What is a vascular spasm?

According to the New York Times, a vascular spasm is when the muscle cells within the walls of a blood vessel briefly tighten. Vascular spasms occur when the blood flow is blocked by a blood vessel that has significantly decreased in size or completely closed up.

The New York Times says that vascular spasms are caused by the effects of tobacco, cocaine usage, or by blood vessel irritation experienced due to internal or external causes. The symptoms of vascular spasms vary depending on which area of the body is experiencing the lack of blood flow. Although, pain is the most common symptom vascular spasms cause.