Here’s something a bit different from my usual Mystery Dissection images: a Mystery CT Slice with an indicated structure for you to identify. I can definitely do this quite regularly. And I’ll try to always draw the arrow on using MS Paint, quite shakily to indicate my frenetic mental state. Bonus points for identifying the organism. It’s not super hard but let’s see how you do with this one. Go for it!
EDIT: OK, you’ve had a good go at it, definitely. Almost everyone was more or less right in some way, so here, have a treat! We’re looking at a cross section of a ~6 month old emu (Dromaius novaehollandiae) from the RVC Structure and Motion Lab’s aviary. And indeed the structure is the ventriculus; the technical term for the gizzard; the muscular organ that acts like teeth for birds, grinding up food. The proventriculus is the more enzyme-producing, non-grinding compartment connected to the ventriculus. This emu had just eaten a bit of grit (the bright spots in the scan) whereas its comrade had eaten relatively huge pebbles, which surprised me when I scanned it and certainly was not accidental ingestion. Here are some labels to help orient you in this cross-sectional x-ray CT image; we’re in the cranial (anterior) region of the thorax, just a bit behind the heart and in front of the guts:
For the less anatomically-jargon-loving, the synsacrum is the hip region (fused pelvis, backbone in birds), the femur is the thigh bone, tibia and fibula are shank bones, and the tarsometatarsus is an elongate “sole bone” of the foot; actually 3 fused metatarsals and tarsal bones integrated into one unit in birds as a likely strength:weight maximizing adaptation. The air sacs of course are outpockets of the lungs, much famed among dinosaur workers of late. Of course, Dr. Oliver Wings of the Humboldt Museum in Germany is the reigning authority on dinosaur gizzards, gastric mills and the lack thereof in many dinosaurs (most notably sauropods), so look his stuff up if you’re interested in this!
Well done and thanks for playing! Another session will come soon enough, plus I have some big posts planned for later this summer once work calms down!