Spine, backbone, back, vertebrae, chine designate the articulated column of bones which is the central and axial feature of the skeleton of human beings and other vertebrate animals.
Spine, backbone, back, and vertebrae can be used without distinction, but one of the first three is more likely to be chosen when the structure is considered as a unit, and the last when its composite structure is pertinent.
Spine and backbone are more often used in reference to human beings than to lower vertebrates; spine is often felt as more technical than backbone and is likely to be preferred when the intent is to appear informed or knowledgeable, but spine is also appropriate when vertebrae could be misleading.
Back, more often than spine or backbone, applies to the bony column together with ligaments and muscles that support it and collectively make up a distinguishable part of the vertebrate body.
Vertebrae is likely to occur in technical anatomical use and in general use is often preferred when the reference is to other than human beings.
Chine has lost this basic meaning except indirectly in application to meat animals, in which it is applied to a cut of meat including part of the backbone.