorsal parietes to the gut is variable here, being from one-half
to one-fourth of an inch (1.27 to .63 cm.). At the beginning of the
middle third there is usually a gradual decrease in the length of the
peritoneal band as it descends, till it is one-eighth or possibly but
one-sixteenth of an inch (.32 or .16 cm.) in length at the last bone of
the coccyx; it rapidly shortens from this point to its termination.
The parietal peritoneum descends over the ischial tuberosities and
approaches nearly to the ental sphincter muscle. In the newly-born the
peritoneum is situated within one-fourth inch (.63 cm.) of the anal
skin.
The disproportionately great length of the descending colon and
mesentery of the infant obviously contributes to the possibility of
angulation of the gut.
We may see in the presence in the child of lax and long, or relatively
long, peritoneal ligaments, and in the great length of the descending
colon and the consequent probability of numerous acute angulations
in the infant sigmoid and rectum, and in the mobility of these parts
within the abdomen, the possibility of development of a perfect adult
mechanism for defecation. The essential features of this development
are two: (1) the growth of prostate or uterus and their supports which
relatively fix the lower rectum; and (2) the downgrowth and outgrowth
of the pelvic bones and the consequent conversion of mesenteric
peritoneum to parietal peritoneum, which shortens the adult mesentery
and in some measure fixes the upper rectum; thus the entire rectum is
steadied to facilitate discharge when the mechanism of defecation is
set in operation.
[Illustration: FIG. 46.--Diagrammatic of this gut in the empty
state, therefore its flexions are not the same as those shown in the
photographs. In the partly filled state, which is the condition about
the time of defecation, the flexions and positions of these parts would
be intermediate to those of the filled and empty conditions. (The
dotted lines indicate positions of valves.)]
The diagrammatic figures do not exaggerate these obstructive elements.
The collateral muscles which assist in the performance of the act of
defecation force the feces in the direction of the lower angle in each
flexion, and in that flexion whose onward, or, to be paradoxic, whose
downward direction for the time points upward (Fig. 46), the auxiliary
pressure is in the direction opposite to that of peristalsis.
[Illustration: FIG. 47.--Diagrammatic, showing direction of forces and
resistance in infant, in defecation.]
[Illustration: FIG. 48.--Diagrammatic, showing direction of forces and
resistance in adult, in defecation.]
Inspection of the pictures of the dried specimens reveals the
angulations referred to, which may be expected to be more numerous the
more segmentary the gut’s contents.
_The third feature obstructive to defecation in infants is the rectal
valve._ It is a feature and factor which not only is not recognized,
but is one whose very anatomic existence has been persistently disputed
by Matthews, Kelsey, and others. It was imperfectly described as an
anatomic feature of the rectum by Mr. Houston in the Dublin Hospital
Reports in 1830, and in 1887 Dr. Walter A. Otis more practically
demonstrated its presence; neither of these gentlemen, however,
attributed to it the characteristic element of an anatomic valve,
although happily and by chance bestowing upon it its proper name. A
number of investigators have discovered this organ and have miscalled
it by various names and given it widely varying descriptions; but a
greater number still deny its existence and critically strive to
dissolve away the imperfect evidence recorded in medical literature.[17]
The pictures here shown of the dried specimens prove that in the infant
the valve is such a matter of fact that its existence is no longer a
question for debate.
[Illustration: FIG. 49.--The rectum and sigmoid of an infant aged
two months. The photograph shows the interior of the anterior half.
Portions of two valves are noticed at the middle part.]
[Illustration: FIG. 50.--The interior view of the opposite posterior
half of the rectum shown in Fig. 49, the two valves shown in Fig. 49
being continued toward each extremity of the ampulla. The sigmoid is
out of focus.]
[Illustration: FIG. 51.--The paraffin cast removed from the gut shown
in Figs. 49 and 50.]
The fetal specimens pictured indicate that the valves are particularly
well developed early in embryonic life. The infant specimen shown in
Fig. 49 is marked by two valves, situated so close together that the
middle portion of the rectum presents its longest diameter at right
angles to the main direction of the gut. Another valve may be seen at
the juncture of the upper portion and the sigmoid flexure.
It must be readily seen that the presence in the rectum of such a
structure as an anatomic valve would be essentially obstructive to the
passage of feces.
In studying the physics of the rectum it is important that we recognize
that the posterior wall from which the mesentery is reflected is
less movable than other parts in the circumference, hence distention
of the rectum not only tends to carry a given point of its wall away
from the point opposite to it, but also carries it away from a given
point cephalad or caudad. So it may be assumed that if the two valves
situated at the middle of the cast-distended dried specimen (Fig. 49)
are three-eighths of an inch (.95 cm.) separated, and that the two
opposite walls of the rectum in the portion bounded by these valves are
one inch (2.54 cm.) apart, that in a state of the gut’s collapse or
systole the valves would be in contact, and thus afford a very definite
obstruction to the descent of semisolid feces.
