1] During the evolution of bipedal gait and erect posture, the lumbosacral part of vertebral column has undergone maximum modifications leading to the development of Lumbosacral angle (LSA).
According to Datta (2008) , the prominence of Lumbosacral angle is due to more extensive anterior surface of the body of fifth lumbar vertebra and the intervertebral disc between L5 and S1, which is much thicker in front than behind.
Lumbosacral angle was measured by goniometer (Fig 2).
It is same as the lumbosacral angle measured by Ferguson's technique in the present study.
In their opinion, the lumbosacral angle measurement is significant in the evaluation of instability and low back pain in 3rd to 6th decades of life.
Hughton et al (2015)  while investigating the relationship between Lumbosacral Angle (LSA) and chronic low back pain (LBP) among females, have found significant positive correlations between degree of LSA and ageing; chronic LBP intensity; and LBP related functional limitation.
Stagnara et al (1982) have measured the lumbosacral angle and found it to be 210 (range 10[degrees]-35[degrees]).