<qa>  What is the primary method of spinal anesthesia performed?Traditionally, spinal anesthesia is performed using the palpation of bony landmark to identify the level and point of entry of the spinal needle. Recently, ultrasound imaging has become an increasingly popular procedure among anesthesiologists to guide neuraxial blockade. Most of the studies on pre-procedural ultrasound-guided neuraxial techniques are limited to a midline approach using a transverse median views. The parasagittal oblique view consistently offers better ultrasound view of the neuraxis compared to the transverse median view. However, it is still not evident whether these superior parasagittal oblique views will lead to an easier paramedian needle insertion. In the literature, there are no studies directly comparing the US-guided paramedian approach using the parasagittal oblique PSO view, the US-guided midline approach using the transverse median view, and the conventional landmark midline approach to perform spinal anesthesia in the elderly patients, in particular for the teaching of novice anesthesia residents. 