The pelvic girdle is directly attached to the vertebral column in the sacral region. The pelvic girdle consists of two similar halves which are known as ossa innominata. Each os innominatum is. formed by three bones. The dorsal bone is known as ilium, antero-Ventral bone is named as pubis and the ventral bone is called ischium. The pelvic girdle has a depression (concavity) at the junction of the three bones. It is known as acetabulum, into which the head of femur of the hind limb articulates.
The same bones are present in all the pelvic girdles of the different vertebrates but have undergone modification.
|Calotes (Garden Lizard)||Columba (Pigeon)||Oryctolagus (Rabbit)|
|1. Pelvic girdle is stout and solid. Ifts well suited for walking habits.||1. Pelvic girdle is large and pneumatic. It is well suited for bipedal locomotion.||1. Pelvic girdle is stout and associates with the vertebral column. It is adopted for swift running.|
|2. Each os innominatum is formed by the ilium, ischium and pubis.||2. Same as in calotes.||2. Each os innominatum is formed by ilium, ischium, pubis and cotyloid cartilage bones.|
|3. The bones are structurally united.||3. The bones are compactly fused.||3. Same as in columba.|
|4. Ilium is strong, rod shaped and is directed upwards.||4. Ilium is long, thin and plate-like bone. It is differentiated into preacetabular and postacetabular regions.||4. Ilium is large and broad. The antero-dorsal edge is raised to form iliac crest.|
|5. Ilium articulates with two sacral vertebrae.||5. Ilium articulates with synsacrum.||5. Anteriorly ilium has articular surface for the sacral vertebrae.|
|6. Ischium is flat, slightly curved and axe-shaped. It is directed downwards and backwards.||6. Ischium a flat bone fused with the post acetabulariiium. They are separated by ilio-ischial foramen.||6. Ischium is broad and slightly curved bone lying behind ilium. It is posterodorsal in position.|
|7. Ilio-ischial foramen is present.||7. llio-ischial foramen is large.||7. Ilio-ischial foramen is absent.|
|8. Ischial tuberosity is absent.||8. It is absent is pigeon.||8. Ischium bears an ischial tuberosity.|
|9. Ischial symphysis is present.||9. It is absent.||9. Ischial symphysis is present.|
|10. Hypoischium is present between the ends of the two ischia.||10. Absent.||10. Absent.|
|11. On the ventral side posteriorly the pubis is formed like a flat elongated and slight ly curved bone, pubis.||11. Pubis is long, slender, curved bone. It lies ventral and parallel with ischial, Pubis.||11. Pubis is flat curved bone directed ventrally pubis symphysis is present. Epipubis is absent.|