Figure 2.

A cross-section of the developing trunk shows the formation of somites from the mesodermal cell population. Each somite forms a sclerotome, myotome, and dermatome. The trunk mesoderm will also form the mesenchyme (connective tissue, ligaments, and osseous attachment) of the trunk, but not the head or neck. Figure 2 reinforces the mesodermal origin of the trunk. Striated muscle arises from the myotome portion of somites, while connective tissue and bone are mesenchymal in origin. The transitional neck region differs by having skeletal muscle derived from somites, while the mesenchymal component is formed from the neural crest.