Microexcavation of a Prehistoric Human Cranium

CraniumThis 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:

CraniumAs 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:

Microexcavated craniumAs 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:

DSCN9636

Right lateral view:
DSCN9638
Inferior view:

Inferior View

Whoever guesses correctly wins ten osteology life bonus points.

Image Credits: All images were taken at the Museo de Jaén in summer 2014.

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This entry was posted in Bioarchaeology, Cranium, Human Teeth. Bookmark the permalink.

7 Responses to Microexcavation of a Prehistoric Human Cranium

  1. Caroline says:

    A child, perhaps? The front tooth on the left side (to our eyes) doesn’t look as though it’s fully erupted.

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    • JB says:

      Hi Caroline!

      You’re right to focus on those erupting central incisors. It’s hard to tell based on the photo, but the lateral ones aren’t erupted either yet…

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  2. James R Lumbard says:

    A child of ~5 y.o? Not very good at teeth (or eruption sequences) but I think that’s M1 erupted.

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    • JB says:

      Hi James,
      Ten osteology life bonus points to you as well as Caroline! The first molars actually haven’t quite erupted (I didn’t post a photo of the occlusal surfaces of the teeth, but what look like the M1s in the anterior and lateral views are actually the deciduous second molars). Using Ubelaker (1989) and Thoma and Goldman’s Chronology of the Human Dentition (1961) I estimated the age of this individual to be a little younger, along the lines of 2-4 years.

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      • James R Lumbard says:

        Close enough, I’ll take follow-on points for age, assuming M1 eruption 😛
        Maybe I should have tried to use your cheat sheet to identify premolars!

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      • And if we take into consideration that the metopic suture closes before 3yo(except in case of persisting as a non metric trait in older ages) then you can definitely narrow down the age between 3-4yo.

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  3. Pingback: Bone Broke Year in Review | Bone Broke

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