nd relative position of the spermatic vessels; but
these, as well as the hernia, still occupy the inguinal canal, and are
invested by the spermatic fascia, 3, 3. When an internal hernia, Fig. 1,
Plate 42, enters the inguinal canal, it also may descend the cord as far
as the testicle, and assume in respect to this gland the same position
as the external hernia. [Footnote]

[Footnote: As the external hernia, Fig. 4, Plate 42, may displace the
epigastric artery inwards, so may the internal hernia, Fig. 1, Plate 42,
displace the artery outwards. Mr. Lawrence, Sir Astley Cooper, Scarpa,
Hesselbach, and Langenbeck, state, however, that the internal hernia
does not disturb the artery from its usual position three-fourths of an
inch from the external ring.]

[Illustration: Abdomen and scrotum, showing bone, blood vessels
and other internal organs.]
Plate 42--Figure 4

PLATE 42, Figs. 5, 6, 7.--The form and position of the inguinal canal
varies according to the sex and age of the individual. In early life,
Fig. 6, the internal ring is situated nearly opposite to the external
ring, 4. As the pelvis widens gradually in the advance to adult age,
Fig. 5, the canal becomes oblique as to position. This obliquity is
caused by a change of place, performed rather by the internal than the
external ring. [Footnote] The greater width of the female pelvis than of
the male, renders the canal more oblique in the former; and this,
combined with the circumstance that the female inguinal canal, Fig. 7,
merely transmits the round ligament, 14, accounts anatomically for the
fact, that this sex is less liable to the occurrence of rupture in this
situation.

[Footnote: M. Velpeau (Nouveaux Elemens de med. Operat.) states the
length of the inguinal canal in a well-formed adult, measured from the
internal to the external ring, to be 1-1/2 or 2 inches, and 3 inches
including the rings; but that in some individuals the rings are placed
nearly opposite; whilst in young subjects the two rings nearly always
correspond. When, in company with these facts, we recollect how much the
parts are liable to be disturbed in ruptures, it must be evident that
their relative position cannot be exactly ascertained by measurement,
from any given point whatever. The judgment alone must fix the general
average.]

[Illustration: Abdomen and scrotum, showing bone, blood vessels
and other internal organs.]
Plate 42--Figure 5

[Illustration: Abdomen and scrotum