{HEAD ~ The anchor structures} may take many forms, and may include {TAIL ~ barbed, helical, and crimp type anchors} 
include
{ HEAD ~ The anchor structures } may take many forms , and may include { TAIL ~ barbed , helical , and crimp type anchors }
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL