The thoracic splanchnic nerves are a group of nerves that originate from the thoracic region of the spinal cord. They are part of the autonomic nervous system and primarily carry sympathetic fibers. These nerves play a crucial role in transmitting signals to the abdominal organs, influencing functions such as digestion and blood flow. There are three main types of thoracic splanchnic nerves: the greater splanchnic nerve, the lesser splanchnic nerve, and the least splanchnic nerve. Each of these nerves innervates different abdominal organs, including the stomach, liver, and kidneys, helping to regulate their activities during stress or rest.