splanchnic nerves arising from the thoracic portion of the sympathetic trunks; the upper thoracic splanchnic nerves (from T1 to T4 or 5) pass to viscera above the diaphragm (mainly heart, lungs, and esophagus) and so are cardiopulmonary splanchnic nerves; the lower thoracic splanchnic nerves form the greater, lesser, and lowest splanchnic nerves and supply viscera below the level of the diaphragm, and so are abdominopelvic splanchnic nerves.