For a sport hernia, the anatomic defect is actually located on the inguinal floor between the conjoint tendon and the inguinal ligament. The floor should be a solid tendon/muscle layer. However, due to thinning of the inguinal floor from an acute tear or chronic stretching of the tissues, it is no longer able to support the external pressure created by the core muscles tightening during sports. The intestines and abdominal fat push forward, creating a bulge in the inguinal crease during activity. This bulge in the floor then disappears when the core is not contracted. While this bulge is not a danger for the patient, it constantly hits and irritates the nerves in the inguinal canal. This produces pain and can limit the athlete from his or her maximal ability.
While the inguinal floor is truly weakened, it remains intact; therefore, the intestines are not pushing through a hole as in a true inguinal hernia. This is the key difference between the two.
The term core muscle injury is used, it is referring to the muscles as they attach to the pubic bone. The sport hernia at the inguinal floor is part of that complex but also includes the adductor tendon, the rectus abdominis muscle, and the common adductor- rectus abdominis aponeurotic plate.