The measuring point here must have been set out early on in the carving process and acted as a point of reference throughout. Why it was left is not clear but perhaps this panel was rushed into use.
Following the working of the surfaces with the tooth chisel the same tool was then used to define the form of the musculature to give emphasis to it. This chisel again seems to have four flat teeth.
A round-headed chisel is also used to define the lower edge of the musculature, which the carver used following along the line established by prior tooth chiselling.