脊梁 is often used figuratively to mean moral backbone or core strength. 民族的脊梁 (backbone of the nation) is a common patriotic expression.
mistakes
Both readings are in use for 脊梁. Vocabulary lists and careful speech give the full second tone, jǐliáng, while ordinary speech reduces it to jǐliang, the form stored here. It is one word either way, not two, and the meaning does not change.
