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.
Causes of Menstrual Back Pain. There could be three reasons for back pain during the womanâs menstrual cycle. This includes: Dysmenorrhea: When the uterus contracts sharply the result is cramping whether it be in the abdomen, upper thighs or back. This is one of the leading causes of back pain during the menstrual cycle.