shoulder girdle(n = noun.body) pectoral arch - the bony arch formed by the collarbones and shoulder blades in humans;
is a kind of arch
is a part of pectoral girdle

cold shoulder, girdle, hard shoulder, keep one's shoulder to the wheel, panty girdle, pectoral girdle, pelvic girdle, picnic shoulder, shoulder, shoulder bag, shoulder blade, shoulder board, shoulder bone, shoulder flash, shoulder holster, shoulder in, shoulder joint, shoulder mark, shoulder pad, shoulder patch, shoulder strap, shoulder vise, venus's girdle