Homo sapiens iliocostalis thoracis muscle iliocostalis thoracis muscle MA:0002320 EMAPA:37604 Wikipedia:Iliocostalis#Iliocostalis_thoracis musculus accessorius SCTID:244856005 iliocostalis thoracis UBERON:0001400 The iliocostalis dorsi (musculus accessorius; iliocostalis thoracis) arises by flattened tendons from the upper borders of the angles of the lower six ribs medial to the tendons of insertion of the iliocostalis lumborum; these become muscular, and are inserted into the upper borders of the angles of the upper six ribs and into the back of the transverse process of the seventh cervical vertebra. FMA:22703 iliocostalis muscle