# sinuses **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [May 31, 2005, 9:42pm UTC](https://boards.straightdope.com/t/sinuses/306273 "2005-05-31T21:42:37Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![Adam\_Sroka](https://avatars.discourse-cdn.com/v4/letter/a/dec6dc/32.png) [@Adam\_Sroka](https://boards.straightdope.com/u/Adam_Sroka)\ **Post date:** [May 31, 2005, 9:42pm UTC](https://boards.straightdope.com/t/sinuses/306273/1 "2005-05-31T21:42:37Z")
In response to this answer: [http://www.straightdope.com/classics/a2\_302.html](http://www.straightdope.com/classics/a2_302.html) I would suggest that a more interesting theory is the aquatic ape theory. Here is a pubmed abstract of a relevant article: > **[The paranasal sinuses and other enigmas: an aquatic evolutionary theory - PubMed](https://pubmed.ncbi.nlm.nih.gov/1564378/?dopt=Abstract)** > > The functional role of the paranasal sinuses in man has long been in dispute and as yet no satisfactory explanation has been offered for these 'unwanted' spaces. An answer may be found by study of the comparative evolutionary development of the... ---
**Author:** ![John\_W.Kennedy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_w.kennedy/32/1031_2.png) [@John\_W.Kennedy](https://boards.straightdope.com/u/John_W.Kennedy)\ **Post date:** [May 31, 2005, 10:14pm UTC](https://boards.straightdope.com/t/sinuses/306273/2 "2005-05-31T22:14:35Z")
> [@Adam Sroka](#): > > In response to this answer: > [http://www.straightdope.com/classics/a2\_302.html](http://www.straightdope.com/classics/a2_302.html) > > I would suggest that a more interesting theory is the aquatic ape theory. Here is a pubmed abstract of a relevant article: > [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list\_uids=1564378&dopt=Abstract](http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1564378&dopt=Abstract) The Aquatic Ape Hypothesis is [not thought much of around here.](http://www.straightdope.com/mailbag/maquaticape.html) ---
**Author:** ![Mathochist](https://avatars.discourse-cdn.com/v4/letter/m/c89c15/32.png) [@Mathochist](https://boards.straightdope.com/u/Mathochist)\ **Post date:** [June 1, 2005, 6:52am UTC](https://boards.straightdope.com/t/sinuses/306273/3 "2005-06-01T06:52:39Z")
Has anyone advanced the theory that sinuses are, well, an accident? They don’t really help, and they don’t hurt all that much (in the grand scheme of things), so there was just never any selective pressure at all. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [June 1, 2005, 3:32pm UTC](https://boards.straightdope.com/t/sinuses/306273/4 "2005-06-01T15:32:26Z")
Of course, to the extent that they influence the shape of the face, there would be selective pressure, due to sexual selection. But sexual selection is a positive-feedback system, which means it eventually leads to essentially random traits. In other words, sinuses could have started as a neutral fluke trait, but once sexual selection got ahold of them, they were reinforced. ---
**Author:** ![C\_K\_Dexter\_Haven](https://avatars.discourse-cdn.com/v4/letter/c/b2d939/32.png) [@C\_K\_Dexter\_Haven](https://boards.straightdope.com/u/C_K_Dexter_Haven)\ **Post date:** [June 1, 2005, 9:20pm UTC](https://boards.straightdope.com/t/sinuses/306273/5 "2005-06-01T21:20:55Z")
I thought they dated back to the Cold War and the famous treaty between sinuses and the Communist Russians, calledthe Sinus-Soviet alliance… ? ---
**Author:** ![Adam\_Sroka](https://avatars.discourse-cdn.com/v4/letter/a/dec6dc/32.png) [@Adam\_Sroka](https://boards.straightdope.com/u/Adam_Sroka)\ **Post date:** [June 2, 2005, 4:33am UTC](https://boards.straightdope.com/t/sinuses/306273/6 "2005-06-02T04:33:32Z")
> [@John W. Kennedy](#): > > The Aquatic Ape Hypothesis is [not thought much of around here.](http://www.straightdope.com/mailbag/maquaticape.html) fair enough. While the theory sounded pretty hokey to me, so did most of the stuff in the original answer. If we’re grabbing at unproven theories we may as well choose some fun ones, right? Here is some more interesting stuff: [http://jap.physiology.org/cgi/content/full/85/2/405](http://jap.physiology.org/cgi/content/full/85/2/405) [http://www.dur.ac.uk/t.c.rae/CT/Rae\_Koppe\_Evol%20Anth.pdf](http://www.dur.ac.uk/t.c.rae/CT/Rae_Koppe_Evol%20Anth.pdf) ---
**Author:** ![Hostile\_Dialect](https://avatars.discourse-cdn.com/v4/letter/h/e495f1/32.png) [@Hostile\_Dialect](https://boards.straightdope.com/u/Hostile_Dialect)\ **Post date:** [June 2, 2005, 4:42am UTC](https://boards.straightdope.com/t/sinuses/306273/7 "2005-06-02T04:42:45Z")
I propose “sinai” as an alternative plural. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [June 3, 2005, 1:47am UTC](https://boards.straightdope.com/t/sinuses/306273/8 "2005-06-03T01:47:37Z")
> [@Chronos](#): > > Of course, to the extent that they influence the shape of the face, there would be selective pressure, due to sexual selection. But sexual selection is a positive-feedback system, which means it eventually leads to essentially random traits. In other words, sinuses could have started as a neutral fluke trait, but once sexual selection got ahold of them, they were reinforced. And let’s not forget that most of the physical features of _Homo sapiens_ are **neotenic** – that is, they retain their juvenille character well into adulthood. (Adult male humans don’t grow crests on their chests, for example, while all of the other adult male great apes do.) It may be that the sinuses allow the human face to retain its juvenille appearance as it grows. I guess you could call us Baby-Faced Apes. ---
**Author:** ![Foghead](https://avatars.discourse-cdn.com/v4/letter/f/76d3ee/32.png) [@Foghead](https://boards.straightdope.com/u/Foghead)\ **Post date:** [June 6, 2005, 12:09pm UTC](https://boards.straightdope.com/t/sinuses/306273/9 "2005-06-06T12:09:49Z")
> [@tracer](#): > > And let’s not forget that most of the physical features of _Homo sapiens_ are **neotenic** – that is, they retain their juvenille character well into adulthood. (Adult male humans don’t grow crests on their chests, for example, while all of the other adult male great apes do.) What is a chest crest? ---
**Author:** ![rwjefferson](https://avatars.discourse-cdn.com/v4/letter/r/a6a055/32.png) [@rwjefferson](https://boards.straightdope.com/u/rwjefferson)\ **Post date:** [June 6, 2005, 1:12pm UTC](https://boards.straightdope.com/t/sinuses/306273/10 "2005-06-06T13:12:19Z")
As man began walking upright, the Foramen Magnum (where the spinal column enters the skull) migrated from the back of, to underneath, the head. As there is no efficient way to obtain muscular support for a long and heavy face, this created the need to balance the head on the backbone. This is why homo sapiens have a flattened face, sinuses, impacted wisdom teeth and (many of us) crowded teeth. rwj ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [June 6, 2005, 11:48pm UTC](https://boards.straightdope.com/t/sinuses/306273/11 "2005-06-06T23:48:48Z")
> [@Foghead](#): > > What is a chest crest? My mistake. I meant the sagittal crest, which is on top of the head and is very pronounced in adult male gorillas.