Limb movements in a monotreme (Tachyglossus aculeatus): a cineradiographic analysis.
In a walking echidna the principal movement of the humerus is long-axis rotation. The humerus remains approximately perpendicular to the sagittal plane, but the femur is directed anterolaterally at angles from 35 degrees to 50 degrees . In addition to long-axis rotation, the femur elevates and depresses in an arc which usually varies between 40 degrees and 90 degrees . The femoral angle, the femoral elevation and depression, and the plantar contact of the manus beneath the glenoid are features found also in generalized therians.
D000818:Animals; D005121:Extremities / Q000000981:diagnostic imaging / Q000502:physiology*; D005269:Femur; D005552:Forelimb; D006614:Hindlimb; D009040:Motion Pictures; D009068:Movement; D010388:Pelvis; D011859:Radiography; D012399:Rotation; D012785:Shoulder Joint; D004490:Xenarthra / Q000502:physiology*