Nationwide Mutual Insurance says its pet insurance business spends more money on head trauma than any other dog-park injury. Average spending on such cases is $591, according to the company. Other dog-park injuries include dog bites or other lacerations, costing an average of $361; insect bites, at $143; and heat stroke or hypothermia, which averages $579 for treatment. The most common dog-park injury among the company’s beneficiaries was soft tissue injury and sprain, with close to 24,000 such cases last year.  Bloomberg (5/18)