may be divided into primary and secondary--the former when the morbid
cause is local and independent of disease elsewhere, the latter when it
is consequent upon or incident to some other bodily affection. Among
the primary lesions may be classed congenital malformations, prolapse
of the rectum, hemorrhoids, and some varieties of new growths; also
diseases caused by local irritations, infection, or traumatism, such as
proctitis, ulceration, fissure, non-malignant stricture, chancroidal
invasion and primary syphilis, including obstruction of the bowel by
impacted feces and foreign bodies. Thread-worms and various cutaneous
eruptions about the anus may also be included among the causes of the
primary diseases of this portion of the alimentary canal.
The secondary affections are quite numerous, and may be caused by
direct extension of disease from the colon, as in the dysentery
following typhoid fever, and follicular enteritis, or entero-colitis of
children; by contiguity, from diseases in neighboring organs--_e.g._
ischio-rectal abscess causing fistula--or by changes in the nervous or
vascular supply, such as is seen in spasmodic contraction, paralysis,
epidemic dysentery, cholera, and the action of certain remedies.
The rectum, the third or terminal portion of the large intestine, has
no sharply-defined upper limits: it is usually understood to begin at
the sigmoid flexure, opposite the left sacro-iliac symphysis; it is
from six to eight inches in length and terminates in the anus. As the
sigmoid flexure is the narrowest portion of the colon, so the calibre
of the first part of the rectum is narrower than the portion below,
where it gradually becomes more commodious, and near the anus presents
a peculiar condition of the walls which gives it a capacity for
remarkable distension. The rectum, which is somewhat cone-shaped, in
its anatomical and pathological characters retains those of the large
intestine with slight variation. Upon the upper or first part of the
rectum the duplicature of the peritoneum is continued, forming the
meso-rectum, which invests the bowel, attaching it to the sacrum. Below
this the middle portion of the rectum (extending to the tip of the
coccyx) is attached to the sacrum by connective tissue only, but also
has a peritoneal investment on the upper portion of its anterior
surface.
{878} The third or terminal part of the rectum, which is only an inch
and a half in length, and is entirely without peritoneal covering,
terminates at the anus. The circular and transverse muscular fibres,
mucous crypts, and appendages throughout the rectum are identical with
those above, except that the general muscular tunic is thicker; but the
longitudinal fibres are less distinctly aggregated into bands than in
the colon, being disposed in a more uniform manner, except that, like
the circular fibres, they are especially aggregated between the
sacculi. The fact that the meso-rectum limits the mobility of the upper
and more narrow part of the rectum has led some to locate a third
sphincter at this point, but the existence of such an organ has not
been generally admitted. Van Buren characterizes it as an organ which
"anatomy and physiology had been equally unsuccessful in assigning
either certainty of location or certainty of function."[1]
[Footnote 1: Kelsey, _Diseases of the Rectum and Anus_, New York, 1882,
p. 20.]
The anus guards the outlet of the bowel by its double sphincter muscle,
which under normal circumstances affords voluntary control, within
certain limits, over defecation. The well-known peculiarity of the
vascular supply, a sort of erectile tissue being formed by the inferior
hemorrhoidal plexus and the passage of some of the efferent veins
through the sphincter muscle, by which they are subjected to pressure,
is very favorable to the development of certain forms of disease which
will be considered among the local disorders. As embryology has thrown
considerable light upon the pathology of morbid growths by
demonstrating relationships that were previously unsuspected, so a
consideration of the development of the lower portion of the intestinal
canal may lead to a better understanding of some of its diseases,
especially those which are symptomatic or secondary. In early foetal
life the third division of the primitive intestine, the pelvic portion,
terminates in a cloaca in common with the urachus; subsequently, about
the eighth week, a partition (the perineum) is formed which divides the
cavity into two portions, the uro-genital sinus and the anal cavity. In
the mean time, at an early period a depression occurs on the cutaneous
surface at the site of the anus, which deepens progressively until it
encounters the primitive intestine, with which it unites at the end of
the fourth week, and the continuity of the tube becomes established. It
therefore is seen that the rectum in its upper and middle portions is
derived from the internal and middle layers of the blastodermic
membrane, while its lower third, with the anus, like the buccal cavity,
is formed by the external and middle layers.
