Inferior pubic ramus

The inferior pubic ramus is a part of the pelvis and is thin and flat.

It passes laterally and downward from the medial end of the superior ramus; it becomes narrower as it descends and joins with the inferior ramus of the ischium below the obturator foramen.

Surfaces

Its anterior surface is rough, for the origin of muscles—the gracilis along its medial border, a portion of the Obturator externus where it enters into the formation of the obturator foramen, and between these two, the adductores brevis and magnus, the former being the more medial.

The posterior surface is smooth, and gives origin to the obturator internus, and, close to the medial margin, to the Constrictor urethrae.Borders

In the female pelvis, the medial border is thick, rough, and everted, and presents two ridges, separated by an intervening space.

The ridges extend downwards, and are continuous with similar ridges on the inferior ramus of the ischium; to the external ridge is attached the fascia of Colles to the internal ridge is attached the inferior fascia of the urogenital diaphragm

The lateral border is thin and sharp, forms part of the circumference of the obturator foramen, and gives attachment to the obturator membrane.