Yes sciatica can cause numbness, pain and weakness. As a Chiropractor I see a lot of Sciatica, some come with pain, some with numbness, and a few with weakness.
The Sciatic nerve is a thick nerve with many branches. Most think of it as pain down the leg. Sciatica can produce symptoms in the groin, calf, big toe, thigh and buttocks to name a few.
Chiropractic has very effective treatments including Chiropractic adjustment, Avalon Light Therapy, Cold Laser, Myofascial release, exercise, and stretching, depending on the origin of the problem.