Have you ever wanted to see what the inside of your arm actually looks like? This is it — layer by layer. Beneath the skin lies a precisely organized system of fascia, muscle bellies, tendons, nerves, and vasculature — all working in perfect coordination every time you grip, lift, rotate, or throw. The forearm alone contains over 20 muscles divided into flexor and extensor compartments, all controlled by branches of the median, ulnar, and radial nerves. Most people never think about what's happe