[3] The lacunar ligament is the part of the aponeurosis of the external oblique muscle that is reflected backward and laterally and is attached to the pectineal line of the pubis.

long, larger in the male than in the female, almost horizontal in direction in the erect posture, and of a triangular form with the base directed laterally.

Its base is concave, thin, and sharp, and forms the medial boundary of the femoral ring.

Care must be taken when doing so as up to 25% of people have an aberrant obturator artery (corona mortis) which can cause significant bleeding.

[5] This article incorporates text in the public domain from page 412 of the 20th edition of Gray's Anatomy (1918)