This paper is an exploration of the space-geometry of hand motions as they relate to young men in the seated posture. It is primarily a presentation in functional anthropometry, but the information derived should have practical use in improving the design of work areas. The pilot of an airplane, the driver of an automobile, the assembly worker or the machine operator all perform critical tasks with their hands. Controls and switches or objects upon which work is to be done must not merely be within reach, they should also be placed in the best possible spatial position relative to the operator. This ideal position has not yet been prescribed.A detailed job analysis of a specific manual operation should of course improve the work area materially, but this information has little transfer value to another situation. Our work is concerned with the general range of hand motion, and we have attempted to find principles applicable to all work situations involving the seated position.The approach is anthropometric-but in an entirely different sense from traditional anthropometry. Our measurements of the space within reach of the seated subject for all possible upper limb postures represent an approach to a dynamic anthropometry. The method of measurement is indirect, and it involves a certain novelty in anthropometric procedure; this shows up especially in the methods of gathering raw data, of making measurements, and of treating data.

Forty young (23-day-old) and thirty old (1-year-old) male rats were castrated and sacrificed with controls at intervals up to 18 months of age. No differences were observed between femurs or mandibles of rats castrated at 23 days and those of controls. Year-old castrate rats developed femoral osteoporosis after 2 months, which became more pronounced 4 months after castration. This was characterized by reductions in femoral density, dry weight, dry weight per unit length, and ash weight, and by the appearance of resorption cavities in diaphyseal walls and a sparsity of trabeculae in metaphyses and epiphyses of castrate femurs. These results indicate that the year-old castrate male rat may be a valuable experimental model for studies of the treatment of osteoporosis.

The cetacean humerus is a short, robust bone without an open medullary cavity. It lies in the base of the resilient, streamlined pectoral limb (flipper) between the only free articulation (the glenohumeral) and approximately the body contour. The humerus is acted upon by muscles of the shoulder complex and receives loadings from the flattened distal portion of the limb as this hydroplane acts against body inertia and water resistance in control of body attitude.This study is an analysis of development and structure of the humerus in terms of the unique functional role of the flipper of finback, beluga and pilot whales. Gross external and internal architecture are depictued by photographs and by whole bone and frontal section radiographs. Structural density (bone/unit volume of humerus, with mineral content known to be constant) is analyzed indirectly by photodensitometry of standardized radiographs of sawed sections. Results are shown in graphic reconstructions of sections and of the whole bone. By comparison of radiodensity with the actual weight/volume of excised samples, sections are also reconstructed in terms of absolute density distribution.It is found that the spongy cetacean humerus, from its origin, is without central resorption and that its definitive structure is produced primarily by differential concentration of bone along endoectad gradients of porosity. Thus, the greatest concentration of bone is on medial and lateral sides while bone only half as dense fills the anterior and posterior sides and underlies the most dense regions. The core region is extremely porous. Within the biological context, this is a most reasonable approximation of the engineered box-beam as employed in some aircraft wings. Whole bone and frontal section radiographs show that, within this overall density pattern, the distribution of bone trabeculae resembles the classic illustrations of trajectories in the loaded beam.The ontogenetic and phylogenetic factors with possible bearing on this type of bone development and structure are discussed.