Symbolic trepanations of skulls from the Middle Ages (IXth-Xth century) in Bulgaria.

Symbolic trepanations (ST) of skulls (IXth-Xth century) found in north-eastern Bulgaria near the West coast of the Black Sea were Studied. It was established that trepanations were performed on subjects well over the age of thirty and cover 41% from the total material which is the highest frequency documented so far. Tracks of the ST are localized most often on and round the sagittal suture, bregma and lambda. Their number ranges from 1 to 9 per cranium with a diameter of 3-4 to 20-28 mm and a depth of 1 to 6 mm. They are usually round and encircled with a prominent ridge. In this article we try to explain the reasons for the symbolic trepanations as well as the link between the traditions of the ancient Turkish nations and Chinese medicine.