The pelvis is a bony structure in the lower part of the trunk, composed of two halves called innominate bones or os coxae. Each innominate bone is made up of three fused bones: the ilium, ischium, and pubis.
Therefore, "hemipelvis" refers to:
* Either the right or left half of the pelvis, including the ilium, ischium, and pubis on that side.
* Sometimes, it may refer to just the ilium, as the ilium makes up the largest part of the innominate bone.
It's important to note that the context of the conversation will usually clarify which specific meaning of "hemipelvis" is intended.