Hip bone
![](/Images/godic/202501/20/Hip_bone_anterior_high-res0508.jpg")
![The skeleton of the human pelvis:
2–4. Hip bone (os coxae)
1. Sacrum (os sacrum), 2. Ilium (os ilium), 3. Ischium (os ischii)
4. Pubic bone (os pubis) (4a. corpus, 4b. ramus superior, 4c. ramus inferior, 4d. tuberculum pubicum)
5. Pubic symphysis, 6. Acetabulum (of the hip joint), 7. Foramen obturatum, 8. Coccyx/tailbone (os coccygis)
Dotted. Linea terminalis of the pelvic brim](/Images/godic/202501/20/Skeletal_pelvis-pubis.svg0508.png")
![Plan of ossification of the hip bone. Left hip bone, external surface.](/Images/godic/202501/20/Gray2370508.png")
![The male pelvis, formed by left and right hip bones, sacrum, and coccyx.](/Images/godic/202501/20/Gray2410508.png")
The hip bone (innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three bones: the ilium, ischium, and the pubis.