On the 3D Nature of the Magpie (Aves: Pica pica) Functional Hindlimb Anatomy During the Take-Off Jump

Take-off is a critical phase of flight, and many birds jump to take the air. Although actuation hindlimb in terrestrial not limited sagittal plane, considerable non-sagittal plane motion has been observed during take-off jumps, how spatial arrangement muscles flying facilitates such jumps received little attention. This study aims ascertain 3D hip muscle function magpie ( Pica pica ), bird known take-off. A musculoskeletal model was developed using μCT scans (isotropic resolution 18.2 μm) derive bone surfaces, while path definition further informed by literature. Function robustly characterized determining moment-generating capacity 14 over functional joint range leap considering variations across attachment areas uncertainty dynamic geometry. Ratios peak flexion-extension (FE) internal-external rotation (IER) abduction-adduction (ABD) were indicators function. Analyses 972 paths showed that 11 can act as either flexor or extensor, all demonstrated internal external rotators with mean ratios FE IER ABD 0.89 0.31, respectively. Moment-generating approaching levels determined here underline avian plane. Together previous findings on nature kinematics, our results suggest models develop more detailed understanding orchestrate use cannot be restricted