The shape of the ear is hereditary, the big ear is dominant compared with the small ear, and the small ear is recessive. As long as one parent has big ears, then the child is likely to have a pair of big ears.
The most common ear deformities are the outer ear and the middle ear, while the inner ear is rare. External ear malformation is mainly manifested in the abnormal position, size and shape of auricle, accompanied by different degrees of external auditory canal malformation.
There are also many factors that cause congenital ear malformation, mainly including:
(1) Genetic factors: sores caused by gene mutation or chromosome aberration, which affect individuals, including monogenic genetic diseases, polygenic genetic diseases and chromosome diseases. Such as some sensorineural deafness, atresia of external auditory canal, auricle deformity and so on.
(2) Physical factors: There are many physical factors harmful to human body in the surrounding environment, including ionizing radiation, such as α, β, γ and χ rays. ; Non-ionizing radiation, such as red light, ultraviolet light, microwave, television, etc. ; Other factors include high temperature, noise and vibration. Among them, radiation is the most harmful to human embryos, which can lead to fetal growth retardation, death and various congenital malformations.
(3) Chemical factors: Many chemicals may cause congenital malformation, including drugs, such as antibiotics, hormones, anti-tumor drugs, anesthetics, etc. Industrial products, such as heavy metals and chemical solvents; Various pesticides, fertilizers, etc. Life chemicals, such as food additives and cosmetics.
(4) Biological factors: such as rubella virus, herpes virus, Treponema pallidum, HIV, etc. , mainly through the placenta or birth canal of pregnant women directly infected with embryos or fetuses.
(5) Maternal factors: such as malnutrition of pregnant women, deficiency of various vitamins or trace elements, and sugar fart.