The best source to answer this question is the Edwin Smith Papyrus.  This wondrous document can be credited to 3 men of the ancient past.  The first was an unknown, highly knowledgeable swnw who lived during the Old Kingdom.  The second figure appears centuries later and served as a commentator, making 69 short explanations of the earlier text.  Finally we come to the scribe who copied down these earlier texts in circa 1650 B.C.  Regrettably, for some unexplained reason, this scribe only copied half of the earlier text, so we have cases that deal with the head down to the waist and then the writing ends.