The pubis (also known as the pubic bone, Latin: os pubis) is a paired bone that forms the anterior part of the hip bone and the anterior and inferior boundary of the obturator foramen. The left and right pubic bones join at the pubic symphysis.
Each pubic bone has three parts:
- body of the pubis,
- inferior ramus of the pubis, and
- superior ramus of the pubis.
The body of the pubis is the part that forms the anterior one-third of the acetabulum.
The inferior ramus is the portion of the pubic bone that extends downwards and merges with the ramus of the ischium.
The superior ramus of the pubis is the portion extending anteriorly from the body of the pubic bone. The superior ramus of the pubic bone features the following landmarks:
- pecten pubis,
- pubic tubercle,
- obturator groove,
- symphysial surface of the pubis.
The pecten pubis (or the pectineal line) is a sharp, bony ridge on the superior ramus of the pubis, which passes to the pubic tubercle as the continuation of the arcuate line. The pecten pubis serves as the origin site for the pectineus muscle.
The pubic tubercle is a bony prominence on the upper border of the medial part of the superior ramus of the pubis, where the inguinal ligament attaches.
The obturator groove is a deep sulcus on the inner surface of the superior ramus of the pubis above the acetabulum.
The symphysial surface of the pubis is the site where the superior ramus of the pubis continues as the inferior ramus.