Study on the Structural Characteristics of Bird Necks and Their Static Motion Features in the Sagittal Plane

Abstract

The necks of birds that possess complex structures, graceful curves, and flexible movements are perfect natural motion actuators. Studying their structural features, mechanic characteristics, and motion rules can provide valuable references for imitating such actuators and motion functions artificially. Previous studies have analyzed the influence of two-dimensional motion geometric features and anatomical structure of the neck on motion efficiency and motion stability. However, the mechanism of motion flexibility from the perspective of neck structure has not been investigated. This study investigates the general law of the relationship between the structural parameters and motion characteristics of birds’ necks using tomography technology and 3D reconstruction technology. The results show that the structural characteristics of geese and ducks are similar, and there are significant differences in joint motion characteristics. Geese obtains complex neck postures through active intervertebral joints and highly flexible facet joints and possesses higher neck flexibility than ducks. This study provides a generic measuring method for obtaining birds’ cervical spinal vertebral structural dimensional parameters and offers a new theoretical concept for bionic robotic structural design and manufacture.

The neck as a keystone structure in avian macroevolution and mosaicism

“…The forelimb elements included in this study are coracoid, scapula, humerus, radius, ulna and carpometacarpus. This simplified measure of forelimb morphology (element length and the relative proportions of these forelimb element lengths) adequately captures the main axes of variation in forelimb bone morphology [ 64 ] and has been repeatedly shown to correlate with flight style [ 47 , 77 – 79 ]. Forelimb measurements were body size corrected by utilizing the following formula forelimb element/body mass^0.33, and head mass was taken as a percentage of total body mass.…”

In Vivo Analysis of the Dynamic Motion Stability Characteristics of Geese’s Neck

“…The unique joint structure of the bird’s neck allows for a significant degree of movement in dorsoventral flexion and extension and lateral flexion, but is limited in axial rotational movement [ 11 ]. Studies on the morphological characteristics of the avian neck have focused on skeletal muscles [ 12 , 13 , 14 , 15 ] and genetic evolution. Krings et al used X-ray and CT scanning techniques to simultaneously acquire 3D head movements and 3D 14-segment cervical vertebrae (C1–C14) models of American barn owls to quantify the morphological characteristics of individual vertebrae, including cervical spinal canal diameter and articular protrusion, intervertebral joint parameters including joint center distance, and pitch angle [ 16 ].…”