The degree of opening of the splenic blood sinus varies in children, as does the severity. Generally, mild opening can be observed dynamically, while it is more serious if it is large and accompanied by other serious complications. Blood sinusoids are capillary disorders found mainly in the liver, spleen, bone marrow and endocrine glands. Open splenic blood sinus is a capillary disease that is mainly due to the poor development of the body cavities, when the microvascular and venous cavities in the body become enlarged, forming an irregular gap. Children cause this mostly because of traumatic impact. Children are mischievous and tend to fall or bump into objects when running around, which may lead to compression of the spleen in the abdominal cavity, thus opening the splenic blood sinus. A mild opening can be observed dynamically, but a large opening with other serious complications is more serious. Parents should take their children to the doctor and follow the doctor’s advice if they notice an open spleen sinus, so don’t worry too much.