al inguinal hernia are (as to number)
variously described by authors. Thus with respect to the conjoined
tendon, the hernia is said, in some instances, to take an investment of
this structure; in others, to pass through a cleft in its fibres; in
others, to escape by its outer margin. Again, the cremaster muscle is
stated by some to cover this hernia; by others, to be rarely met with,
as forming one of its coverings; and by others, never. Lastly, it is
doubted by some whether this hernia is even covered by a protrusion of
the fascia transversalis in all instances. [Footnote]

[Footnote: Mr. Lawrence (Treatise on Ruptures) remarks, "How often it
may be invested by a protrusion of the fascia transversalis, I cannot
hitherto determine." Mr. Stanley has presented to St. Bartholomew's
Hospital several specimens of this hernia invested by the fascia.
Hesselbach speaks of the fascia as being always present. Cloquet
mentions it as being present always, except in such cases as where, by
being ruptured, the sac protrudes through it. Langenbeck states that the
fascia is constantly protruded as a covering to this hernia: "Quia
hernia inguinalis interna non in canalis abdominalis aperturam internam
transit, tunicam vaginalem communem intrare nequit; parietem autem
canalis abdominalis internum aponeuroticum, in quo fovea inguinalis
interna, et qui ex adverso annulo abdominali est, ante se per annulum
trudit." (Comment, ad illust. Herniarum, &c.) Perhaps the readiest and
surest explanation which can be given to these differences of opinion
may be had from the following remark:--"Culter enim semper has partes
extricat, quae involucro adeo inhaerent, ut pro lubitu musculum
(membranam) efformare queas unde magnam illam inter anatomicos
discrepantiam ortam conjicio." (Camper. Icones Herniarum.)]

The variety in the number of investments of the internal inguinal hernia
(especially as regards the presence or absence of the conjoined tendon
and cremaster) appears to me to be dependent, 1st, upon the position
whereat this hernia occurs; 2nd, upon the state of the parts through
which it passes; and 3rd, upon the manner in which the dissection
happens to be conducted.

The precise relations which the internal hernia holds in respect to the
epigastric and spermatic vessels are also mainly dependent (as in the
external variety) upon the situation where it traverses the groin. The
epigastric artery courses outside the neck of its sac, sometimes i