In its diseases, then, the greater part of the rectum would seem to
naturally participate in those of the large intestine, to which it
structurally belongs, while its inferior portion and the anus would
partake more in the disorders of the general cutaneous system. This
peculiarity of development also explains the difference noticed in the
vascular supply. The rectal veins are usually divided, like the rectal
arteries, into three sets--superior, middle, and inferior. They are
arranged so as to form two distinct venous systems, the rectal
returning its blood through the inferior mesenteric veins into the
portal system, the anal terminating in the internal iliac. The first
system is made up of the superior hemorrhoidal, the second of the
remaining veins.
The superior hemorrhoidal forms a venous plexus which surrounds the
{879} internal sphincter muscle; the inferior hemorrhoidal vein also
forms a plexus, but it is subcutaneous and principally below the
inferior border of the external sphincter.
There are, however, a number of communicating branches passing along
the walls of the rectum from one plexus to the other. The internal
hemorrhoidal veins also communicate freely with the branches of the
internal iliac around the trigone of the urinary bladder by means of
small vessels, which pass through the prostate gland and seminal
vesicles. By this method of anastomosis some relief is afforded when
there is an obstruction in the portal circulation, which is such a
common cause of turgescence of these veins, often resulting in
permanent dilatation or hemorrhoids.
At the lower part, or at the junction of the middle and lower third of
the rectum, the internal circular fibres of the muscular coat of the
intestine become quite numerous, forming what is called the internal
sphincter muscle; it is nearly an inch in breadth, and completely
surrounds the lowest part of the rectum. It is about an inch above the
margin of the anus; its muscular fibres are of the involuntary or
unstriped variety; in function it assists the external sphincter in
closing the anus and preventing the involuntary escape of the contents
of the bowel.
The external sphincter lies directly under the skin and upon the
internal sphincter and the levator ani muscle; its fibres encircle the
anus: arising from the coccyx, they are inserted into the tendinous
centre of the perineum, joining the transversus perinæi, the levator
ani, and accelerator urinæ muscles. The sphincter ani is constantly in
a state of tonic contraction, but the force of its contraction may be
voluntarily increased. In the skin and superficial fascia are found
minute branches of the pudic and small sciatic nerves; in the
ischio-rectal space the internal pudic nerve; crossing about the centre
are the inferior hemorrhoidal nerves, which are distributed to the anus
and the lower portion of the rectum; the perineal nerve is especially
distributed to the anterior part of the anus.
Thus it is seen that the rectum and anus have vascular and nervous
supplies of considerable diversity and importance.
Congenital Malformations.
The simplest form of congenital malformation in this region consists in
an anus of insufficient size for the natural demands of the system, but
in no other manner abnormal. The most frequent variety of imperforate
anus is where complete occlusion is effected by the common integument
or by two cutaneo-mucous flaps, which owing to defective development
remain united without forming a raphé or perceptible line of union. The
rectum is not involved, and when the child strains the contained
meconium causes bulging of the part, which disappears under slight
pressure, but reappears when again free. In other cases the occluding
tissue is very firm, dense, with a disposition to pucker or form rugæ.
The sphincter muscle is rarely perfect, and though an artificial anus
may be made, years may elapse before the child can control the
evacuation. In conjunction with an imperforate anus the colon may
terminate in a cul-de-sac, or it may communicate with the urethra, the
bladder, or the vagina.
{880} An imperforate rectum has been known to discharge at the
umbilicus, upon the face, under the scapula, upon the penis or the
anterior part of the scrotum. Sometimes, though very rarely, a common
cloaca has been found, as in fowls, common to the rectum and to the
genito-urinary organs; and still more rarely the rectum has opened in
abnormal sites upon the perineum and upon the buttocks.
