The last and most fearful condition of a ture is its state of strangulation, in which the protruded viscus, no longer capable of being returned to its former situation within the ab domen, no longer fit for the performance of its functions, is banded and hound down at its neck in such wise as to interrupt and impair the circulation through it. In order properly to understand this part of the subject, it will be necessary to consider it under three heads: 1. the causes that seem to produce the stran gulation ; 2. its effect on the structures within the hernial sac; 3. its effect on the viscera within the cavity of the abdomen.
1. Of the three natural apertures at which abdominal hernim commonly occur, one, the umbilicus, is unquestionably seated within tendon, and so circumstanced that any con traction of any muscle connected with it, whe ther spasmodic or permanent, must rather ex pand the opening than contract it. Another, the crural ring or canal, is composed of tendon and of bone, and so constructed that although certain positions of the trunk or inferior extre mity might possibly diminish its size, no mus cular action can exert any influence over it. The third, the inguinal canal, is of greater length and more complicated in its construction, and it is a question whether the same pathological condition can be predicated of it, or whether strangulation does not here occasionally occur in consequence of muscular action alone.* Sir A. Cooper seems to acknowledge the possibility of a spasmodic stricture at the internal ring, the strangulation then being effected by a com pression exercised by the inferior edge of the internal oblique and transversalis muscles:I Guthrie speaks of hernire being frequently strangulated by passing between the fibres of the internal oblique, which are separated at the inferior and external border of the muscle above the origin of the cremaster.* Scarps says that " towards the side, at about eight lines distance from the apex of the ring, the lower muscular fibres of the internal oblique muscle separate from each other to allow the spermatic cord to pass between them and again, " the small sac or rudiment of the hernia, not unlike a thimble, when it makes its first appearance under the fleshy margin of the transverse, rests immediately on the anterior surface of the spermatic cord ; it then extends and passes in the middle of the separation formed by the divarication of the inferior fleshy fibres of the internal oblique and of the principal origin of the cremaster muscle."] it must, however, be
conceded that Scarpa did not attribute the strangulation of any form of inguinal hernia to a contraction of these muscular fibres. Now, although it is almost presumptuous to differ from authorities of so high a class, yet I cannot agree either with the opinion that hernia: arc liable to a spasmodic constriction, or with the descriptive anatomy on which such an opinion might be founded.
In about one subject out of every three or four there certainly is a slight divarication or separation of fibres of the external oblique muscle, or rather there is a cellular connexion between the origin of the cremaster muscle and the inferior fibres of the oblique, which is easily separable by the knife ; but the question is, does the spermatic cord in the natural condition, or the hernia in its course to the external ring, pass through or between these fibres ? I believe they do not. I have dissected numerous cases of hernia without observing such a disposition of parts, and I think that if either the spermatic cord or the hernia took such a course, thepro trusion must then come to lie in front of the cremaster muscle—a that has not been hitherto observed. AN hen a hernia is found at the groin, the tendon of the external oblique is somewhat stretched and arched forwards above Poupart's ligament in front of the inguinal canal : the fascia transversalis may be stretched also, and the epigastric artery pulled out of its place and made to approach the lines alba; but the muscles arising from Poupart's liga ment, the internal oblique and transversalis, re main unchanged, and if ever strangulation is effected through their operation it is in the manner suggested by Sir A. Cooper. But it is more simple and perhaps more scientific to place muscular contraction out of the question altogether. The phenomena of strangulation exhihit nothing like the irregularities of spasm: there is no sudden exacerbation, no succeeding relaxation—no alternation of suffering and re lief, no assuagement of symptom from medi cines decidedly antispasmodic; the disease once established goes on with an uninterrupted and certain progression that will not admit of expla nation by a cause sn irregular as spasm.