PARALYSIS AND LONG-BONE GROWTH IN THE CHICK - GROWTH SHAPE TRAJECTORIES OF THE PELVIC LIMB

Growth of chick embryonic femora, tibiotarsi and first phalanges of di git three were measured at one day intervals from day 6 through 16 of incubation. Normal controls were compared to embryos paralyzed at 5 da ys of incubation. Over the 10 day study period, length of the paralyze d femora, length and width of the paralyzed tibiotarsi and differences in length of the phalanges were observed. Growth in length of phalanx one of digit three was most affected by paralysis over this period. C hanges in shape of these bones also occurred during growth. Normal lon g bones undergo changes in shape as differential growth in length and width occurs. Such changes in shape can be considered as the bone's no rmal growth ''trajectory''. Paralyzed bones displayed a different grow th trajectory than normal bones. As expected, the long bones of paraly zed embryos were shorter than age-matched controls. Contrary to expect ations, however, paralyzed long bones were relatively more stout than age-matched controls.