On average among OECD countries, there are about 14 students. per teacher at the secondary level (Table D2.2). As the differences in student-teacher ratios indicate, there are fewer full-time equivalent students per full-. time equivalent teachers at the secondary level than at the primary level of education.
Causes of Lower Back Pain. Home/Conditions/Causes of Lower Back Pain. Pain in the lower back has a multitude of causes. The discs, facets, pars interarticularis, sacroiliac joints, hip joints and nerves can all cause a form of lower back pain.
While back pain is often caused by a disease or disorder, many different physical injuries can also result in severe and long-lasting back pain. Some common examples of physical causes include car accidents and sports injuries, or even over-exertion from lifting heavy objects. See also: chronic pain.