iSurgical provides a set of about 240 anatomical drawings of the human body (more are being added all the time) for viewing and drawing upon, as well as a facility for taking photographs, which can be drawn upon as well. iSurgical lets you draw freely on top of drawings and photos, utilizing several colors and line widths. You can save your annotated images to the Photo Library and send them via email. The app currently allows a textual comment as part of the annotation.
If you're a doctor or nurse, you can use this app to demonstrate to a patient what will be done in surgery. If you're a student, use this app to assist learning basic anatomy and physiology.