The nerves are compressed and people then experience the symptoms of pain, weakness, and numbness. Other conditions, such as spinal stenosis, spondylolisthesis, or piriformis syndrome can also cause sciatica symptoms by irritating the sciatic nerve.
Related Story: Get to know the Eurovision 2015 finalists. Map: Austria. Swedish singer Mans Zelmerlow has won the 60th Eurovision Song Contest, with Guy Sebastian coming in fifth for wildcard entry Australia.
American Mikaela Shiffrin won for the third successive World Cup in Austria With the 2018 Winter Olympics in Pyeongchang looming next month, BBC Sport brings you a weekly round-up of the big stories in the build-up.