Spinal Cord Tracts
Terms
undefined, object
copy deck
- Corticospinal Tract
-
-Begins in motor/premotor cortex
-Travels through ipsilateral internal capsule (cerebrum), cerebral peduncle (midbrain), medullary Pyramid
-Lateral decussates at medullary pyramid(75-90%), Anterior decussates at spinal cord level (10-25%)
-Synapse on motor neurons (10%) or interneurons (90%) in spinal cord - Rubrospinal Tract
-
-Controls distal flexor tone, modulation of ongoing movement
-Originates in Red Nucleus (midbrain)
-Decussates at Ventral Tegmental Decussation (midbrain)
-Synapses on interneurons in laminae V-VIII - Reticulospinal Tract
-
-Modulates spinla reflexes, tone in axial muscles for posture
-Begins in Pontine and medullary reticular formation
-Pontien fibers descend uncrossed, medullary fibers can descend bilaterally
-Synapse on gray matter motor neurons and interneurons - Raphespinal Tract
-
-Modulation of pain transmission form spinal cord
-Begins in Dorsal Raphe Nucleus (midbrain)
-Decussates at midbrain level
-Synapses on interneurons in laminae I, II, V of s.c. - Tectospinal Tract
-
-Head posture, reflexes and movement in response to visual stimuli
-Begins in Superior Colliculus (midbrain)
-Decussates in Dorsal Tegmental Decussation(midbrain)
-Projects bilaterally to motor neurons of axial neck and trunk muscles
-Only in upper cervical levels - Medial Vesibulospinal Tract
-
-Head and neck posture (flexors)
-Begins in Medial Vestibular Nucleus (medulla) as a continuation of MLF
-No Decussation
-Projects to motor neurons (IX) and interneurons (VIII) in cervical spinal cord levels - Lateral Vestibulospinal Tract
-
-trunk posture/antgravity flexors
-Originates in Lateral vestibular nucleus (medulla)
-No Decussation
-Synapses on interneurons (VIII) and motor neurons (IX) mostly at lumbar levels - Dorsal Column System
-
-Fine touch, pressure, vibration, spatially discriminitive position
-Cell bodies in DRG
-Ascends as Fasciculus Cuneatus (arm-T6 and up) and Fasciculus Gracilis (leg)
-Synapse at Nucleus cuneatus and Nucleus Gracilis in medulla
-Decussates in medulla at pyramidal decussation
-Fibers cross as internal arcuate fibers and continue as the Medial Lemniscus
-Synapse in VPL nucleus of thalamus
-Continue to Somatosensory cortex of parietal lobe - Neospinothalamic Tract
-
-Part of ALS, crude pain, thermal sense, some crude touch
-sensors are free nerve endings that project to lamina II
-Cell bodies in Lam I and V
-Decussate at SC level
-Project to VPL nucleus in thalamus
-Continue to Somatosensory Cortex in parietal lobe - Paleospinothalamic tract
-
-Crude touch. Part of ALS.
-Free nerve endings project to Lamina II on interneurons
-cell bodies in Laminae VI-VIII
-Decussates at spinal cord level
-Projects to Intralaminar nucleus of thalamus
-Continues to Cingulate nucleus of frontal lobe - Spinomesencephalic Tract
-
-Modification of pain sensation at s.c. level
-Free nerve endings project to Lamina II
-Cell bodies in laminae I and V
-Decussates at SC level
-Ascends to mesencephalic Reticular Formation/Raphe nuclei in periaqueductal grey - Spinoreticular tract
-
-Part of ALS, crude pain
-Free nerve endings project to Lamina II
-Cell bodies in Laminae VI-VIII
-Decussates at spinal cord level
-Ascends to Reticular Formation where it follows a multisynaptic path to the thalamus - Dorsal Spinocerebellar Tract/Cuneocerebellar Tract
-
-Individual Muscle Sense
-Below C8:
-Muscle spindles/golgi tendon organs send fibers into s.c.
-Ascend to Clarke's Column/Nucleus Dorsalis (C8-L2) where cell bodies are located
-No Decussation
-Go to cerebellum through Inferior cerebellar Peduncle
-Above C8:
-Enter s.c. and ascend to External Cuneate Nucleus in medulla where cell bodies are located
-tract continues to cerebellum through Inferior Cerebellar Peduncle - Anterior Spinothalamic Tract
-
-Part of ALS, crude touch
-Free nerve endings project to Lamina II
-Cell bodies in dorsal horn, can project bilaterally
-Decussation at spinal cord level
-Ascends to VPL nucleus ot thalamus
-Continues to Somatosensory Cortex in Parietal Lobe - Ventral/Anterior Spinocerebellar Tract
-
-joint/limb muscle information
-Golgi tendon Organs project to Spinal Border cells (V-VII) in dorsal horn
-Decussate at spinal cord level and again in upper pons
-Continue to cerebellum through Superior Cerebellar Peduncle