The anus may be entirely absent. The rectum may be entirely absent or
it may be incomplete, terminating at various distances from the anus.
These malformations of the bowel may be associated with a perfect anus,
or with any of its imperforate forms, or with a fecal fistula. In
occlusion of the rectum the offending structure is in some cases a
hymen-like fold of mucous membrane, which, during straining, can be
recognized by the finger as a fluctuating protrusion; while in others
it consists of a mass of dense fibrous tissue which extends upward from
an inch to an inch and a half: in the former there is always found a
normal anus; in the latter there is either no trace of anus or one in a
more or less rudimentary state. In those cases where the rectum is
entirely absent the intestine terminates either in a cul-de-sac or a
fecal fistula; very rarely the rectum is replaced by a
fibro-ligamentous cord or band which springs from the colon, and,
descending toward the bladder, blends with the connective tissue of the
part. In the latter the pelvis is always in an imperfect state of
development, being much contracted in its lower diameters, and the anus
is absent; and Rokitansky and Curling lay stress upon the
non-development of the pelvis as a diagnostic guide in determining the
absence of the rectum. The passage of a sound into the bladder or
vagina is a procedure of some diagnostic value, as if its point
impinges directly against the sacrum it may be presumed that no rectum
exists. If the malformation is of such a character that the fecal
matter can find no exit, a train of symptoms ensues analogous to those
seen in the adult affected with intestinal obstruction: the infant
cries and is constantly restless, refuses food, vomits, the abdomen
distends, and death speedily ensues. A remarkable exception to this
rule was the case mentioned by Bodenhamer of a child with absence of
the rectum who was not operated on until three months after birth, and
who was apparently in perfect health. At the operation the intestine
was found three inches from the surface, and the child made a good
recovery.
Although the statistics of this class of malformations are somewhat
contradictory and confusing, it is safe to state that more male than
female children are so afflicted.
The prognosis in the large majority of these cases is grave, for unless
the operator can see or feel the fluctuating protrusion, or can
recognize it after a very slight exploratory incision, he is working
totally in the dark and in close proximity to the peritoneum.
Hemorrhage, peritonitis, pelvic cellulitis, and septicæmia diminish the
chances for recovery. Indeed, the majority of these cases are scarcely
amenable to surgical treatment.
{881} PRIMARY DISEASES OF THE RECTUM AND ANUS.
Prolapse and Procidentia of Rectum and Anus.
These conditions obtain most frequently at the two extremes of life,
infancy and senility, but have a very different causation in each.
Prolapse of the bowel may be partial or complete--partial when a
portion of the mucous membrane is extruded, and complete when the
entire rectum appears outside the anal orifice. A predisposing cause in
infants is found in the mobility of the bowel--in the fact that it and
the sacrum are much less curved than in the adult, and the abdominal
viscera are more voluminous: this, associated with the undeveloped
state of the muscular system, causes the weight and strain to act
directly and forcibly upon the sphincters, and the extrusion takes
place. It is often excited by allowing children to sit for a length of
time upon the chamber-vessel. It is frequently caused among children by
the presence of vesical calculi, by Oxyuris vermicularis, diarrhoea,
constipation, dysentery, polypi, and by the long-continued acts of
coughing and crying.
