School of Biological Sciences, University of Reading, Reading, UK.
J Anat. 2010 Apr;216(4):482-8. doi: 10.1111/j.1469-7580.2009.01200.x. Epub 2010 Jan 28.
The scapula is the main skeletal element of the pectoral girdle allowing muscular fixation of the forelimb to the axial skeleton. The vertebrate limb skeleton has traditionally been considered to develop from the lateral plate mesoderm, whereas the musculature originates from the axial somites. However, in birds, the scapular blade has been shown to develop from the somites. We investigated whether a somitic contribution was also present in the mammalian scapula. Using genetic lineage-tracing techniques, we show that the medial border of the mammalian scapula develops from somitic cells. The medial scapula border serves as the attachment site of girdle muscles (serratus anterior, rhomboidei and levator scapulae). We show that the development of these muscles is independent of the mechanism that controls the formation of all other limb muscles. We suggest that these muscles be specifically referred to as medial girdle muscles. Our results establish the avian scapular blade and medial border of the mammalian scapula as homologous structures as they share the same developmental origin.
肩胛骨是胸带的主要骨骼元素，允许前肢的肌肉固定在轴骨骼上。传统上认为脊椎动物肢体骨骼是从侧板中胚层发育而来的，而肌肉则起源于轴性体节。然而，在鸟类中，已经表明肩胛骨的叶片是从体节发育而来的。我们研究了哺乳动物的肩胛骨是否也存在体节的贡献。使用遗传谱系追踪技术，我们表明哺乳动物肩胛骨的内侧边界是由体节细胞发育而来的。肩胛骨的内侧边界是肩带肌肉（前锯肌、菱形肌和肩胛提肌）的附着点。我们表明，这些肌肉的发育与控制所有其他肢体肌肉形成的机制是独立的。我们建议将这些肌肉专门称为内侧肩带肌肉。我们的结果确立了鸟类的肩胛骨叶片和哺乳动物肩胛骨的内侧边界作为同源结构，因为它们具有相同的发育起源。
