Final answer:
The vascular disorder characterized by thread-like, red lines or patterns on the skin caused by widened blood vessels is known as spider veins. These are different from varicose veins, hemorrhoids, and deep vein thrombosis, which are other vascular conditions with distinct characteristics.
Step-by-step explanation:
Identification of a Vascular Disorder
The vascular disorder that appears as thread-like, red lines or patterns on the skin caused by widened blood vessels is known as spider veins. They are a group of dilated veins that can be seen near the surface of the skin, especially on the legs, and resemble a spider web or tree branches. This condition is different from varicose veins, which are larger, swollen blood vessels that can also appear twisted and are often visible on the legs. Spider veins are usually cosmetic issues though they can sometimes cause discomfort. Hemorrhoids are another condition involving vascular structures, but these are specifically swollen veins in the rectal area. Deep vein thrombosis is a serious condition that occurs when a blood clot forms in a deep vein, usually in the legs, rather than a cosmetic or superficial issue.
Petechiae, on the other hand, are small red or purple spots on the skin that result from blood leaking out of damaged vessels. While they may visually resemble spider veins, petechiae are indicators of a different set of medical conditions.