What does hemisacralization of l5 mean?

Didn't fully form: Your bottom lumbar level didn't fully form (or separate from the sacrum) when you were developing. One of the transverse processes (bone that sticks out to the side), either on the left or right, is still fused (connected) with the sacrum. This means this level is either not moving at all (like a surgical fusion) or very little. These discs typically look underdeveloped but otherwise normal.