Let's talk a little bit about the corridor from below, which is called a transsphenoidal approach. And again, transsphenoidal because you're going through the sphenoid sinus to gain access to the pituitary tumor. That access corridor in many respects is the easiest on the patient. The incisions are usually smaller. The recovery period is usually faster. And to a large extent, these tumors are soft and in general, pituitary Adenomas are soft tumors. And so when you find yourself in the sphenoid sinus, surgeons looking into the sphenoid sinus, sees the pituitary mass sort of hanging down into the surgical field. There may be a thin layer of bone still covering it, but in large tumors, that bone is actually eroded away. And you'll be faced with a thin layer of Mucosa and the lining of the brain, which is called the Dura.