In this incredible model, we get an appreciation for the complex circulatory system of a human arm. This particular model shows the arterial system in a right upper limb.

The human circulatory system carries blood around an extensive network of vessels, totalling 100,000 km (62,000 miles) in length, which is equivalent to a journey 2.5 times around Earth!

For those curious, the model was made using Vascular corrosion casting, which uses resin to capture the 3D structure of blood vessels within human and animal tissue. It is widely used in research as a technique for obtaining the volume and surface area of the blood vessel network within an organ. The earliest known use of corrosion casting was by Robert Boyle in 1663. [source]

 

Vascular corrosion casting requires the use of a solidifying material such as a resin. The most common resin used for vascular corrosion casting is Batson’s 17. The process begins with the draining of blood from vessels to prevent blockage from clotting, this can be achieved by perfusing blood vessels with a physiological fluid such as phosphate buffered saline. Subsequently, the blood vessels of interest are filled with resin (or alternative solidifying material). The resin is allowed to cure resulting in the blood vessel network containing a solid plastic material. Surrounding tissue is dissolved away using a corrosive chemical, commonly potassium hydroxide. Corrosion should not affect the resin, only dissolving tissue. The final product is a 3D network of blood vessels. [source]