It is also called "Mongolian fold" because it is common in ethnic groups in East and Southeast Asia, Khoisan people in South Africa and Madagascar aborigines, but it may also occur in all ethnic groups, not limited to "Mongolian race".
Extended data
Mongolian fold is usually the continuation of upper eyelid fold, and its development is obviously related to the height of nose bridge. The well-developed epicanthus folds were only found in the low nose bridge group, and the height of the nose bridge was negatively correlated with the inner Mongolia folds in group B.
A low nose bridge is not a necessary condition for Mongolian pleats to appear. People with a low nose, whether from the whole group (such as blacks) or from individuals, can have no Mongolian pleats at all.
Epicanthus can be divided into congenital and acquired. Congenital epicanthus is mostly bilateral, with genetic characteristics, and severe cases are often accompanied by ptosis, ptosis and other deformities. Acquired canthus is mostly caused by trauma, burns and other reasons, mostly unilateral, and often accompanied by adjacent tissue damage, such as lacrimal canaliculus injury, canthus ligament injury and so on.
Clinically, epicanthus can be divided into simple epicanthus and complex epicanthus. The former has only epicanthus, slightly narrow eye fissure, single eyelid or inner double, and no other deformities; The latter is accompanied by obvious narrowing of eye fissure, thickening of eyelid skin and subcutaneous tissue, dysplasia of orbicularis oculi muscle, short and narrow tarsal plate and frequent ptosis.
References:
Baidu Encyclopedia-Mongolia Folding
References:
Baidu encyclopedia-epicanthus