This study was performed to assess the factor affecting the distance from skinto epidural space.

The distance from the skin to epidural space(DSES) was measured in 105 patients who received lumbar epidural anesthesia. The relationship between patient factors [age, weight, height, body mass index(BMI : weight/height²), pregnancy] and technical factor(posture) versus DSES was investigated using multiple regression analysis.

The mean DSES was 4.5±0.7cm. DSES correlated positively with weight and BMI in non-obstetrics(including male), and BMI in obstetrics. But, DSES did not correlated with posture.

The patient's weight and BMI in non-obstetrics and BMI in obstetrics but posture during epidural needle placement are important factors influencing DSES.