blunt force injuries

メキシコの警察がマルコムＸの孫であるマルコム・シャバズ氏の殺害容疑で男性二人を拘束しました。

Mexico arrests two over murder of Malcolm X's grandson

Police in Mexico have detained two men suspected of involvement in the murder of Malcolm Shabazz, the grandson of US political activist Malcolm X.
＜中略＞
'Blunt-force injuries'

Mr Suarez said he and Malcolm Shabazz had been invited to a bar on Wednesday night by a woman.

The bar owner later demanded they pay $1,200 (£780) for drinks and female companionship, according to Mr Suarez.

He said he had escaped as a fight broke out, before returning to find his friend seriously injured on the ground outside the bar.
http://www.bbc.co.uk/news/world-latin-america-22507782

blunt force injuriesについてですが、まずbluntを辞書で確認すると、「<刃・先端などが>（もともと）鈍い、とがっていない、丸くなった；なまくらの、切れない」とあります。（『ジーニアス英和辞典　第４版』大修館）したがってblunt force injuriesは「鈍器損傷」になります。（Weblio辞書）
The Free Dictionaryには"A traumatic injury caused by the application of mechanical force to the body by a blunt force, object or instrument—e.g., cricket or baseball bat, brick, bottle—or an injury in which the body strikes a surface such as a wall or the ground, in which the skin was not penetrated; such injuries usually result from assaults, abuse, accidents or resuscitative measures"と載っています。壁や地面にぶつかったときの外傷のことも指すようです。(Hatahata)