Point 3


Intro

Pathway

Deficits

Optional

Summary

Problems


Contents

Anatomy

 

 

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A lesion of the DSCT at C2 will result in incoordination of muscles innervated by spinal segments C8 and below. Such a lesion will not affect the coordination of muscles innervated by spinal segments C1-C7. Also, remember, there is NO DSCT below L3. A couple of more points. What about a lesion of the fasciculus gracilis at L4? Well, you know that there will be a loss of conscious proprioception from L4 and below on the ipsi. side from interrupting the alpha-betas axons. This will result in a loss of 2 point discrimination, vibration and conscious proprioception and incoordination. But don't forget that the 1a, 1b and II fibers from L4 and below are in the fasc. gracilis at L4 just waiting to dive into Clarke's column at L3. So, a lesion of fasc. gracilis at L4 will also result in a loss of unconscious proprioception from spinal segment L4 and below. This will add more incoordination to that resulting from the interruption of the alpha-betas. What about a lesion of only fasciculus cuneatus at C2. Well, alpha-beta fibers from C2-T6 (C1 has no dorsal root) are interrupted and thus there is loss of 2 point discrimination, vibration and conscious proprioception. Also, remember there is incoordination. In addition, the 1a, 1b and IIs from spinal segments C7 to C2 (remember, Clarke's column ends at C8) are headed for the accessory cuneate nucleus in the medulla and will never make it. This will result in a loss of unconscious proprioception from C7-C2 and incoordination of muscles associated with these spinal segments. Thus, C7-C2 has incoordination from loss of alpha-beta and 1a, 1b and IIs, while C7-T6 has incoordination from losing only the alpha-betas.