This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The conjoined tendon is prolonged outward from the edge of the rectus muscle two-thirds of the distance to the epigastric artery, and sometimes more. A direct hernia piercing the abdominal wall to the inside of the hypogastric artery (very rare) will push in front of it the peritoneum, subperitoneal fat, transversalis fascia, conjoined tendon, and intercolumnar fascia, making its exit at the inner side of the external abdominal ring. The common site is just to the outer side of the obliterated hypogastric artery, and it pushes in front of it the conjoined tendon and intercolumnar fascia, and makes its appearance at the outer side of, or through, the external abdominal ring (Fig. 400). If it pierces the middle inguinal fossa farther out, and just to the inside of the epigastric artery, it passes to the outside of the conjoined tendon, and is covered instead by the cremaster muscle. Division of the stricture which occurs here must be made upward and inward, because to its outer side lie the epigastric vessels.
Fig. 400. - Direct inguinal hernia.
When the conjoined tendon is sufficiently thick and strong it is brought down and sewed to Poupart's ligament beneath and behind the cord, thus closing the hernial opening. When it is very weak and thin, the edge of the rectus muscle is dragged downward and outward and sewed to Poupart's ligament (Bloodgood), then the conjoined tendon (Fig. 401) is brought down in front of it and sewed to Poupart's ligament, and the external ring narrowed so as to allow room only for the cord to escape (Fig. 402). (The triangular fascia, page 377, is too uncertain and insignificant a structure to be considered in inguinal herniae).
Fig. 401. - The conjoined tendon of the internal oblique and transversalis muscles.
Fig. 402. - Radical cure of direct inguinal hernia. The aponeurosis of the external oblique has been divided and drawn back. The conjoined tendon has been drawn upward toward the median line. The transversalis fascia covering the rectus has been incised and the edge of the muscle has been drawn out and down and sewed to the edge of Poupart's ligament (Bloodgood). The operation is completed by sewing the conjoined tendon to Poupart's ligament, replacing the cord on it, and stitching the edges of the external oblique together down to the external ring.