. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LEG EXTENSION IN LIMULUS DETERMINATION OF PRESSURE REQUIRED FOR EXTENSION Methods The pressure required to extend hydraulically the femoro-patellar joint of a detached leg was determined by the following procedure. Legs were excised from nine live specimens of Limulus at the base of the trochanter; the leg haemocoel was then closed off with a rubber stopper (see Fig. 3) and the internal pressure was then increased by injecting saline with a syringe into the closed system. Simultaneously, the internal pressure in the leg was
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. LEG EXTENSION IN LIMULUS DETERMINATION OF PRESSURE REQUIRED FOR EXTENSION Methods The pressure required to extend hydraulically the femoro-patellar joint of a detached leg was determined by the following procedure. Legs were excised from nine live specimens of Limulus at the base of the trochanter; the leg haemocoel was then closed off with a rubber stopper (see Fig. 3) and the internal pressure was then increased by injecting saline with a syringe into the closed system. Simultaneously, the internal pressure in the leg was monitored and the change in femoro-patellar joint angle was measured with a protractor. Measurements of the pressure through the membrane of the hinge joint and through the exoskeleton gave the same results to pressure transducer. tygon tubing FIGURE 3. Determination of pressure required for extension. as measurements through the stopper. Subsequent measurements were therefore made through the stopper, which was more convenient. Results The pressures measured in vivo in the legs are much smaller than the pressures required to extend the hinge joint hydraulically. Figure 4 shows the pressure required for extension of the femoro-patellar joint determined for nine animals. The pressure needed to produce the observed extension of about 50 degrees in this position was about 150 mm Hg according to this graph. Also on Figure 4 are the mean in vivo leg blood pressures. These means are the normal blood pressures described above, measured in vivo in the leg while the femoro-patellar joint is fully flexed and while it is fully extended. The mean leg blood pressures are only enough to account for about a three-degree change in joint angle. In no case did the in vivo leg pressures reach a value that could account for a ten-degree extension as determined by the graph, whereas normal extensions by the animal ranged from 35 to 71 degrees under these conditions. Cutting all the flexors reduced
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
