Diagnostic ultrasound ( PDFDrive )

480 PART II Abdominal and Pelvic Sonography
A
B
C
FIG. 13.15 Indirect Inguinal Hernia. (A) Long-axis view shows
fat-containing indirect inguinal hernia (oblique arrows) with the
sac anterior to the round ligament (RND LIG) (vertical arrow). (B)
Short-axis view of hernia (arrow) in (A). (C) In another patient,
fat-containing indirect inguinal hernia with narrow neck (arrow).
inguinal hernias, on the other hand, extend into the opened
inguinal canal “indirectly” from a superior and lateral direction.
he conjoined tendon area, and thus the neck of a direct inguinal
hernia, arises inferior and medial to the inferior epigastric vessels
(Fig. 13.21).
he neck of direct inguinal hernias is typically wider than
the fundus. his makes incarceration and strangulation of direct
hernias rare. Most small to medium direct inguinal hernias are
completely reducible, but large direct inguinal hernias may be
incompletely reducible, especially in the upright position. Most
direct inguinal hernias spontaneously reduce completely in the
supine position during quiet respiration, and therefore they are
visible only during Valsalva maneuvers or in the upright
position.
he conjoined tendon consists of the aponeuroses of the
internal oblique and transverse abdominis muscles and the
underlying transversalis (transverse) fascia. It is located inferior
to the lower edge of the external oblique aponeurosis. In most
patients the aponeuroses of the internal oblique and transverse
abdominis muscles are not closely adherent to each other; the
aponeurosis of the transverse abdominis is separated from the
underlying transversalis fascia and peritoneum by a variable layer
of preperitoneal fat; and the conjoined tendon is not well deined
(Fig. 13.22).
hinning and anterior bulging of the conjoined tendon
(conjoined tendon insuiciency) is a precursor to development
of direct inguinal hernias. In males the anterior bulging displaces
and rotates the spermatic cord laterally. he thinning and bulging
of the conjoined tendon push the aponeuroses of the internal
oblique and transverse abdominis muscles closer together, making
the conjoined tendon appear to be a more discrete structure
than when the patient is in the supine position and in quiet
respiration (Figs. 13.23 and 13.24). As the thinning and bulging
progress, a tear can form within the tendon, leading to the formation
of a direct inguinal hernia. Smaller direct inguinal hernias
extend anteriorly into the loor of the inguinal canal, but larger