Multifidus Muscle, Gross Anatomy

Description

Posteriorly, the multifidus muscle is exposed as a series of short, obliquely oriented fascicles spanning from the sacrum and posterior superior iliac region to the spinous processes of the lumbar, thoracic, and lower cervical vertebrae. Deep to the trapezius and latissimus dorsi, the multifidus occupies the groove immediately lateral to the spinous processes, lying medial to the longissimus and iliocostalis components of erector spinae. Segmental bundles run superomedially from transverse and mammillary processes to more superior spinous processes, creating a layered appearance across multiple vertebral levels. Small, dense fibers. Big implications. Clinically, this posterior overview is the one you want when teaching why lumbar stability is not synonymous with “back extensors” in general, because multifidus provides short-lever control of intersegmental motion rather than gross extension torque. Atrophy and fatty infiltration of lumbar multifidus are common after acute low back pain and in chronic mechanical back pain, and the muscle is frequently discussed in relation to segmental instability and targeted motor control retraining. The close relationship to the zygapophysial (facet) joints and the dorsal rami also makes this anatomy relevant when explaining facet-mediated pain patterns and the rationale, limitations, and potential denervation effects of medial branch radiofrequency ablation. Use this illustration for gross anatomy lab orientation of the deep back, for spine biomechanics lectures in physical therapy or sports medicine curricula, and for textbook figures contrasting superficial back muscles with transversospinalis. It also fits patient education materials on lumbar stabilization programs and postoperative rehabilitation after lumbar decompression or fusion, where multifidus inhibition and reactivation are common talking points. Anatomical accuracy verified by SciePro's Medical Advisory Board.