Multifidus Muscle
| Muscle | Origin | Insertion | Innervation | Action |
|---|---|---|---|---|
| Multifidus |
Origin
Sacrum, ilium, mamillary process of L1-L5, T1-T4 (TP and Articular process), C4-C74
Insertion
Superomedially to SP (skipping 2-4 vertebrae)4
Innervation
Action
Dysfunction
Imaging has correlated degenerative changes in the multifidus and erector spinae with increased lumbar disc herniation and facet joint osteoarthritis5.
Degenerative changes in multifidus are defined as a decreased in muscle density, cross-sectional area, and increases in fatty infiltration5.
Therex
How to recruit multifidi instead of obliques? One can bias the multifidi over the obliques by performing exercises that require spine extension rather than flexion.
Single leg bridge
One can recruit the multifidus muscle by having a patient perform a single leg bridge. In this exercise, one will have a leg on the ground (stance leg) and another leg in the air. Both shoulders will remain on the ground the whole time. As an example, we will imagine an individual using their R leg as the stance leg. Since both shoulders are stationary, the weight of the pelvis and raised leg (L) will add a load d/t gravity that pulls the L hip towards the ground, resulting in relative right rotation. Thus, in order to keep the pelvis level, one must perform active left rotation using the R multifidus since the multifidi perform C/L rotation unilaterally. An easy way to remember which multifid you are recruiting during S/L bridge is that the multifidi on the same side as the stance leg is being recruited.