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The Distinctive Diagnosis Between External And Internal Inguinal Herniae The Taxis The Seat Of Stricture And The Operation

Sources: Surgical Anatomy

A comparison of the relative position of these two varieties of herniae

is in ordinary cases the chief means by which we can determine their

distinctive diagnosis; but oftentimes they are found to exhibit such an

interchange of characters, that the name direct or oblique can no longer

serve to distinguish between them. The nearer the one approaches the

usual place of the other, the more likely are they to be mistaken the

> one for the other. An internal hernia may enter the inguinal canal, and

become oblique; while an external hernia, though occupying the canal,

may become direct. It is only when these herniae occur at the situations

commonly described, and where they manifest their broadest contrast,

that the following diagnostic signs can be observed.

The external bubonocele, H, Plate 37, G, Plate 38, when recently formed,

may be detected at a situation midway between the iliac and pubic

spinous processes, where it has entered the internal ring. When the

hernia extends itself from this part, its course will be obliquely

inwards, corresponding with the direction of the inguinal canal. While

it still occupies the canal without passing through the external ring,

it is rendered obscure by the restraint of the external oblique tendon;

but yet a degree of fulness may be felt in this situation. When the

hernia has passed the external ring, T, Plate 36, it dilates

considerably, and assumes the form of an oblong swelling, H, Plate 36,

behind which the spermatic vessels are situated. When it has become

scrotal, the cord will be found still on its posterior aspect, while the

testicle itself occupies a situation directly below the swelling.

The internal hernia, H, Plate 38, also traverses the external ring, T,

where it assumes a globular shape, and sometimes projects so far

inwards, over the pubes, C, as to conceal the crista of this bone. As

the direction of this hernia is immediately from behind forwards, the

inguinal canal near the internal ring is found empty, unswollen. The

cord, Q, lies external to and somewhat over the fore part of this

hernia; and the testicle does not occupy a situation exactly beneath the

fundus of the sac, (as it does in the external hernia,) but is found to

be placed either at its fore part or its outer side. This difference as

to the relative position of the cord and testicle in both these forms of

herniae, is accounted for under the supposition that whilst the external

variety descends inside the sheaths of the inguinal canal, the internal

variety does not. But this statement cannot apply to all cases of

internal hernia, for this also occasionally enters the canal. Both forms

of inguinal herniae may exist at the same time on the same side: the

external, G, Plate 38, being a bubonocele, still occupying the inguinal

canal; while the internal, H, protrudes through the external ring, T, in

the usual way. In this form of hernia--a compound of the oblique and

direct--while the parts remain still covered by the integuments, it must

be difficult to tell its nature, or to distinguish any mark by which to

diagnose the case from one of the external variety, H, Plate 36, which,

on entering the canal at the internal ring, protrudes at the external

ring. In both cases, the swelling produced in the groin must be exactly

of the same size and shape. The epigastric artery in the case where the

two herniae co-exist lies between them, holding in its usual position

with respect to each when occurring separately--that is, on the outer

side of the internal hernia, H, and on the inner side of the external

one, G; and the external hernia, G, not having descended the canal as

far as the external ring, T, allows the internal hernia, H, to assume

its usual position with respect to the cord, Q. [Footnote]

[Footnote: Cases of this double hernia (external and internal) have been

met with by Wilmer, Arnaud, Sandifort, Richter, and others. A plurality

of the same variety of hernia may also occur on the same side. A

complete and incomplete external inguinal hernia existing in the one

groin, is recorded by Mr. Aston Key in his edition of Sir Astley

Cooper's work on Hernia. Sir Astley Cooper states his having met with

three internal inguinal herniae in each inguinal region. (Ing. et

Congenit. Hernire.) ]

Returning, however, to the more frequent conditions of inguinal

hernia--viz., those in which either the direct or the oblique variety

occurs alone--it should be remembered that a hernia originally oblique,

H, Plates 35 and 37, may, when of long standing, and having attained a

large size, destroy, by its gravitation, the obliquity of the inguinal

canal to such a degree as to bring the internal, H, Plate 35, opposite

to the external ring, as at I, and thereby exhibit all the appearance of

a hernia originally direct, I, Plate 37. In such a case, the epigastric

artery, F, which lies on the outer side of the neck of a truly direct

hernia, I, Plate 37, will be found to course on the inner side, G, of

the neck of this false-seeming direct hernia, I, Plate 35.

