Image Credit: NASA. Asked by Jon Gray. An impact basin known as Valhalla is Callistoâs largest crater with a diameter of over 300 kilometres (190 miles), while concentric rings that surround it extend out to 3,000 kilometres (1,900 miles) â nearly large enough for the entire USA to fit within its boundaries.
Somewhat surprisingly, the second most common cause of tinnitus is head and neck injuries. In a clinical study of 2,400 tinnitus patients at the Oregon Health Science University, more than 12% reported that their tinnitus had been caused by head or neck injury. (1) There are two broad categories of head and neck injury, Traumatic Brain Injury (TBI) and whiplash.
Pulsatile tinnitus also may be caused by brain tumors or abnormalities in brain structure. Even with all of these associated conditions and causes, some people develop tinnitus for no obvious reason. Most of the time, tinnitus isnât a sign of a serious health problem, although if itâs loud or doesnât go away, it can cause fatigue, depression, anxiety, and problems with memory and concentration.