Background: Using the transverse approach lumbar ultrasound to assess the depth from the skin to ligamentum flavum and to estimate the width of the spinal space vesus the actual distance from the skin to the spinal space on the needle. Design: Clinical trial with 38 parturients. Results: The maternal age is 30 ± 5.46 yr, pregnancy BMI at delivery is 26.73 ± 2.73 kg / m2.