In the trial made for replacing the protruded bowel by the taxis, two

circumstances should be remembered in order to facilitate this object:

1st, the abdominal parietes should be relaxed by supporting the trunk

forward, and at the same time flexing the thigh on the trunk; 2nd, as

every complete hernial protrusion becomes distended more or less beyond

the seat of stricture--wherever this may happen to be--its reduction by

the taxis should be attempted, with gradual, gentle, equable pressure,

so that the sac may be first emptied of its fluid. That part of the

hernia which protruded last should be replaced first. The direction in

which the hernia protrudes must always determine the direction in which

it is to be reduced. If it be the external or oblique variety, the

viscus is to be pushed upwards, outwards, and backwards; if it be the

internal or direct variety, it is to be reduced by pressure, made

upwards and backwards. Pressure made in this latter direction will serve

for the reduction of that hernia which, from being originally external

and oblique, has assumed the usual position of the internal or direct


The seat of the stricture in an external inguinal hernia is found to be

situated either at the internal ring, corresponding to the neck of the

sac, or at the external ring. Between these two points, which "bound the

canal," and which are to be regarded merely as passive agents in causing

stricture of the protruding bowel, the lower parts of the transversalis

and internal oblique muscles embrace the herniary sac, and are known at

times to be the cause of its active strangulation or spasm.

The seat of stricture in an internal hernia may be either at the neck of

its sac, I, Plate 37, or at the external ring, T, Plate 38; and

according to the locality where this hernia enters the inguinal wall,

the nature of its stricture will vary. If the hernia pass through a

cleft in the conjoined tendon, f, Plate 38, this structure will

constrict its neck all around. If it pass on the outer margin of this

tendon, then the neck of the sac, bending inwards in order to gain the

external ring, will be constricted against the sharp resisting edge of

the tendon. Again, if the hernia enter the inguinal wall close to the

epigastric artery, it will find its way into the inguinal canal, become

invested by the structures forming this part, and here it may suffer

active constriction from the muscular fibres of the transverse and

internal oblique or their cremasteric parts. The external ring may be

considered as always causing some degree of pressure on the hernia which

passes through it.

In both kinds of inguinal herniae, the neck of the sac is described as

being occasionally the seat of stricture, and it certainly is so; but

never from a cause originating in itself per se, or independently of

adjacent structures. The form of the sac of a hernia is influenced by

the parts through which it passes, or which it pushes and elongates

before itself. Its neck, H, Plate 37, is narrow at the internal ring of

the fascia transversalis, because this ring is itself narrowed; it is

again narrowed at the external ring, T, Plate 36, from the same cause.

The neck of the sac of a direct hernia, I, Plate 37, being formed in the

space of the separated fibres of the conjoined tendon, or the pubic part

of the transversalis fascia, while the sac itself passes through the

resisting tendinous external ring, is equal to the capacities of these

outlets. But if these constricting outlets did not exist, the neck of

the sac would be also wanting. When, however, the neck of the sac has

existed in the embrace of these constricting parts for a considerable

period--when it suffers inflammation and undergoes chronic

thickening--then, even though we liberate the stricture of the internal

ring or the external, the neck of the sac will be found to maintain its

narrow diameter, and to have become itself a real seat of stricture. It

is in cases of this latter kind of stricture that experience has

demonstrated the necessity of opening the sac (a proceeding otherwise

not only needless, but objectionable) and dividing its constricted neck.

The fact that the stricture may be seated in the neck of the sac

independent of the internal ring, and also that the duplicature of the

contained bowel may be adherent to the neck or other part of the

interior, or that firm bands of false membrane may exist so as to

constrict the bowel within the sac, are circumstances which require that

this should be opened, and the state of its contained parts examined,

prior to the replacement of the bowel in the abdomen. If the bowel were

adherent to the neck of the sac, we might, when trying to reduce it by

the taxis, produce visceral invagination; or while the stricture is in

the neck of the sac, if we were to return this and its contents en masse

(the "reduction en bloc") into the abdomen, it is obvious that the bowel

would be still in a state of strangulation, though free of the internal

ring or other opening in the inguinal wall.

The operation for the division of the stricture by the knife is

conducted in the following way: an incision is to be made through the

integuments, adipous membrane, and superficial fascia, of a length and

depth sufficient to expose the tendon of the external oblique muscle for

an inch or so above the external ring; and the hernia for the same

extent below the ring. The length of the incision will require to be

varied according to circumstances, but its direction should be oblique

with that of the hernia itself, and also over the centre of its

longitudinal axis, so as to avoid injuring the spermatic vessels. If the

constriction of the hernia be caused by the external ring, a director is

to be inserted beneath this part, and a few of its fibres divided. But

when the stricture is produced by either of the muscles which lie

beneath the aponeurosis of the external oblique, it will be necessary to

divide this part in order to expose and incise them.

