The right anterior horn is usually taken, with 2.5 cm next to the midline and 2 cm inside the hairline (2.5); or 2.5 cm next to the midline and 2.5 cm in front of the coronal suture as the puncture point, with a skin incision 3 cm long; parallel to the sagittal plane, aligned with the midpoint of the hypothetical line connecting the two external auditory canals; generally entering 5 cm or entering no deeper than 5 cm to prevent blockage by the choroid plexus. A silicone tube or an 8-gauge catheter is placed. Generally take the right posterior horn, 5-6 cm above the external occipital ridge as the puncture point, 3 cm next to the midline, with a skin incision 3 cm long; parallel to the sagittal plane, aligned with the plane of the ipsilateral orbital crest; generally enter 5-6 cm or enter no more than 5-6 cm deep to prevent blockage by the choroid plexus. A silicone tube or an 8-gauge catheter is placed. Indications: Removal of blood accumulation in the ventricular system, treatment and prevention of acute obstructive hydrocephalus/central hyperthermia/ventricular reaction and other serious complications due to blood accumulation in the ventricular system; also bilateral ventricular drainage and counter-oral flushing. For example, our department often performs: lateral ventricular hemorrhage casts; hemorrhage in the thalamus or basal ganglia region breaking into the lateral ventricles; cerebellar hemorrhage breaking into the fourth ventricle; brainstem hemorrhage resulting in impaired cerebrospinal fluid circulation. Precautions: When diffuse brain swelling or cerebral edema causes normal or shrunken ventricles, try not to puncture; puncture is difficult and drainage is also difficult; try not to puncture when the midline is severely deviated or reposition according to the results of head CT at that time when the midline is mildly deviated; pay attention to postural drainage and closed tube test for 24 hours; sudden transitional decompression is strictly prohibited at the initial stage, and cerebrospinal fluid should be released gradually; the cranial cone should be drilled through the dura in case the brain needle cannot be passed to cause dural traction Epidural hematoma.