This afternoon I decided to take care of a few unpleasant tasks that have been loitering at the top of my data collection to-do list for the past few weeks. First up was dealing with some sediment-encased crania that I needed to clean in order to hunt for the human teeth I’m using in my dental MNI. The excavators of the necropolis I’m currently working on decided to take a hands-off policy with complete crania, usually leaving them encased in blocks of hardened, dry sediment. I call this process of cleaning these crania “microexcavation”, because I effectively have to hunker down in the museum basement and use tiny tools to excavate out any scraps of bone I can see. This would be a relatively easy undertaking were it not for the fact that these chunks are essentially sedimentary cement, and often contain other human bones. So far I’ve pulled fibular ends, carpals, metatarsals, and phalanges out of some of these cranial pedestals. Depending on the state of preservation of the cranium, I soak it in water before excavating it out with a dental pick, spot clean it with a mixture of alcohol and water before using small tools to pry the drying sediment off, or dry clean it with tooth picks in the rare instance the sediment is soft enough.
Today, however, I was confronted with a particularly thorny conundrum:
As you can see, some of the dentition was still articulated in the maxilla, and soaking this entire cranium in water might lead the teeth to come loose, or worse yet, destroy the cranium itself. The solution I hit upon was to pour a small amount of water over a clearly defined area, and then excavate quickly while the sediment was still soft enough to dislodge. Because this individual was so beautifully intact, I wound up using a dental pick to excavate out the contours of the face and basicranium (and, as it turned out, some of the flesh of my left thumb, as the above photo demonstrates). Unfortunately, since the surrounding sediment was so hard, using less destructive tools like tooth picks or wooden skewers was not an option.
Though somewhat tedious, microexcavation of this nature requires an intimate knowledge of the contours of whatever element you’re excavating, or else you’re likely to damage some of the more delicate bones. A harrowing hour or two later, I’d finally managed to extract it:
As you can see, there were a number of other bones, including a scaphoid, rib head and proximal phalanx, that were encased in the block of sediment below the cranium. And while the process was time-consuming, it did allow me to learn something very important about the individual.
My challenge for you is to describe what, precisely, I was able to learn just from excavating out this cranium. I’ve added a few more photos below as a hint. The more specific you can be, the better!
Anterior view of the lower face:
Whoever guesses correctly wins ten osteology life bonus points.
Image Credits: All images were taken at the Museo de Jaén in summer 2014.