OBJECTIVE: The purpose of this work is to review the posterior lumbar muscle anatomy, evince the correlation between the anatomy in the axial plane of the MRI and measure the distance from the medium line to the intermuscular plane, between the multifidus and the longissimus in the lower lumbar levels. METHODS: Using the OSIRIX program for Mac, bilateral measurements of the distance from the medium line to the intermuscular plane between the multifidus and longissimus muscles have been performed in the L3/L4, L4/L5 and L5/S1 levels, in 50 adult patients divided equally by gender. RESULTS: This study brings to the conclusion that there is an average distance of 2.42 cm in L3/L4, of 3.13 cm in L4/L5 and of 3.77 cm in L5/S1 when not separated by gender. The average distance increases in the craniocaudal direction in the lower lumbar levels and there is no statistically significant difference toward the gender in levels L4/L5 and L5/S1. CONCLUSION: We conclude that the MRI allows the surgeon to measure the distance from the midline until the intermuscular plane between the multifidus and longissimus and consider it important for the preoperative planning of minimally invasive approaches.
Magnetic resonance imaging; Measures; Anatomy; Surgical procedures, minimally invasive; Arthrodesis
