What condition involves blood loss from blood vessels due to medical or traumatic reasons?

The condition that involves blood loss from blood vessels due to medical or traumatic reasons is hemorrhage. This occurs when there is a rupture or damage to blood vessels, leading to the escape of blood either inside the body (internal hemorrhage) or externally (external hemorrhage). Hemorrhage can result from various factors, including injuries, surgical procedures, or underlying medical conditions that affect blood vessel integrity.

In contrast, atherosclerosis refers to the buildup of fatty deposits in the arteries, which can lead to narrowing and increased risk of blood flow issues, but does not directly denote blood loss. Edema is the accumulation of fluid in body tissues, often as a result of inflammation or injury, and does not involve blood loss. Thrombophlebitis refers to the inflammation of a vein due to a blood clot, which can cause complications but is not characterized by significant blood loss from blood vessels. Thus, hemorrhage specifically denotes the condition of blood loss, making it the correct choice.