Life, for all we know, is a thoroughly physical experience. So physical, indeed, that the body and its various parts have been the source of countless metaphorical extensions that can refer to things entirely beyond our human shell.
In English, for instance, there’s the mouth of the river, the foot of the mountain, the lid of the saucepan, the hands of the clock and, thinking about it, the clock has a face, too. Japanese similarly borrows from the domain of the body, often in overlap with English but also with entirely different ideas.
Let’s start at the top, where we find the head, or 頭 (atama). Like in other languages, this item is frequently used to signify the “da capo” part of something (note the Italian use of “head” here), such as a text (文章の頭, bunshō no atama) or a piece of music (曲の頭, kyoku no atama).