the scale of measurements drawn up by some eminent
surgeons, with the object of determining the precise relative position
of the several parts of the inguinal region.

The existence of an inguinal canal consisting, as I have described it,
of funnel-shaped elongations from the several inguinal layers continued
over the cord as far as the testicle, renders the adult male especially
liable to hernial protrusions at this part. The oblique direction of the
canal is, in some measure, a safeguard against these accidents; but this
obliquity is not of the same degree in all bodies, and hence some are
naturally more prone to herniae than others.

DESCRIPTION OF THE FIGURES OF PLATES 30 & 31.

PLATE 30.

A. The anterior superior iliac spine.

B. The umbilicus.

C. The spine of the pubis.

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

E. The internal oblique muscle; e, its tendon.

F. The transverse muscle; f, its tendon, forming, with e, the conjoined
tendon.

G. The rectus muscle enclosed in its sheath.

H. The fascia spermatica interna covering the cord; h, its funnel-shaped
extremity.

I, K, L, M. See Plate 31.

N. The femoral artery; n, its profunda branch.

O. The femoral vein.

P. The saphena vein.

Q. The sartorius muscle.

R. The sheath of the femoral vessels.

S. The falciform margin of the saphenous opening.

T. The anterior crural nerve.

U. The pubic portion of the fascia lata.

V. The iliac portion attached to Poupart's ligament.

W. The lower part of the iliacus muscle.

[Illustration: Abdomen and leg, showing blood vessels, muscles
and other internal organs.]
PLATE 30

PLATE 31.

A. The anterior superior iliac spine.

B. The umbilicus.

C. The spine of the pubis.

D. The external oblique muscle; d, its tendon; d*, the external ring.

E. The internal oblique muscle.

F. The transverse muscle; f, its tendon; forming, with e, the conjoined
tendon.

G. The rectus muscle laid bare.

H h. The fascia spermatica interna laid open above and below d*, the
external ring.

I. The peritonaeum closing the internal ring.

K. The fascia transversalis; k, its pubic part.

L. The epigastric artery and veins.

M. The spermatic artery, veins, and vas deferens bending round the
epigastric artery at the internal ring; m, the same vessels below
the external ring.

N. The femoral artery; n, its profunda branch.

O. The femoral vein, joined by--

P. The