Page 79 - Clinical Anatomy

ECA2 7/18/06 6:42 PM Page 64

64 The abdomen and pelvis

Relations
•◊◊Anteriorly — the skin, superficial fascia and the external oblique
aponeurosis cover the full length of the canal; the internal oblique covers its
lateral one-third.
•◊◊Posteriorly — the conjoint tendon forms the posterior wall of the canal
medially, the transversalis fascia laterally. (The conjoint tendon represents
the fused common insertion of the internal oblique and transversus into the
pubic crest and pectineal line.)
•◊◊Above — arch the lowest fibres of the internal oblique and transversus
abdominis.
•◊◊Below—lies the inguinal ligament.
The internal (or deep) ring represents the point at which the spermatic
cord pushes through the transversalis fascia, dragging from it a covering
which forms the internal spermatic fascia. This ring is demarcated medially
by the inferior epigastric vessels passing upwards from the external iliac
artery and vein.
The external (or superficial) ring is a V-shaped defect in the external
oblique aponeurosis and lies immediately above and medial to the pubic
tubercle. As the cord traverses this opening, it carries the external spermatic
fascia from the ring’s margins.
The inguinal canal transmits the spermatic cord and the ilio-inguinal
nerve in the male and the round ligament and ilio-inguinal nerve in the
female.
The spermatic cord comprises (Fig. 46):
•◊◊three layers of fascia— the external spermatic, from the external oblique
aponeurosis; the cremasteric, from the internal oblique aponeurosis (con-
taining muscle fibres termed the cremaster muscle); the internal spermatic,
from the transversalis fascia;
•◊◊three arteries—the testicular (from the aorta); the cremasteric (from the
inferior epigastric artery); the artery of the vas (from the inferior vesical
artery);
•◊◊three veins—the pampiniform plexus of veins, (draining the right testis
into the inferior vena cava and the left into the left renal vein), and the cre-
masteric vein and vein of the vas, which accompany their corresponding
arteries.
•◊◊three nerves — the nerve to the cremaster (from the genito-femoral
nerve); sympathetic fibres from T10–11 spinal segments; the ilio-inguinal
nerve (strictly, on and not in the cord);

Fig. 46◊Scheme of the
spermatic cord and its
contents, in transverse
section.