In this X-ray of the tibial plateau you can see the two tibial spines in the centre of the tibial plateau - they are where the cruciate ligaments attach, but you cannot see that here because the ligaments do not show up on X-ray.
The tibial spine is a raised area of bone in the middle of the tibial plateau, and related to the attachment of the cruciate ligaments.
In this X-ray of the tibial plateau you can see the two tibial spines in the centre of the tibial plateau - they are where the cruciate ligaments attach, but you cannot see that here because the ligaments do not show up on X-ray.