Pollak Nataša, Ugwoke Chiedozie Kenneth, Umek Nejc, Alibegović Armin, Janáček Jiří, Radochová Barbora, Cvetko Erika
Institute of Anatomy, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
Institute of Forensic Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia.
Biomol Biomed. 2025 Apr 26;25(6):1351-1361. doi: 10.17305/bb.2024.10787.
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.
尽管颈部肌肉在肌肉骨骼疾病中具有重要意义，但其微观解剖结构仍未得到充分描述。本研究对头夹肌进行了检查，重点关注其纤维类型组成、纤维大小和毛细血管网络特征。为了进行比较和验证，还对股外侧肌进行了分析。在尸检过程中，于死后24小时内采集了13名年轻男性受试者（平均年龄±标准差：35.7±8.6岁）的肌肉样本。在10μm切片上通过免疫组织化学方法对肌球蛋白重链（MyHC）异构体表达进行了表征，而在100μm切片上评估了毛细血管网络结构。采用免疫荧光染色、共聚焦显微镜和三维图像分析来量化毛细血管的曲折度、各向异性、分支密度（Br dens）以及每肌肉体积（LV）、每肌肉纤维长度（LL）、每纤维表面积（LS）和每纤维体积（LVf）的毛细血管长度。与股外侧肌相比，头夹肌中Ⅰ型纤维的百分比更高（51.2%对39.7%），Ⅱa型纤维更少（16.2%对31.4%），纤维直径更小（35.5 - 40.9μm对47 - 56.1μm）。它还表现出更低的Br dens（P = 0.0069）、更高的各向异性（P = 0.0004）和更低的LL（P < 0.0001），但LVf更高（P = 0.0486）。在头夹肌中，体重指数（BMI）与LV（P = 0.0155）、LS（P = 0.0091）、LVf（P = 0.0137）和各向异性（P = 0.0425）呈负相关，与曲折度呈正相关（P = 0.0473），表明毛细血管网络减少。在股外侧肌中，只有LV（P = 0.0161）随着高BMI而降低。本研究对头夹肌的纤维类型组成、纤维大小和三维毛细血管网络进行了表征，为病理性肌肉改变的研究建立了基线。
