Naive Young Girl to Doctor

A naive young girl goes into the doctor's office. She says, "Doc, I'm getting married and I'm a little inexperienced, so I'd like to ask you a few questions." He says, "All right." She says, "All right... what is that thing that hangs between my fiancé's legs?" The doctor says, "That's the penis. The male organ, the penis." She says, "Okay. And what is that big red knob at the end?" The doctor says, "That's the glans. The head of the penis, the glans." She says, "Okay. And what are those two round things, about twelve inches behind the head?" The doctor says, "Well, lady, I don't know about your fiancé, but on me, they're the cheeks of my ass."

Mineral Shortage

Doctor: Sorry sir, but your body has run out of magnesium.
Me: 0mg 

Med Student

While making his rounds, a doctor points out an x-ray to a group of medical students. “As you can see,” he says, “the patient limps because his left fibula and tibia are radically arched.” The doctor turns to one of the students and asks, “What would you do in a case like this?”
“Well,” ponders the student, “I suppose I’d limp, too.”