These simulations can not only be used to measure the lengths in experimental data, but can also constrain osteological ROM measurements to receive more functionally informative ROM estimates. Importantly, they are applicable to all type of joints and even fossils! 10/11

We calculated ligaments across the whole XROMM dataset and compared them to lengths measuared through dissection. It appears that different ligaments have different amounts of elasticity. Potential differences in (primary?) functions? 9/11

Similar to the osteological ROM simulation we used a signed distance field representation of the bones to speed up the optimisation process. The minimal length of each ligament was calculated from origin to insertion without any way points intersecting the bones 8/11

We were not only interested in the osteological range of motion (ROM) but also in the soft tissues constraints surrounding the joint. We simulated the ligaments of the shoulder capsule that prevent excessive movement while enabling contact between the bones during motion 7/11

Our approach is similar to work by Lee et al. (doi.org/10.1098/rspb...) but implemented in Autodesk Maya with Python. The optimisation approach minimises a cost function that determines joint proximity (cartilage thickness) and congruency (overlap) over a signed distance field 6/11

This made simulations more complicated, as previous pipelines often assumed a static joint centre around which the distal element (e.g., humerus) moves. However our approach automatically optimises joint translations for each rotational joint orientation and it is very fast! 5/11

In the shoulder we captured both joint rotations and translations. Our results clearly show that there is no (functional) joint centre in the bird shoulder and the humerus moves dynamically over the glenoid articular cartilage. The joint does not act as a spherical joint 4/11

We captured the joint motion of Red legged partridge specimens using XROMM (X-Ray reconstruction of moving morphology) and wiggled three specimens in the biplanar X-ray to capture their joint mobility 3/11

How do joints move? The articular surfaces between the proximal and distal bones are in contact during motion. However, they are usually not neatly spherical or hinge like but move in complex patterns that include sliding and/or rolling (e.g., in the shoulder joint of birds) 2/11

Last week our in press manuscript was made available at @jexpbiol.bsky.social with the typeset version following soon. We conducted ex vivo XROMM experiments to determine the joint mobility in Red legged partridges and compared them with in silico simulations: doi.org/10.1242/jeb....

Very proud of the amazing Dr. Ashleigh Wiseman! Securing an @erc.europa.eu starting grant is a huge achievement! Keep your eyes open for PostDoc opportunities in her new research group at @cam-archaeology.bsky.social @cam.ac.uk!!

I finally managed to sucessfully implement batch processing of several Maya files (parallelised onto multiple CPU cores)! Finishing the reanalyses for one of my yet to be published PhD chapters is getting closer and closer!

When did our ancestors start to run? New musculoskeletal simulations of Lucy indicate that she was capable of running!
Read the dispatch by Ashleigh Wiseman out in @currentbiology.bsky.social today: doi.org/10.1016/j.cu... and the paper by Bates et al. here: doi.org/10.1016/j.cu...

Quick trip to Zurich to visit family and also a chance to see the new natural history museum (NMZ) of the UZH! #FossilFriday

I made it!

☠ art! Lion and red fox back in the day when I had time to draw and paint #SciArt

I might be a bit late to the party, but here's my blue art! #PaleoArt #SciArt 🐡

Let's see if the pastures are greener over here...
Hi everyone I'm Oliver and I'm new here! I am a scientific illustrator and evolutionary biomechanist. I currently study the evolution of bird flight and I also draw and paint dead things ☠🦖🐦. Expect #PaleoArt / #SciArt, #Science and #Fossils!