When the thickened and indurated neck of the sac is felt to be the cause

of the strangulation, or when the bowel cannot be replaced, in

consequence of adhesions which it may have contracted with some part of

the sac, it then becomes necessary to open this envelope. And now the

position of the epigastric artery is to be remembered, so as to avoid

wounding it in the incision about to be made through the constricted

neck of the sac. The artery being situated on the inner side of the neck

of the sac of an oblique hernia, requires the incision to be made

outwards from the external side of the neck; whereas in the direct

hernia, the artery being on its outer side, the incision should be

conducted inwards from the inner side of the neck. But as the external

or oblique hernia may by its weight, in process of time, gravitate so

far inwards as to assume the position and appearance of a hernia

originally direct and internal, and as by this change of place the

oblique hernia, becoming direct as to position, does not at the same

time become internal in respect to the epigastric artery,--for this

vessel, F, Plate 35, has been borne inwards to the place, G, where it

still lies, internal to the neck of the sac, and since, moreover, it is

very difficult to diagnose a case of this kind with positive certainty,

it is therefore recommended to incise the stricture at the neck of the

sac in a line carried directly upwards. (Sir Astley Cooper.) It will be

seen, however, on referring to Plates 32, 33, 34, 35, 36, 37, & 38, that

an incision carried obliquely upwards towards the umbilicus would be

much more likely to avoid the epigastric artery through all its varying




A. Anterior superior spine of the ilium; a, indicates the situation of

the middle of Poupart's ligament.

B. Symphysis pubis.

C. Rectus abdominis muscle covered by the fascia transversalis.

D. The peritonaeum lining the groin.

E. The situation of the conjoined tendon resisting the further progress

of the external hernia gravitating inwards.

F. A dotted line indicating the original situation of the epigastric

artery in the external hernia.

G. The new position assumed by the epigastric artery borne inwards by

the weight of the old external hernia.

H. The original situation of the neck of the sac of the external hernia.

I. The new situation assumed by the neck of the sac of an old external

hernia which has gravitated inwards from its original place at H.

K. The external iliac vein covered by the peritonaeum.

L. The external iliac artery covered by the peritonaeum and crossed by

the spermatic vessels.

M. The psoas muscle supporting the spermatic vessels and the

genito-crural nerve.

N. The iliacus muscle.

O. The transversalis fascia lining the transverse muscle.

Abdomen, showing bone, blood vessels, muscles<br />
<br />
and other internal organs


A. Anterior superior iliac spinous process.

B. The navel.

C. The situation of the crista pubis.

D. The external oblique muscle; d, its tendon.

E. Internal oblique muscle; e, its tendon, covering the rectus muscle.

F. Lower part of the transverse muscle; f, the conjoined tendon.

G. The transversalis fascia investing the upper part of the hernial sac;

g, the original situation of the epigastric artery internal to this

hernia; g*, the new situation of the artery pushed inwards.

H. The hernial sac, invested by h, the elongation of the fascia

transversalis, or funnel-shaped sheath.

I. The femoral artery.

K. The femoral vein.

L. The sartorius muscle.

M. Iliac part of the fascia lata joining Poupart's ligament.

N. Pubic part of the fascia lata.

O. Saphena vein.

P P. Falciform margin of the saphenous opening.

Q. See Plate 38.

R. Sheath of the femoral vessels.

S. Anterior crural nerve.

T. The external ring.

Abdomen and leg, showing blood vessels, muscles<br />
<br />
and other internal organs


All the letters except the following indicate the same parts as in Plate


F. The epigastric artery passing between the two hernial sacs

G. The umbilical ligament.

H. The neck of the sac of the external hernia.

I. The neck of the sac of the internal hernia.

Abdomen, showing blood vessels, muscles<br />
<br />
and other internal organs


All the letters, with the exception of the following, refer to the same

parts as in Plate 36.

G. The funnel-shaped elongation of the fascia transversalis receiving g,

the sac of the external bubonocele.

H. The sac of the internal inguinal hernia invested by h, the

transversalis fascia.

Q. The spermatic vessels lying on the outer side of H, the direct

inguinal hernia.

Abdomen and leg, showing blood vessels, muscles<br />
<br />
and other internal organs