The definition of asinine is to be silly, stupid or ridiculous. An example of asinine is a foolish prank played on a friend.
In humans, there are twelve thoracic vertebrae and they are intermediate in size between the cervical and lumbar vertebrae; they increase in size going towards the lumbar vertebrae, with the lower ones being a lot larger than the upper.
The cervical vertebrae are C1 - C7. The thoracic vertebrae are T1 - T12. The lumbar vertebrae are L1 - L5. The sacrum and coccyx do not have numbers and each is thought of as one bone.