Vacuolant saddle is a disease in which the subarachnoid space is protruding into the saddle under the impact of the pressure of cerebral fluid, resulting in the enlargement of the saddle and possible compression of the pituitary gland, which generally does not require treatment. It has a complex cause, which can be a congenital defect of the saddle diaphragm or pituitary atrophy, or the treatment effect of surgery or radiotherapy. According to the etiology, it is divided into primary vacuolated saddle and secondary vacuolated saddle. Secondary vacuolated saddle has a clear history of intra-saddle or para-saddle surgery and radiotherapy, while primary vacuolated saddle generally has no obvious etiology and no surgery or radiotherapy. It may be related to congenital hypoplasia of the saddle diaphragm or arachnoid adhesions in the saddle area, and some endocrine factors, such as physiological hypertrophy of the pituitary gland during pregnancy, especially in multiple pregnancies, the pituitary gland continues to increase in size, and after delivery, the pituitary gland gradually retracts, leaving a large space for the saddle diaphragm hole and pituitary fossa, which is powerful to embed the subarachnoid space into the saddle. Therefore, the primary vacuolation of the saddle occurs more often in middle-aged women with multiple pregnancies, which may be related to this. In addition, pituitary lesions may also lead to vacuolation saddle, such as spontaneous degeneration and necrosis of pituitary tumor, which can lead to saddle diaphragm adhesion, and cause the subarachnoid space to protrude into the saddle, when the pituitary function is not affected, there are no obvious symptoms, headache is a common symptom, but lack of specificity.