A 68-year-old man from Mumbai presents with a long-standing right inguinal hernia. During surgical repair, the surgeon identifies a hernia sac that arises lateral to the inferior epigastric vessels and enters the inguinal canal at the internal ring. The hernia sac contains small bowel loops that are freely reducible. Which of the following structures is most likely to be at risk of injury if the sac is not carefully dissected from the internal spermatic fascia during repair?