The butterfly bone is the name of one of the bones in the skull that makes up the cranium, because its shape resembles a butterfly with its wings spread. In layman’s terms, its location is in the middle of the line connecting the temples. In detail, it is located between the frontal bone and the sieve bone, and the temporal bone and the occipital bone, and is divided into four parts: the body of the butterfly, the large wing of the butterfly, the small wing of the butterfly, and the pterygoid process. The body of the pterygoid bone has a saddle-shaped shape in the center, called the pterygoid saddle, and the pituitary gland is located inside, where lesions such as pituitary tumors and pituitary cysts are likely to occur. The supraorbital fissure and infraorbital fissure are composed of the small and large wings of the pterygoid bone, which are parallel to each other, with some tissue structures such as nerves and arteries running between them. The pterygoid bone is a relatively hollow bone and is relatively fragile, so in many cases the injury is mainly to the pterygoid bone, for example, visual impairment after trauma, which is mostly caused by damage to the optic nerve canal and compression of the vision; or epidural hematoma, which is mostly caused by the fracture line passing through and damaging the bone of the middle meningeal artery surface.