The Clumsy Archer

An Olympic level archer is practicing in his yard that backs up to wooded area when he notices a white-tailed deer in a clearing. He decides to give chase and begins to move stealthily towards the woods. The deer jumps away and the archer increases his pace to track the deer until eventually he spots the deer and three fawns in a clearing. The archer slowly raises his bow and arrow taking aim to shoot when a wild turkey rushes at him from a nearby bush. The startled archer begins to fall backwards but miraculously recovers and is able to turn himself around to fall on his outstretched hand. Unfortunately, he also falls on his arrow which pierces his chest just above the sixth rib to the left of the sternum. The archer feels a sharp pain but is able to pull out the head of the arrow without difficulty. He gathers his quiver and walks back to his house, while noticing a bulge growing on his wrist accompanied by extreme pain. He reaches his home and tells his roommate that he feels faint right before collapsing. The archer is rushed to the emergency room where the chest wound is deemed minor, given that the arrow did not penetrate the chest wall. But a bulge in his hand is now quite large. Blood pressure has dropped and pulse is close to 140.  What is the likely source of the large bulge in the archer’s hand?