Nuances between the various words for "head" and how to write them

Question

The ways I have noted are:

1. あたま, which can only be written 頭
2. かしら, which can be written as 頭, 頁, or 首
3. こうべ, which can be written as 頭 or 首
4. かぶり, which can only be written as 頭
5. おつむ, which can be only written as 御頭
6. つむり, which can only be written as 頭 (not a kanken reading though, so is this archaic?)
7. (archaic): つぶり, which was written as 頭 (presumably the origin of つむり)
8. (archaic): かぶ, which was written as 頭, which is the origin of 株 and presumably かぶり

I know あたま is the most common, and かしら isn't rare to hear, just from my experience. I've never heard of 3 through 6 though (and 7 and 8 obviously).

What I want to know is why someone would choose any of 1 through 6 over the others. Also, what nuances are carried when writing かしら or こうべ in the other ways? They aren't jouyou readings, but I'm curious when authors would choose to use one (since they are at least kanken readings).

Edit: What I have figured out so far is that おつむ is a childish way to refer to the head, and かぶり is basically exclusively used in 頭を振る.

Answer 1

I'm not sure archaic is appropriate, but 6-8 are not in current use.

For 3-5, they appear only in fixed combinations.

• [首]{こうべ}を垂れる bow, (symbolically) be modest
• [頭]{かぶり}を振る shake one's head (to mean no); The modern equivalent is [首]{くび}をふる. コトバンク has the same usage for かしら and あたま, but I guess these two are not common in modern speech either.
• おつむ is defined as 頭。主として幼児に対して用いる。, but I guess it would be seen used as a pejorative in modern fiction (or maybe in real life by some very rude speakers). I think this is usually written in hiragana. Examples: 足りないおつむで考えろ Think with your pea-brain! ; 日本の政治家はおつむが弱い Japanese politicians are lacking intelligence.

For こうべ and かぶり, the above are pretty much the only phrases you may encounter in modern speech. For おつむ, there can be many variants, but basically it is used to mean stupid mind in combination with phrases meaning weak.

The uses of かしら which is in current use and cannot be replaced by あたま are:

• Boss: again this is not exactly current, but frequently seen in fiction. The leader of bandits may well be called かしら. I don't really think there are real groups of people whose leader is called かしら, not even Japanese mafias.
• head of fish: [尾頭]{おかしら}付き means a fish cooked with its shape intact, usually used for expensive fish (esp. 鯛). This may be considered as a set phrase.

For other cases where you mean just head, あたま should be fine (except the difference between English and Japanese on what is head and what is neck like [首]{くび}を振る above).