Not one of Jesus’ bones are broken. That’s a sign that He is the true Passover Lamb whose blood protects us from the angel of death.
It is also a sign of his righteousness. According to Psalm 34, the righteous are afflicted often, but always rescued (v. 19). While the wicked are slain and condemned and slain (v. 21), the righteous survive with all their bones. Not one of them is broken (v. 20). Jesus’ intact bones are a witness to His righteousness, a signal of His ultimate justification.
Behind this is the biblical distinction of flesh and bones. There is no guarantee that the Lord will preserve the flesh of the righteous will be preserved. Flesh is vulnerable, subject to life’s slings. But in the midst of those assaults, the Lord preserves the bones of the righteous, and does not abandon the soul of the righteous to Sheol (Psalm 16).