The article presents the semantic-motivational analysis of Russian dialect and common words with the prefix bez- derived from words denoting somatic objects relating to the head and face zone (for example, bezglazyi “one-eyed”, bezzubyi “unsharp, weak, powerless”). Semantic types of somatic derivatives with the prefix bez- are identified. The conducted analysis helps to state that the ideas of absence of body parts relating to the head zone are highly detailed; the ideas of various somatic objects are asymmetrically “elaborated” in the language. The article reveals the words denoting functional organs that have the bigger potential of the secondary meaning development in comparison with the other lexemes of this group. The author determines the dependence of the semantic derivative's character on the named body part's functionality degree, its importance for life as well as on the stylistic and semantic peculiarities of the productive stem. The lexemes without prefixes are compared with the lexemes which inner form reflects the somatic object absence with the help of the prefix bez-. It allows raising a question on peculiarities of the corporal norm's reflection in the language.