<Tr> <Td_colspan="2"> (edit on Wikidata) </Td> </Tr> <P> A spider angioma (also known as a nevus araneus, spider nevus, vascular spider, and spider telangiectasia) is a type of telangiectasis (swollen blood vessels) found slightly beneath the skin surface, often containing a central red spot and reddish extensions which radiate outwards like a spider's web . They are common and may be benign, presenting in around 10--15% of healthy adults and young children . However, having more than three spider angiomas is likely to be abnormal and may be a sign of liver disease . It also suggests the probability of esophageal varices . </P> <P> Spider angiomas are found only in the distribution of the superior vena cava, and are thus commonly found on the face, neck, upper part of the trunk, and arms . They may also be present on the backs of the hands and fingers in young children . </P> <P> Spider angiomas form due to failure of the sphincteric muscle surrounding a cutaneous arteriole . The central red dot is the dilated arteriole and the red "spider legs" are small veins carrying away the freely flowing blood . If momentary pressure is applied, it is possible to see the emptied veins refilling from the centre . No other angiomas show this phenomenon . </P>

Why spider naevi are in the upper half of body