The _bony pelvic outlet_ in the infant is so contracted that the limits
of anal expansion are such as to almost defeat the passage through it
of other than fluid feces. It should be remembered that the normal
average measurement from ischial tuberosity to ischial tuberosity
in the adult is about four inches (10.16 cm.), and it is a fact
proven by our observation that the average transverse diameter of the
newly-born infant’s pelvic outlet is but a little more than one-half
inch (1.27 cm.), the pubococcygeal measurement is even less. Those
who are familiar with instrumental divulsion of the adult anus may
have observed that two and a quarter inches (5.71 cm.) is the average
limit of lateral separation of the anus, the remaining portion of the
pelvic outlet being filled with the compressed soft tissues of the
ischiorectal space. Therefore it may be estimated that nine-sixteenths
at most, of the diameter of the pelvic outlet is the reasonable limit
of expansibility of the anus for the passage of feces. Applying this
calculation to the infant we find that if the ischial tuberosities are
one-half inch (1.27 cm.) separated, that the anal expansibility is but
five-sixteenth of an inch (.79 cm.), which is, as we know, the diameter
of a No. 22 sound (French scale). Reference to the paraffin cast of
the infant gut (Fig. 51) indicates that the average distensibility of
the sigmoid flexure and rectal chambers, in which the feces when firm
are formed, is four or five times that of the anal expansibility; thus
it is readily perceived that compared to the adult the juxtaposition
of the ischial tuberosities in the infant supplies a most obstinate
obstructive factor in defecation.
To collate in brief:
1. The muscular development of the adult rectum and lower sigmoid is
plainly apparent in the plates here exhibited of the fresh specimens. A
deficient muscularity is observed in the infant specimens.
2. The peritoneal band of these parts in the adult is observed to be,
relatively, very considerably shorter than that in the infant, and the
sigmoid flexure is relatively shorter.
3. The rectal valves appear to bear the same proportion to the gut in
both adult and infant, but when we remember the difference in muscular
development in the two the disproportionately greater resistance of the
valve in the infant rectum is obvious.
4. The anal expansibility is remembered as adequate in the adult, and
is seen to be deficient in the infant.
Correlative to the facts just stated we must recognize that the adult
rectum has resident within its own wall a powerful expulsive muscular
mechanism; that the shortening of the mesentery holds the upper rectum
steady under the applied auxiliary forces; that the angulations of the
normal sigmoid are not necessarily obstructive, though in a desirable
measure retardative; that the forward incline of the lower sacrum and
coccyx behind, and the development of the uterus and prostate and
their inherent supports in front, provide the lower adult rectum with
a firm funnel-like arrangement which guides the feces directly upon
the os internum of the anus; that the valves divide the feces into
portions to facilitate their separate successive discharge, and finally
in sequence, that the physiologic descent of the structures of the
ischiorectal space reduces this last resistance to the minimum in adult
defecation.
Straining, the ruptures and prolapses, obstipation, retention of feces,
and the multitudinous consequent ills demand our consideration, though
this study forces the conclusion, I believe, that the individual’s
escape is ultimately assured by process of development, and that for
the normally formed infant, the physician will find the solution of the
problem of difficult defecation in the solution of the stool.
TREATMENT.
Diet, hygroscopic suppositories, and fluid injections which may render
more fluid the intestinal contents will favor their descent through the
convoluted gut, the valvulated rectum, and the contracted anus.
Massage of the abdomen over the region of the colon aids in (1) the
development of the auxiliary abdominal muscles of defecation and of
the intrinsic expulsory muscles in the intestinal wall; and further,
such manipulations (2) directly propel the gut’s contents along the
tortuous course of the bowel and hence (3) reduce, inasmuch as they
may overcome the obstructive features of the valve.
If there be an overgrowth of the rectal valve and if it form an almost
impassable barrier to the descent of the feces it may be in some
measure overcome in infants by the dilatation which may be effected
through the means of the gently introduced trained finger. In case the
defective valves are present in the form of diaphragmatic strictures or
membranous septa with circular aperture, the valve may be safely cut by
a method described in another place.
As at birth the pelvic bones are not yet united and as the rami of
the ischium and pubes are still quite cartilaginous it is obviously
possible that a little energy intelligently directed upon the anus
from without will spread the pelvic outlet, whereas the infant labors
ineffectually with his own forces applied as they are from within. The
nurse, therefore, may be directed to pare away her nail-ends, lubricate
her fingers and gently introduce the smallest finger through the anus.
Daily gradual dilatation of the infant’s pelvic outlet should be
practised, graduating from finger to finger until the required degree
of dilatation be reached. The introduction of the finger independent of
its dilating uses incites the mechanism of defecation to action.
Rachitic subjects with abnormal contraction of the pelvic outlet demand
forcible divulsion of the ischial tuberosities.
[Illustration: FIG. 52.--A three-and-a-half-months fetus. A photograph
showing the posterior half of the rectum prepared by the paraffin-cast
process. The rectal valves are noticeably prominent at this stage of
fetal development.]
[Illustration: FIG. 53.--A five-months fetus. A photograph showing
a paraffin cast-filled rectum in situ; the other organs having been
dissected away.]
OBSTIPATION IN THE ADULT.
If it be the function of the normal rectal valve to beneficently retard
the descent of the feces it is obviously true that it may be the
especial property of the valve in certain other than normal conditions
to maliciously obstruct the descent of the feces.
There are three forms of valvular obstruction:
1. _Anatomic coarctation of the valves_ may afford an exaggerated
physiologic resistance to the descent of the feces (Fig. 54).
2. _Congenital hyperplasia of the rectal valve_ is a condition
classically described as diaphragmatic stricture or membranous septum
in the abdominal rectum.
3. _Hypertrophy of the rectal valve_ constitutes the classic annular
stricture of the abdominal rectum.
[Illustration: FIG. 54.--Anatomic coarctation of valves.]
THE SYMPTOMS.