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Somitic origin of the medial border of the mammalian scapula and its homology to the avian scapula blade
Author(s) -
Valasek Petr,
Theis Susanne,
Krejci Eliska,
Grim Milos,
Maina Flavio,
Shwartz Yulia,
Otto Anthony,
Huang Ruijin,
Patel Ketan
Publication year - 2010
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2009.01200.x
Subject(s) - scapula , anatomy , pectoral girdle , shoulder girdle , biology , mesoderm , lateral plate mesoderm , forelimb , genetics , embryonic stem cell , gene
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.