👉 The term "penannular" is a medical term that refers to a group of two or more smaller blood vessels called arterioles. These arterioles are located in the walls of the arteries and connect the blood vessels together, allowing for smooth flow of blood throughout the body. The term "penannular" was coined by American obstetrician Dr. William C. Penannell in 1863 to describe a group of these small blood vessels.
