The axons of the corticospinal tract the condense to form the pyramids. The axons are arranged in a very orderly fashion. Axons which will innervate the muscles of the face are located medially. This tract is known as the corticobulbar tract. The axons which form the corticobulbar tract exit at their appropriate levels to synapse with their lower motor neurons in the cranial nerve nuclei.
The axons which will innervate the legs are located laterally within the cerebral peduncle. Thus the name "lateral corticospinal tract". These axons then aggegate to form the pyramids in the medulla. Thence the name "pyramidal tract".
An Introduction on the Corticospinal Tract
The video was used by permission of Paul D. Larsen, M.D., University of Nebraska Medical Center and Suzanne S. Stensaas, Ph.D., University of Utah School of Medicine. Additional materials were drawn from resources provided by Alejandro Stern, Stern Foundation, Buenos Aires, Argentina; Kathleen Digre, M.D., University of Utah; and Daniel Jacobson, M.D., Marshfield Clinic, Wisconsin. The movies are licensed under a Creative Commons Attribution-NonCommerical-ShareAlike 2.5 License.
Reference:
1. Motor Systems. http://pathology.mc.duke.edu/neuropath/nawr/motor-systems.html. Accessed: January 7, 2011.
Friday, January 7, 2011
Thursday, January 6, 2011
Video: Sensory Tracts
The Spinothalamic Tract
The Dorsal Column-Medial Lemniscus System
The following are used by permission of Paul D. Larsen, M.D., University of Nebraska Medical Center and Suzanne S. Stensaas, Ph.D., University of Utah School of Medicine. Additional materials were drawn from resources provided by Alejandro Stern, Stern Foundation, Buenos Aires, Argentina; Kathleen Digre, M.D., University of Utah; and Daniel Jacobson, M.D., Marshfield Clinic, Wisconsin. The movies are licensed under a Creative Commons Attribution-NonCommerical-ShareAlike 2.5 License.
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