Talk:Human pelvis

Is the pelvis flexible?
Is the pelvis flexible? —Preceding unsigned comment added by 118.173.5.216 (talk) 08:46, 20 March 2008 (UTC)
 * Basically no. However, during pregnancy it can actually "soften-up" a bit. --Addingrefs  ( talk | contribs ) 12:13, 18 June 2009 (UTC)

Sacrum as a keystone
I'm in the process of expanding this article and just ran into a problem. In some references the sacrum is described as acting as a keystone in the "pelvic arch". Other references are stating the opposite. See quotes below.

The sacrum articulates with an auricular surface on each ilium and acts as a keystone in an arch; the shapes of the articular surfaces give the SIJs a high degree of strength and stability through a degree of form closure. In order for there to be a movement within the SIJ, the form closure is not complete and a degree of force closure is required for stability. This is provided by the erector spinae, multidius, gluteus maximus, latissimus dorsi, and biceps femoris. Compression of the SIJ occurs when the gluteus maximus and contraleteral latissmus dorsi contract. (Ebrall et al (2004), p 224)

[The sacrum] is in no sense a key-stone to an arch, because, as may be seen in antero-posterior transverse section, the sacrum is wider in front than behind, and superposed weight naturally tends to make the sacrum fall towards the pelvic cavity, and so fit less closely between the hip bones. The sacrum is in reality an oblique platform, in contact with each hip bone through its articular auricular surfaces, and in this position it is suspended by the interosseous and posterior sacro-iliac ligaments, and kept securely in place by the "grip" due to the irregularity of the opposed surfaces of the two sacro-iliac articulations. (Cunningham (1915), p 338)

Any pelvis experts around? --Addingrefs ( talk | contribs ) 12:13, 18 June 2009 (UTC)

I found a good alternative reference in the tensegrity article now used in the article. Potentially NOR, but still interesting imho. --Addingrefs ( talk | contribs ) 14:48, 18 June 2009 (UTC)

Race differences
African women tend to have smaller pelvic floor areas than European women.

I removed this section from the article as it comes with several issues. The abstract linked to only mentions "African American and European American women" and concludes "5.1% smaller total pelvic floor area." This snippet of information needs some work and a wider context to fit in the article. --Addingrefs ( talk | contribs ) 14:24, 22 June 2009 (UTC)

nice trick
female and male pelvis is the same, all difference is nonsense, which is product of american sex culture and rasism. —Preceding unsigned comment added by 84.240.9.58 (talk) 10:50, 13 June 2010 (UTC)

Image misleading
The size of the female pelvis in the image is smaller than that of the male pelvis in the image. This is misleading, since the text says otherwise. May be the images are in different scales, in which case, please change them to be on the same scale. —Preceding unsigned comment added by 122.172.42.120 (talk) 12:47, 30 September 2010 (UTC)

The drawings are correct although the text could be changed to reflect that females have a larger pelvis in relation to their stature. I'm not sure what part of the body (or specifically which other bones) it's compared to but it's a ratio to another structure. Basically, the female pelvis would be larger if the subject was the same "size" as a man (again, I'm not going to change the article myself because I don't know if "size" is height, height/weight, area, volume, etc) Zephalis (talk) 03:18, 11 August 2011 (UTC)

Birth canal and bipedality
Is there an illustration on WP of the comparison of pelvises (pelvi?) between chimpanzee, Lucy (Australopithecus afarensis) and Homo sapiens--front, side and birth canal? If not, can you get one? Bipedality changed the configuration of the pelvis so that the birth canal was reduced in diameter--just at a time when the brain was increasing in size (from monkeys to apes). This produced an evolutionary bottleneck which profoundly affected the brain development in hominins (early humans). It eventually led to greatly increased post-natal brain development.Margaret9mary (talk) 22:28, 21 March 2011 (UTC)

Pelvic inclination angle
If the pelvic inclination angle "is the single most important element of human body posture", why is there no article or section in an article about it? It is a redirect to pelvis but the only mention is the above quote which is that same in the summary of the hip article. This is in need of expansion if important, or removal if unimportant. Note that there is not mention of this in the posture article which is also in need of expansion. Zephalis (talk) 03:29, 11 August 2011 (UTC)

Cow
In the section "Pregnancy and childbirth", it says "As the end of pregnancy approaches, the ligaments of the sacroiliac joint loosen, letting the pelvis outlet widen somewhat; this is easily noticeable in the cow." I think this should be re-written. It makes it sound like "cow" refers to a body part, not a bovine. — Preceding unsigned comment added by 140.160.106.113 (talk) 05:20, 5 May 2012 (UTC)