Meningioma of the lateral 1/3 of the pterygoid crest. The lateral type of pterygoid crest meningioma presents late, with tumors occurring on the large wing of the pterygoid bone, causing bone growth in the posterior lateral wall of the orbit and temporal area, and orbital shrinkage, or direct invasion of the tumor into the orbit resulting in proptosis of the eye. How is orbital shrinkage diagnosed? The clinical presentation of pterygoid crest meningioma depends on the location of the tumor. In the medial type, early symptoms are obvious, and patients may show brain nerve compression, such as vision loss, at early stage. If the tumor invades into the orbit or supraorbital fissure, the patient may have symptoms such as protrusion of the eyeball if the ocular venous return is obstructed. Patients with medial type may also have symptoms of II, IV, VI and V branch 1 brain nerve damage. Psychiatric symptoms and olfactory disturbance are mostly seen in patients with tumor growth in the anterior cranial fossa, but are less common. Lateral pterygoid crest meningioma presents late, with early headache and lack of localization signs. Some patients may present with temporal lobe seizures and zygomatic-temporal bone bulge if the tumor invades the temporal bone. When the tumor grows larger in both types of patients, it will cause muscle weakness of the contralateral limb and increase of intracranial pressure. Based on clinical manifestations, combined with CT and MRI, clinical diagnosis can be made clearly. Surgical resection of lateral pterygoid crest meningioma is not difficult, and postoperative recurrence and neurological impairment are rare. Medial meningiomas are more difficult to excise completely, and postoperative neurological impairment of III, IV, and VI brains may occur. Other patients may have postoperative limb movement disorders and motor aphasia. For patients with medial meningioma that cannot be completely resected, postoperative radiotherapy can be used to prevent recurrence. If the tumor recurs, re-surgical resection can be considered.