Final answer:
The fibular head is often used as an anatomical landmark to guide the needle placement when performing a lateral popliteal sciatic nerve block.
Step-by-step explanation:
The anatomical landmark often used to guide the needle placement when performing a lateral popliteal sciatic nerve block is the fibular head. This landmark is located on the lateral side of the proximal tibia and can be palpated. The sciatic nerve runs posterior to the fibular head, making it a useful reference point for needle placement.