▁this ▁mus cle ▁may ▁represent ▁a ▁failure ▁of ▁proxim al ▁migration ▁of ▁u ln oc arp al ▁elements ▁of ▁the ▁ext ensor ▁mus cle ▁mass ▁in ▁humans . ▁ ▁Function s ▁ ▁It ▁extends ▁the ▁index ▁or ▁the ▁middle ▁finger . ▁It ▁is ▁believed ▁to ▁be ▁a ▁substitute ▁for ▁the ▁extension ▁of ▁the ▁index ▁finger ▁when ▁the ▁ext ensor ▁indic is ▁propri us ▁is ▁absent . ▁ ▁C lin ical ▁significance ▁ ▁Only ▁a ▁few ▁clin ical ▁cases ▁have ▁been ▁reported ▁among ▁more ▁than ▁ 3 0 0 ▁clin ical ▁and ▁cada ver ic ▁dis sections . ▁This ▁implies ▁that ▁the ▁presence ▁of ▁this ▁mus cle ▁is ▁usually ▁asympt om atic , ▁although ▁the ▁ext ensor ▁dig itor um ▁bre vis ▁manus ▁might ▁cause ▁a ▁pain ful ▁sw elling ▁which ▁can ▁potentially ▁be ▁mis di agn osed ▁as ▁other ▁path ology ▁such ▁as ▁syn ov ial ▁c yst ▁and ▁lip oma . ▁ ▁See ▁also ▁▁ ▁Ext ensor ▁indic is ▁propri us ▁mus cle ▁ ▁Ext ensor ▁med ii ▁propri us ▁mus cle ▁ ▁Ext ensor ▁indic is ▁et ▁med ii ▁commun is ▁mus cle ▁ ▁List ▁of ▁an atom ical ▁variations ▁ ▁References ▁ ▁Category : Hand ▁Category : Access ory ▁mus cle ▁Category : Mus cles ▁of ▁the ▁upper ▁lim b ▁Category : An atom ical ▁variations <0x0A> </s> ▁A cal ole pta ▁fra ud at rix ▁is ▁a ▁species ▁of ▁be et le ▁in ▁the ▁family ▁Cer amb yc idae . ▁It ▁was ▁described ▁by ▁Henry ▁Walter ▁B ates ▁in