John Thomas sign

The John Thomas sign, also known as the Throckmorton sign,WhoNamedIt|synd|3050] is a joke in the medical community which involves the position of a penis as it relates to pathology on an x-ray of a pelvis.cite journal |author=Thomas MC, Lyons BD, Walker RJ |title=John Thomas sign: common distraction or useful pointer? |journal=Med. J. Aust. |volume=169 |issue=11-12 |pages=670 |year=1998 |pmid=9887926 |doi= |url=http://www.mja.com.au/public/issues/xmas98/thomas/thomas.html]

When the penis (visible on the x-ray as a shadow) points towards the same side as a unilateral medical condition (such as a broken bone), this is considered a "positive John Thomas sign", and if the shadow points to the other side, it is a negative John Thomas sign.

The sign is employed as a humorous aside. However, some analysis of its validity has been performed. [cite journal |author=Mouzopoulos GJ, Stamatakos MK, Mouzopoulos DJ |title=Does penis radiological shadow indicate the side of hip fracture? |journal=J Postgrad Med |volume=53 |issue=3 |pages=217 |year=2007 |pmid=17700004 |doi= |url=http://www.jpgmonline.com/article.asp?issn=0022-3859;year=2007;volume=53;issue=3;spage=217;epage=218;aulast=Mouzopoulos] Genital asymmetry correlates with handedness,cite journal |author=Bogaert AF |title=Genital asymmetry in men |journal=Hum. Reprod. |volume=12 |issue=1 |pages=68–72 |year=1997 |month=January |pmid=9043905 |doi= |url=http://humrep.oxfordjournals.org/cgi/pmidlookup?view=long&pmid=9043905] and a relationship between handedness and injury has been proposed as a mechanism for the sign.

References