Arthroscopic (endoscopic) image of a damaged (torn) knee cartilage. An arthroscope is a type of rigid endoscope, a steel tube containing optical fibres, a lens and light source in addition to a surgical attachment (a scalpel, for example). Here, the tube would be inserted through a small incision in the knee to allow the surgeon to shave & reshape the damaged cartilage by remote manipulation. The eyepiece of the device is fitted with a video camera attachment so that the progress of the operation may be followed by students.