Using computerized motion analysis techniques, kinematics of foot trajectories were quantitatively analyzed in twelve rats before and after dorsal spinal cord hemisection at the T6 level. Although overground locomotion in these animals returned to normal within four weeks, some kinematic variables during treadmill locomotion did not recover to pre-lesion level. Immediately following dorsal hemisection, amplitudes of both hindfeet horizontal and vertical movements were dramatically reduces. However, in three weeks, the amplitudes of horizontal movement(stride length) became significantly larger than of pre-lesion strides. On the other hand, amplitude of hindlimb vertical movement showed very little recovery. Forelimb-hindmill coordination was also disrupted initially but returned to normal within three weeks. The duration of hindlimb swing phase became significantly longer after sectioning and gradually recovered, but never to pre-lesion levels. Interestingly, amplitudes of forelimb vertical movement. which was depressed initially, became significantly largery three weeks after lesioning. A dramatic increase in the statistical variation of limb kinematics, which persisted even after motor recovery, is an important parameter for the evaluation of neural deficits in spinal cord injuries. Kinematic analysis is a sensitive technique for the detection of minor motor deficits following nerve injuries.
Animals ; Biomechanical Phenomena ; Extremities ; Foot ; Forelimb ; Hand ; Hindlimb ; Locomotion* ; Rats* ; Spinal Cord Injuries ; Spinal Cord*