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.
What Causes Back Muscle Pain? Most causes of low back pain are muscle, ligament or joint related. Commonly, these back injuries are caused by muscular strains, ligament sprains and joint dysfunction, particularly when pain arises suddenly during or following physical loading of your spine.