I felt a sharp pain in my lower back.

我感到背的下部一阵剧痛。

《柯林斯英汉双解大词典》

There are two main forms of lower back pain: acute and chronic.

下背部的疼痛发主要有两种类型：急性和慢性。

youdao

I had acupuncture in my lower back.

我在后腰上做了针灸。

《柯林斯英汉双解大词典》

Doctors placed small electrodes in his lower back.

VOA: special.2011.06.01

I just want to make mention of this in case there's ever doubt, generally parentheses do solve your problem as an arithmetic but do realize this is some lower level details we'll come back to over time.

是想告诉大家如果你对某些式子的前后运算关系不确定，就加上括号,这都是一些小细节,我们以后还是会再提到的。

哈佛公开课 - 计算机科学课程节选

So just-- and we will come back to this and flush out some of these lower level details.

那么，我们还是回到这里，略去一些,没用的细节。

哈佛公开课 - 计算机科学课程节选

Swann will fly home from the Australia tour on Wednesday because of a lower back strain.

BBC: Injured Graeme Swann to miss England ODIs in Australia

Mr Wallace was shot in the lower back and the bullet then pierced his heart.

BBC: Islington flats double shooting: Men 'killed in debt row'

Ace right-hander Roy Halladay was hampered by lower back and shoulder problems last year.

WSJ: MLB 2013: Challengers gear up to take down Giants