Mark and Scott discuss the back, spine and shoulders in terms of movement expression. They talk about the phylogeny of muscles and give details on the tonic and phasic system interplay. From the trunk they journey down to the feet
[audio:http://www.abc3116.sg-host.com/wp-content/uploads/2011/12/06-Causes-and-conditions-of-development.-Phylogeny-and-phasic-development.mp3|titles=06 Causes and conditions of development. Phylogeny and phasic development]