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.
Ankylosing Spondylitis 101. AS mainly affects the spine and sacroiliac joints (places where the spine joins the pelvis). Inflammation in these areas can cause back and hip pain and stiffness. Eventually, long-lasting inflammation may lead some bones of the spine, called vertebrae, to fuse together. This makes the spine less flexible and may lead to a stooped-over posture.