Table 1.

Frequencies of the needle reaching a bony landmark and lumbar multifidus (LM) muscle using ultrasound imaging (n = 20).

	Method 1 (2 cm from Spinous Process, 20° Angle)		Method 2 (4 cm from Spinous Process, 45° Angle)
	at L4	at L5	at L4	at L5
Reaching bony landmark, count (%)
Absence of bony drop Lamina Junction of lamina and spinous process Spinous process	1 (5%) 14 (70%) 3 (15%) 2 (10%)	0 (0%) 14 (70%) 1 (5%) 5 (25%)	1 (5%) 14 (70%) 1 (5%) 4 (20%)	3 (15%) 15 (75%) 2 (10%) 0 (0%)
Research lumbar multifidus, count (%)
Reaching deep LM Reaching superficial LM Did not reach	19 (95%) 1 (5%) 0 (0%)	19 (95%) 1 (5%) 0 (0%)	17 (85%) 2 (10%) 1 (5%)	19 (95%) 0 (0%) 1 (5%)
Length (mm) of needle subcutaneously, mean ± SD (range)	53 ± 19 (11–100)	58 ± 16 (33–100)	55 ± 18 (24–88)	67 ± 19 (45–100)