18/05/2025
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ADDOMINALI!!!!!
Lumbar Multifidus Anatomy and Chronic Low Back Pain (CLBP)
👉 The lumbar multifidus muscle (LMM), a deep paraspinal muscle essential for spinal function, lies medial to the erector spinae, descending caudolaterally from its superior attachments [2]. It consists of five muscle bands corresponding to the lumbar vertebrae (L1–L5), each divided into superficial, intermediate, and deep regions based on attachments and morphology [1, 2, 4]. Variations in LMM morphology descriptions arise from intra-individual differences or methodological inconsistencies [3].
💪 Superficial Layer
Origin and Insertion: Superficial fibers originate from the spinous processes of L1–L5, descending to the L5–S1 mammillary processes, posterior superior iliac spine, and posterior sacrum, spanning up to five spinal segments [1, 2].
Characteristics and Function: As the longest fibers, they facilitate gross spinal movements and postural control, acting as extensors with spinal rotators and erector spinae [1].
💪 Intermediate Layer
Origin and Insertion: Intermediate fibers originate from the spinous processes of L1–L3, attaching to the mammillary processes of L4, L5, and S1, respectively. The L4 band reaches S2, while L5 lacks intermediate fibers [1, 2].
Characteristics and Function: These fibers balance stabilization and intersegmental movement, serving as dynamic stabilizers [1].
💪 Deep Layer
Origin and Insertion: Deep fibers arise from the lamina of L1–L5, descending to the mammillary process two levels below, with the L5 fascicle attaching to the sacrum. They are the deepest lumbar muscles due to absent rotator fibers [1, 2, 4].
Characteristics and Function: With a near-vertical force vector, the deep layer ensures spinal stability through intersegmental compression and fine motor control [1].
🧠 Innervation
Each LMM band is traditionally thought to receive uni-segmental innervation from the medial branch of the dorsal ramus, originating inferior to the corresponding vertebra [2, 4, 5]. However, some studies suggest polysegmental innervation, with a single medial branch innervating multiple bands [6, 7]. The LMM shares innervation with zygapophysial joints, and medial branch ablation may cause denervation [6].
❤️ Blood Supply
The LMM is supplied by the dorsal branch of the lumbar artery, branching from the abdominal aorta and coursing laterally to the posterior paravertebral muscles [8–10].
🔬 Morphological and Compositional Changes in LBP
Imaging studies demonstrate that people with LBP are more likely to present with morphological and compositional asymmetries, including muscle fatty infiltration and paraspinal muscular atrophy, especially in the multifidus muscle as compared to healthy controls [11–13]. Evidence suggests that people with chronic LBP have decreased multifidus muscle cross-sectional areas (CSA, morphology) and increased fatty infiltration (composition) at a single or multiple levels of the lumbar spine [13, 14]. In tandem with these muscular changes, a decrease in muscle strength, endurance, and activation patterns in the hip and back musculature has been observed. However, causal inferences between the multifidus morphological and functional changes or pain intensity in LBP are unclear [cause or consequence debate, 15–17].
🏋️♀️Exercise Therapy to improve LM structure
A brand-new meta-analysis by Karagiannopoulou et al. [18] and a RCT by Rosenstein et al. [19] describe the capacity of motor control, lumbar stabilization and isolated lumbar extension training (best combined) to improve lumbar multifidus (LM) muscle thickness (MT) and LM cross sectional area (CSA) with less clear effects on LM fatty infiltration in CLBP patients.
📷 Figure [11].
Diagram of lumbar multifidus muscle anatomy. (A) Posterior view of superficial multifidus fibers. (B) Posterior view of intermediate multifidus fibers. (C) Posterior view of deep multifidus fibers. (D) Lateral view of lumbar multifidus muscle fibers.
📒 References
1. Rosatelli AL, Ravichandiran K, Agur AM. Three-dimensional study of the musculotendinous architecture of lumbar multifidus and its functional implications. Clin Anat. 2008;21(6):539-546. doi:10.1002/ca.20659
2. Kalimo H, Rantanen J, Viljanen T, Einola S. Lumbar muscles: structure and function. Ann Med. 1989;21(5):353-359. doi:10.3109/07853898909149220
3. Hofste A, Soer R, Hermens HJ, et al. Inconsistent descriptions of lumbar multifidus morphology: a scoping review. BMC Musculoskelet Disord. 2020;21(1):312. doi:10.1186/s12891-020-03347-6
4. Macintosh JE, Bogduk N. The biomechanics of the lumbar multifidus. Clin Biomech (Bristol, Avon). 1986;1(4):205-213.
5. Bogduk N. The innervation of the lumbar spine. Spine. 1983;8(3):286-292.
6. Wu PB, Date ES, Kingery WS. The lumbar multifidus muscle is polysegmentally innervated. Electromyogr Clin Neurophysiol. 2000;40(1):35-44.