In adults and the aged it may be caused by loss of tone of the anus and
rectum in chronic diarrhoea and dysentery, or from the energetic action
of drastic cathartics, by urinary calculi, the long-continued use of
enemata, chronic cough, diarrhoea alternating with constipation,
stricture of the urethra, prostatic hypertrophy, tenesmus due to the
presence of polypi, and by the pressure of a pelvic tumor. It may
accompany procidentia uteri and hemorrhoids. An incomplete, reducible
prolapse consists of two or more overlapping plications of
normal-looking mucous membrane, sensitive but painless. In these cases
there is provoked a hyperplasia of much-elongated connective tissue in
the submucous space which undergoes serous infiltration and causes an
oedematous condition of the part. In a complete prolapse the entire
rectum--all of its component layers--is protruded through the anus. In
a recent case the folds of the gut are well marked, but in one where
the bowel has remained in this abnormal condition for some time the
submucous tissue becomes charged with inflammatory deposit which
effaces the plications and causes the bowel to become pale, hard, dry,
and tough; and finally pigmentation occurs and the part assumes
somewhat the character of true skin. These vary greatly in size, from
the slightest protrusion of mucous membrane to a tumor the size of a
melon. Usually they are reduced with ease, but their reappearance is
occasioned by the slightest tenesmus.
In old age the soft parts of the floor of the pelvis and the anal
sphincters lose to a great extent their tone and contractile vigor, and
the rectum, also participating in this change, is often unable to
withstand the increased thrust of the diaphragm and the compression of
the abdominal muscles during defecation; which act frequently demands
more exertion on account of a tendency to constipation in advanced
life.
In these long-standing cases of senile procidentia it is a matter of
experience, verified by post-mortem dissection, that the fibres of the
sphincters and of the levatores ani muscles are flattened, pale, and
stretched beyond the possibility of contraction, while the entire
perineum is in a state of atrophy.
{882} Polypi of the Rectum.
There are two varieties of these--the gelatinoid or soft, and the
fibroid or firm. The latter is of rare, the former of common,
occurrence, especially in children under the age of twelve years. The
fibroid polypus is only found in adults, and is composed of dense
connective-tissue elements and blood-vessels. The gelatinoid or soft
polypi are also partly composed of connective tissue and vessels, but
much finer than in the other: they contain hypertrophied follicles and
are covered with spherical epithelium. They resemble nasal polypi, but
are more dense. These growths are not malignant in character, but are
very troublesome, as they are almost always pedunculated, the stem
being from half an inch to four inches in length, which admits of the
descent of the tumor within the grasp of the sphincters during
defecation, and frequently admits of its escape from the anus. Their
presence is not free from danger, as they are very vascular, bleed
readily, and are sometimes detached by the breaking of the pedicle
during defecation. They frequently bleed spontaneously. The presence of
these abnormal growths teases the rectum and brings on tenesmus and
frequent desire to go to stool; the feces are flattened, and with them
escapes a quantity of glairy red mucus which has been compared to thin
currant-jelly. When caught in the grasp of the sphincters they often
bleed profusely, and especially is this the case with children so
affected. The presence of these bodies is accompanied with a sense of
weight and uneasiness in the bowel. They may be single or multiple;
they may be round, reniform, oval, fusiform, or irregular; they may be
smooth or villous. In size they vary from that of a marble or cherry to
that of a small hen's egg, and they are usually found about three
inches above the anus, but they vary in position from a point just
within the sphincter to one six inches up the rectum. Their presence is
usually diagnosticated without difficulty, or, if any is experienced, a
digital exploration will reveal them. A child with functional
disturbances of the bowels accompanied with frequent hemorrhages should
be examined for polypus. One of these growths sometimes unpleasantly
complicates a case of hemorrhoids.
A rectal polypus is an adenoma, consisting of dilated glands of
Lieberkühn imbedded in connective tissue, also containing nerves and
blood-vessels, and is covered with the epithelium of the bowel.
Hemorrhoids, or Piles.
These are usually fibrous when situated below, or vascular when
situated above, the sphincter ani muscle. They are conveniently known
as external and internal piles, but in some instances it is impossible
to say whether these tumors are external or internal. In either variety
they are due to an abnormal state of the blood-vessels, and especially
of the plexus of superior, middle, and inferior hemorrhoidal veins
disposed around the lower extremity of the rectum immediately above the
internal sphincter muscle. The inferior mesenteric and internal iliac
veins receive a large portion of the blood from this plexus, so that a
very free intercommunication exists, around the lower portion of the
rectum, between the general {883} venous system and that of the liver.
