Characterization of the early development of specific hypaxial muscles from the ventrolateral myotome

Yuval Cinnamon, Nitza Kahane, Chaya Kalcheim*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

93 Scopus citations


We have previously found that the myotome is formed by a first wave of pioneer cells generated along the medial epithelial somite and a second wave emanating from the dorsomedial lip (DML), rostral and caudal edges of the dermomyotome. In this study, we have addressed the development and precise fate of the ventrolateral lip (VLL) in non-limb regions of the axis. To this end, fluorescent vital dyes were iontophoretically injected in the center of the VLL and the translocation of labeled cells was followed by confocal microscopy. VLL-derived cells colonized the ventrolateral portion of the myotome. This occurred following an early longitudinal cell translocation along the medial boundary until reaching the rostral or caudal dermomyotome lips from which fibers emerged into the myotome. Thus, the behavior of VLL cells parallels that of their DML counterparts which colonize the opposite, dorsomedial portion of the myotome. To precisely understand the way the myotome expands, we addressed the early generation of hypaxial intercostal muscles. We found that intercostal muscles were formed by VLL-derived fibers that intermingled with fibers emerging from the ventrolateral aspect of both rostral and caudal edges of the dermomyotome. Notably, hypaxial intercostal muscles also contained pioneer myofibers (first wave) showing for the first time that lateral myotome-derived muscles contain a fundamental component of fibers generated in the medial domain of the somite. In addition, we show that during myotome growth and evolution into muscle, second-wave myofibers progressively intercalate between the pioneer fibers, suggesting a constant mode of myotomal expansion in its dorsomedial to ventrolateral extent. This further suggests that specific hypaxial muscles develop following a consistent ventral expansion of a 'compound myotome' into the somatopleure.

Original languageAmerican English
Pages (from-to)4305-4315
Number of pages11
JournalJournal of Embryology and Experimental Morphology
Issue number19
StatePublished - Oct 1999


  • Avian embryo
  • Dermomyotome
  • Dorsomedial lip
  • Myf-5
  • MyoD
  • Myogenesis
  • Myogenin
  • Neural tube
  • PAX
  • Pioneer myotomal cells
  • Sclerotome
  • Somite
  • Ventrolateral lip


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