2.1.12 Key structures: inguinal ligament, femoral triangle
Now we'll move on, and look at the blood vessels and nerves of the hip region. We'll follow the course of the vessels and nerves from the inside of the body, to the proximal part of the thigh. In the next section we'll follow them on down to below the knee. To understand the course of the main blood vessels, the femoral vessels, there's a structure we need to look at, that we saw briefly before, the inguinal ligament; and there's a space between muscles that we need to understand, called the femoral triangle.
Here's the inguinal ligament. It's a strong, tight band that forms the lowest part of the anterior abdominal wall. The inguinal ligament passes from the anterior superior iliac spine, to the pubic tubercle. The inguinal ligament isn't an isolated structure, it's the lower edge of this large sheet of tendon-like material, the external oblique aponeurosis. The inguinal ligament is this part here. The fascia lata, which we've seen already, is attached to it along here.
The gap between the inguinal ligament and the superior pubic ramus is occupied partly by the iliacus and psoas muscles, and partly, as we'll see, by the femoral nerve, artery and vein, and the inguinal lymph nodes. The other muscle in the picture here is obturator externus.
Now let's add all the other thigh muscle to the picture, and see the femoral triangle. Here, the fascia lata has been left intact; here, it's been removed. The femoral triangle is the name given to this deep hollow. It's bounded by sartorius laterally, adductor longus medially, and the inguinal ligament above. In the depths of the triangle pectineus, psoas major and iliacus pass backward toward their insertions.