Testicles are unique in that they hang outside of the body, inside of the scrotum. This makes the testicles particularly vulnerable to impact during activity. Trauma to the testes can cause severe pain, along with swelling and bruising. Fortunately the testicles are made of spongy material that allows them to absorb the shock of an injury without serious damage. However, in some cases, serious damage can occur.
A rare type of testicular trauma, called testicular rupture, occurs when the testicle receives a direct blow or is squeezed against the hard surface of the pelvis. This injury can cause blood to leak into the scrotum. In severe cases, surgery to save the testicle by repairing the rupture may be necessary.