7. Amonoo-Kuofi HS. The density of muscle spindles in the medial, intermediate and lateral columns of human intrinsic postvertebral muscles. J Anat. 1983;136(Pt 3):509-519.
8. Ratcliffe JF. The arterial anatomy of the adult human lumbar vertebral body: a microarteriographic study. J Anat. 1980;131(Pt 1):57-79.
9. Crock HV, Yoshizawa H. The blood supply of the vertebral column and spinal cord in man. J Bone Joint Surg Br. 1977;59(4):395-404.
10. Boswell MV, Singh V, Staats PS, Hirsch JA. Accuracy of precision diagnostic blocks in the diagnosis of chronic spinal pain of facet or zygapophysial joint origin. Pain Physician. 2003;6(4):449-456.
11. Abd-Elsayed A, Kurt E, Kollenburg L, Hasoon J, Wahezi SE, Storlie NR. Lumbar Multifidus Dysfunction and Chronic Low Back Pain: Overview, Therapies, and an Update on the Evidence. Pain Pract. 2025 Jun;25(5):e70044. doi: 10.1111/papr.70044. PMID: 40361257.
12. Kjaer P, Bendix T, Sorensen JS, Korsholm L, Leboeuf-Yde C. Are MRI-defined fat infiltrations in the multifidus muscles associated with low back pain? BMC Med. 2007;5:2. doi:10.1186/1741-7015-5-2
13. Goubert D, Oosterwijck JV, Meeus M, Danneels L. Structural changes of lumbar muscles in non-specific low back pain: a systematic review. Pain Physician. 2016;19(7):E985-E1000.
14. Seyedhoseinpoor T, Taghipour M, Dadgoo M, et al. Alteration of lumbar muscle morphology and composition in relation to low back pain: a systematic review and meta-analysis. Spine J. 2022;22(4):660-676. doi:10.1016/j.spinee.2021.10.018
15. Suri P, Fry AL, Gellhorn AC. Do Muscle Characteristics on Lumbar Spine Magnetic Resonance Imaging or Computed Tomography Predict Future Low Back Pain, Physical Function, or Performance? A Systematic Review. PM R. 2015 Dec;7(12):1269-1281. doi: 10.1016/j.pmrj.2015.04.016. Epub 2015 May 5. PMID: 25952771.
16. Hodges PW, Danneels L. Changes in structure and function of the back muscles in low back pain: different time points, observations, and mechanisms. J Orthop Sports Phys Ther. 2019;49(6):464-476. doi:10.2519/jospt.2019.8827
17. Ranger TA, Cicuttini FM, Jensen TS, Peiris WL, Hussain SM, Fairley J, Urquhart DM. Are the size and composition of the paraspinal muscles associated with low back pain? A systematic review. Spine J. 2017 Nov;17(11):1729-1748. doi: 10.1016/j.spinee.2017.07.002. Epub 2017 Jul 26. PMID: 28756299.
18. Karagiannopoulou V, Meirezonne H, De Greef I, Van Oosterwijck J, Matheve T, Danneels L, Willems TM. The effects of exercise therapy on lumbar muscle structure in low back pain: A systematic review and meta-analysis. Ann Phys Rehabil Med. 2025 Apr 30;68(5):101988. doi: 10.1016/j.rehab.2025.101988. Epub ahead of print. PMID: 40311262.
19. Rosenstein B, Rye M, Roussac A, Naghdi N, Macedo LG, Elliott J, DeMont R, Weber MH, Pepin V, Dover G, Fortin M. Comparison of Combined Motor Control Training and Isolated Extensor Strengthening Versus General Exercise on Lumbar Paraspinal Muscle Health and Associations With Patient-Reported Outcome Measures in Chronic Low Back Pain Patients: A Randomized Controlled Trial. Global Spine J. 2025 Mar 11:21925682251324490. doi: 10.1177/21925682251324490. Epub ahead of print. PMID: 40066720; PMCID: PMC11897994.
