The inguinal ligament is a strong, fibrous band of connective tissue located in the groin area. It plays a role in the structural integrity of the lower abdominal region, pelvis, and upper thigh.
Anatomy and Location
The inguinal ligament extends across the lower abdomen, forming a boundary in the groin. It spans from the anterior superior iliac spine (ASIS) of the pelvis, a bony projection at the front of the hip bone, to the pubic tubercle of the pubic bone, located near the midline. This fibrous band, which is the thickened lower border of the external oblique muscle’s aponeurosis, courses obliquely downwards and inwards.
It forms the superior boundary of the femoral triangle, a triangular depression in the upper thigh. This space allows various structures to pass from the abdomen into the thigh. The inguinal ligament also constitutes the floor of the inguinal canal, a passage in the anterior abdominal wall.
Function and Importance
The inguinal ligament contributes to the structural support of the abdominal wall. It anchors the oblique muscles of the abdomen to the pelvis, providing stability and flexibility to the hips. It supports soft tissues in the groin and maintains the integrity of the inguinal canal.
The ligament also acts as a boundary for structures, protecting nerves and blood vessels as they pass from the trunk into the lower extremities. For instance, the femoral artery and vein, along with the femoral nerve, pass underneath the inguinal ligament to enter the thigh. Its location makes it an anatomical landmark for medical professionals during examinations and surgical procedures.
Related Medical Conditions
Inguinal hernias are a condition where abdominal contents, such as part of the intestine or fat, protrude through weakened areas in the abdominal wall near the ligament. There are two main types: indirect and direct inguinal hernias.
Indirect inguinal hernias occur when abdominal contents push through the deep inguinal ring and into the inguinal canal, often due to an opening that did not close properly after birth. This type is more common in males. Direct inguinal hernias result from a weakening of the abdominal muscles, causing tissue to push directly through a weak spot in the posterior wall of the inguinal canal, typically affecting older men. Both types present as a bulge in the groin, which may cause discomfort or pain, especially with straining.
The inguinal ligament can also be involved in nerve entrapment conditions. The lateral femoral cutaneous nerve, which provides sensation to the outer thigh, can become compressed as it passes near the inguinal ligament, leading to burning pain, tingling, or numbness in the thigh, a condition known as meralgia paresthetica. Similarly, the ilioinguinal nerve can be entrapped, causing pain or altered sensation along the inguinal ligament, groin, and inner thigh.