Multifidus (MF) is the largest and most medial of the lumbar paraspinal muscles. Each muscle consists of five separate, overlapping bands that form a triangle as these bands run caudolaterally from the midline.
Attachments
Insertion: spinous process at caudal tip.
Origin: transverse process at mamillary process, iliac crest, and sacrum (polysegmental: 2-4 segments below insertion at spinous process).
Innervation
MF is innervation by a single nerve root — the medial branch of the dorsal ramus.
