The sciatic nerve begins in pelvis and normally leaves the pelvis by passing through the greater sciatic foramen below the piriformis muscle. Normally it terminates at the superior angle of the popliteal fossa by dividing into the tibial and common peroneal nerve. However, it may rarely be terminated within the pelvis. In such cases, the tibial nerve and the common peroneal nerve may leave the pelvis through different routes. These variations may cause nerve compressions under other anatomic structures, resulting in non-discogenic sciatica. The aim of present study was to define the relationship between the sciatic nerve and the piriformis muscle. 100 gluteal regions were examined in 50 properly embalmed adult male cadavers. In 96%of the cases, the exit of sciatic nerve from the pelvis was observed as a whole nerve without any division, whereas in 4% of the cases, the tibial branch of the sciatic nerve left the pelvis through the infra piriform foramen and common peroneal branch through the piriformis muscle. The differences in the exit routes of these two nerves are important in clarifying the clinical etiology of non discogenic sciatica.

Objective: The purpose of the present study was to assess the effect of folic acid (folacin) and vitamin B12 (cobalamin) deficiency or supplementation on regulation of the one-carbon metabolism (OCM) in depression in adult male rats. Methods: Fifty adult male Albino rats (Sprague-Dawely) strain, mean weight varied between 160.2 to 163.7 g were fed on basal control diet, folic acid deficient diet (FD), folic acid supplemented diet (100mg folic acid/kg diet) (FS), vitamin B12 deficient diet (B12D), and Vit.B12 supplemented diet (0.5mg vit.B12/kg diet) (B12S) throughout the experimental period (21days). Serum was analyzed for content of folic acid, vitamin B12, homocysteine (Hcy), phospholipids (PL), malondialdehyde (MDA), and reduced glutathione (GSH). Brain was analyzed for serotonin (5-HT), dopamine (DA), and norepinephrine (NE) contents. Results: Serum folic acid, vitamin B12, PL concentrations and brain levels of 5-HT, DA, and NE were reduced significantly (p<0.05) in rats fed diets deficient in folic acid (FD) or vitamin B12 (B12D). Dietary supplementation of folic acid or vitamin B12 resulted in significant increase in these values when compared to control group. Serum Hcy levels were significantly increased (p<0.05) in rats fed diets deficient in either folic acid or vitamin B12. Dietary supplementation of folic acid or vitamin B12 reduced Hcy concentration. Serum MDA levels were significantly increased by feeding FD diet. Folic acid supplementation reduced serum MDA level, while folic acid deficiency resulted in significant reduction in serum GSH content. There were no significant differences in the levels of serum MDA, and GSH in rats fed B12D or B12S diets as compared with control rats. Conclusion: The present study concluded that, folate and vitamin B12 are involved in the one-carbon metabolism necessary for the production of monoamine transmitters and prevention of depression in adult male rats. Also, the deficiency of the vitamins may interfere with methylation reactions.