part of part of develops from develops from pectoral fin paired fin radial element pectoral fin endoskeletal disc radial element pectoral fin radial element Pectoral fin radial elements are the internal skeletal supports of the pectoral fin which develop from the pectoral fin endoskeletal disc, supports the pectoral lepidotrichia or fin rays and connects the lepidotrichia with the primary pectoral girdle. There are two paired series of pectoral radial elements, the proximal and the distal ones that may have variable shapes and sizes. UBERON:2101586 pectoral actinost pectoral fin radial skeleton