**2.1 Osseous anatomy**

The pelvis is the bony structure that transmits the weight of the upper axial skeleton to both the lower extremities via hip joint [1–5]. It comprises of the sacrum and three bones on each side that coalesce during adolescence to form the innominate bone of the adult pelvis. The iliosacral joint connects the sacrum to ilium. The ilium becomes the pubis anteriorly and the ischium inferiorly. Two pubic bones are connected to one another via the symphysis.
