Despite the significance of neck muscles in musculoskeletal disorders, their microscopic anatomy remains poorly characterized. This study examined the splenius capitis muscle, focusing on its fiber-type composition, fiber size, and capillary network characteristics. For comparison and validation, the vastus lateralis muscle was also analyzed. Muscle samples from 13 young male subjects (mean age ± SD: 35.7 ± 8.6 years) were collected within 24-h post-mortem during autopsy. Myosin heavy chain (MyHC) isoform expression was characterized immunohistochemically in 10 μm sections, while the capillary network architecture was assessed in 100 μm sections. Immunofluorescence staining, confocal microscopy, and 3D image analysis were employed to quantify capillary tortuosity, anisotropy, branch density (Br dens), and the length of capillaries per muscle volume (LV), per muscle fiber length (LL), per fiber surface area (LS), and per fiber volume (LVf). Compared to the vastus lateralis muscle, the splenius capitis muscle had a higher percentage of type 1 fibers (51.2% vs 39.7%), fewer type 2a fibers (16.2% vs 31.4%), and smaller fiber diameters (35.5-40.9 μm vs 47-56.1 μm). It also displayed lower Br dens (P = 0.0069), higher anisotropy (P = 0.0004), and lower LL (P < 0.0001) but higher LVf (P = 0.0486). In the splenius capitis muscle, body mass index (BMI) negatively correlated with LV (P = 0.0155), LS (P = 0.0091), LVf (P = 0.0137), and anisotropy (P = 0.0425), and positively correlated with tortuosity (P = 0.0473), indicating a reduction in the capillary network. In the vastus lateralis muscle, only LV (P = 0.0161) decreased with high BMI. This study characterized the fiber-type composition, fiber size, and 3D capillary network of the splenius capitis muscle, establishing a baseline for investigations into pathological muscle alterations.

• MeSH
• Adult MeSH
• Capillaries * metabolism   MeSH
• Muscle Fibers, Skeletal * metabolism   MeSH
• Neck Muscles * blood supply   metabolism   MeSH
• Humans MeSH
• Myosin Heavy Chains metabolism   MeSH
• Imaging, Three-Dimensional MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Male MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Myosin Heavy Chains MeSH

Myofascial pain syndrome (MPS) is a common musculoskeletal disorder that significantly affects quality of life. Conventional treatment approaches include pharmacological interventions, physical therapy, and procedures such as dry needling. Among these, ultrasound-guided injections (USGIs) have gained recognition for their precision and therapeutic benefits. Additionally, repetitive peripheral magnetic stimulation (rPMS) has emerged as a non-invasive neuromodulatory technique for pain management. This perspective article examines the physiological mechanisms and clinical applications of USGIs and rPMS, particularly in the lumbar multifidus muscle, and explores their potential synergistic effects. MPS is often associated with chronic muscle dysfunction due to energy depletion, leading to persistent pain and motor impairment. USGIs play a crucial role in restoring muscle perfusion, disrupting pain cycles, and providing diagnostic insights in real time. In parallel, rPMS modulates neuromuscular activation, enhances endogenous pain control, and promotes functional recovery. Ultrasound guidance enhances the precision and effectiveness of interventions, such as dry needling, interfascial plane blocks, and fascial hydrodissection, while rPMS complements these strategies by facilitating neuromuscular reconditioning and reducing pain via central and peripheral mechanisms. The preliminary findings suggest that combining multifidus USGIs with rPMS results in significant pain relief and functional improvements in patients with chronic low back pain. Integrating USGIs with rPMS represents a promising multimodal strategy for managing MPS. By combining targeted injections with non-invasive neuromodulation, clinicians may optimize therapeutic outcomes and provide sustained relief for patients with chronic musculoskeletal pain. Further research is needed to refine treatment protocols and assess the long-term efficacy.

• Keywords
• intervention, multifidus, muscle, painful, ultrasonography,
• Publication type
• Journal Article MeSH