The word 'spinal' is a direct derivative of the Late Latin term spinalis, which itself originates from the classical Latin noun spina, meaning "thorn" or "prickle." This semantic connection is logical, as the bony projections of the vertebrae were likened to thorns. Over time, spina evolved specifically to denote the backbone or vertebral column in anatomical contexts. The suffix -alis, a common Latin adjectival formant, was appended to create spinalis, meaning "pertaining to the spine," a form which passed into English with minimal alteration to give us the modern adjective 'spinal.'

Structure: spin (spine) + al (adjective suffix) - spin: From Latin spina (thorn, backbone). In this word, it functions as the root, carrying the core meaning of "spine." - al: A suffix of Latin origin (-alis) used to form adjectives meaning "of, relating to, or characterized by."