The inguinal ligament is a paired fibrous cord of connective tissue located at the bottom corners of the abdominal region on each side of mid line of abdomen. It originates from the anterior-superior spine of the ilium. Then it extends medially, traveling obliquely down to be inserted into the spine of pubic bone. It is situated slightly below the inguinal canal. The inguinal ligament constitutes the thickened lower portion of the aponeurosis of the external oblique muscle of abdomen.
In medicine, it is used as an anatomical boundary, or landmark, for the main artery supplying the lower limb, which is the external iliac/femoral artery. It is also the boundary for the main vein draining it, and main nerve supplying the muscles of thigh and leg. It means that all three of them, which are wrapped in the femoral sheath, change their names as they run down beneath and beyond the inguinal ligament. For example, the external iliac artery becomes the femoral artery as it travels down beyond the inguinal ligament, and the femoral vein becomes the external iliac vein as it leaves the thigh running into the lower abdomen.
Below, schematic drawing of the inguinal region and thigh, showing the main arteries and muscles as well as the inguinal ligament.
