Abstract: In the diagnostic evaluation of the measurement of head rotations for the functional examination of the cervical portion of the spine and the upper dorsal column it is to be noted that the head rotates not only with reference to that axial system which corresponds to the measuring system arranged between the holder and the supporting device, but also performs a three-dimensional movement in space. When tilting the head, e.g., the same not only rotates about a horizontal, frontal axis (parallel ear-to-ear) but also moves forward and downward. Even more complex are rotary or lateral tilting movements of the head which, beyond a certain extend of displacement, proceed only with a three-dimensional motion of the head. Yet the rotations of the head in a broader sense, including the ancillary movements referred to, are what permits more accurate conclusions as to the function of the spine. Analogous conditions apply to other sequences of movement with multijointed motion progressions, e.g. of the extremities.

Abstract: A protection arrangement for a casting jet emerging from a metallurgical vessel includes a protective tube enveloping the casting jet and fastened to an articulation-rod assembly that is pivotable into any space direction. In order to be able to follow any desired position of the casting jet with the protective tube, the articulation-rod assembly includes a first, vertically extending, four-bar linkage parallelogram which is mounted with its vertically arranged web so as to be rotatable about a vertical axis. To its coupler, an extension arm carrying the protective tube is hinged, forming the oscillating crank of a second four-bar linkage. The web of the second four-bar linkage is formed by an oscillating crank of the first four-bar linkage parallelogram.