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 pain between the back, hips and knees include sciatica, inflamed bursas at the hip, dislocation of the hip joint and fractures of the hip and thigh bones. If a person's back and hip muscles are tight, it will induce pain in those regions as well as at the knees.