Corpus: Hip bone
1. Definition
2. Anatomy
Both hip bones are connected posteriorly to the sacrum via an amphiarthrosis, the sacroiliac joint (articulatio sacroiliaca), which is relevant for the suspension of the spinal column. Anteriorly, the two hip bones are connected to the pelvic symphysis (symphysis pubica).
3. Development
In total, the hip bone develops from three centers of ossicifation (anlage): one anlage develops in the 3rd fetal month in the ilium, another anlage between the 4th and 5th fetal month in the ischium and within the 5th and 6th fetal month the third anlage in the pubic bone. The fusion of these three anlagen takes place in the centre of the acetabulum in a Y-shaped figure. In addition, one or more separate bone nuclei (ossa acetabuli) develop in the acetabulum in the 10th to 12th year of life. The three parts of the hip bone synostose between the ages of 5 and 7, but not within the acetabulum until the age of 15 to 16. Epiphyseal bone anlagen can be found on the spines (16 years of age), on the ischial tuberosity (13 to 15 years of age) and on the iliac crest (13 to15 years of age).