It should be borne in mind that these veins are destitute of valves,
and are situated in a very dependent part, which is normally in a high
degree of functional activity.
External hemorrhoids are found at the very verge of the anus, and, when
not irritated or inflamed, appear like movable, dependent plications of
hypertrophied skin. They appear either singly or in groups, but it is
nothing unusual to find five or six of them together, and they are not
infrequently associated with the internal variety. These pendulous tabs
of integument are very prone to inflammation, and they then become
exquisitely tender, painful tumors, which vary in size from that of a
small pea to that of a pigeon's egg. That portion of the tumor
presenting toward the anus is covered with mucous membrane; the other
is covered with integument; the former is dark-colored, due to
engorgement of its vessels. These, being composed internally of
tortuous, dilated veins which have totally lost their normal
resiliency, bleed freely on section, but after a time they undergo the
following changes: the over-distended vein, of which each is mainly
composed, either becomes obliterated by the encroachment of
inflammatory deposit or its walls give way and the contained blood
escapes; its serum is absorbed, and the tumor now consists of a
blood-clot, the remains of a vessel, inflammatory lymph, a hyperplasia
of connective tissue, mucous membrane, and integument. It undergoes a
still further change by absorption, and remains a permanent pendulous
teat of cutaneous and connective tissue, bearing no trace of vascular
channels.
On account of the extremely sensitive nature of the mucous membrane and
skin of the anus, an inflamed condition of these tumors entails an
amount of suffering very disproportionate to their size: there is
torture in the act of defecation, constant tenesmus, spasm of the
sphincters, a sense of weight and heat in the perineum, and sometimes a
swollen, very painful, condition of the raphé, which stands out like a
cord.
Occasionally there is a total inability to urinate, combined with a
frequent desire to do so. When an attack such as this ends in
suppuration of the tumor a radical cure is effected, but a marginal
ulcer of the anus sometimes follows. An unclean and neglectful habit
provoking constipation, sexual incontinence, over-indulgence in
highly-seasoned food or in stimulating beverages, exposure to cold and
wet, and the straining attendant upon dysuria, will provoke an attack.
No age or sex is exempt from this affection (Gross). It is claimed that
before puberty females are more subject to it than males; after that
age the reverse obtains, except during pregnancy.
Internal hemorrhoids are round, oval, or sometimes cylindroid-shaped
tumors covered by mucous membrane; they are smooth, granular, or rough
to the touch, much less sensitive and painful than the inflamed
external variety, and are situated within the rectum it may be an inch
or two above the internal sphincter muscle. They occur in groups or
scattered over the surface of the bowel. In structure they are soft,
spongy, vascular tumors composed of dilated and tortuous blood-vessels,
the veins predominating over the arteries, their interstices scantily
supplied with connective tissue, and their covering is of mucous
membrane. In color they are dark red, but when compressed and
strangulated by the sphincters they assume a dusky purple hue. After
long exposure they take on a pseudo-cutaneous appearance.
{884} The columns of the rectum are the seat of the cylindroid pile,
which is brighter in color and much more arterial in its structure than
the ordinary variety, and bleeds very freely. Anything which causes
stasis and accumulation of blood in the hemorrhoidal plexus of veins
predisposes to this very common affection. Constipation is the usual
cause; and among others may be named diseases of the liver which cause
portal obstruction, pelvic tumors causing engorgement from pressure,
the gravid uterus, labor, prostatic hypertrophy, urinary calculi,
stricture of the urethra, stricture of the rectum, and rectal tumors.
Among other causes are horseback-riding, the erect posture, violent
cathartics, seat-worms, dysentery, diarrhoea, dyspepsia, and a
sedentary life, with a diet of rich, stimulating food.