Background: Mechanical low back pain (L.B.P) is most common in middle-aged people especially in developing countries and the symptom compromises routine life activities of the patients. Disk herniation is the most frequent cause of LBP. The less costly way for diagnosing the cause of LBP is performing a careful physical examinations. This study aimed to evaluate the sensitivity and specificity of clinical diagnosis of the cause of Discal Sciatic Neuralgia at Construction Labors in comparison to MRI as the gold standard.

Methods: In a descriptive- analytic study 60 middle-aged professional construction workers were evaluated. Their age range was 25-45 years old and all of them had the complaint of mechanical LBP. Medical history was taken and all cases under went a cautious physical examination. The presence of disk herniation between L4-L5 orL5-S1 was recorded according to clinical signs and symptoms. Lumbosacral MRI was performed for all cases and the results were compared to clinical data.

Results: The clinical diagnosis of presence and severity of pathology was confirmed by MRI in all stages of discopathy in L5-S1 and L4-L5 vertebrae (sensitivity= 100%).

Conclusion: This study showed that careful physical examinations will be sufficient for the sciatic neuralgia diagnosis and even the staging of disk herniation can be performed clinically. Requesting MRI as an expensive procedure is not recommended for diagnosis of Discal sciatic neuralgia because of feasibility of the cost effective way of precise physical examination.