Anatomical diagrams illustrating the organization of major white matter tracts in the human spinal cord across cervical, thoracic, and lumbar cross-sections. A primary large-scale diagram provides detailed labeling of pathways, while three comparative smaller diagrams show regional variations. Descending (motor) pathways are color-coded in orange (corticospinal tracts from the cerebral cortex) and grey/black (brainstem-derived tracts including rubrospinal, reticulospinal, and tectospinal tracts). Ascending (sensory) pathways are highlighted in blue for dorsal columns (fasciculus gracilis and cuneatus), green for dorsal and ventral spinocerebellar tracts, and pink for the spinothalamic and spinoreticular tracts. The diagrams illustrate key neuroanatomical landmarks such as the central canal (CC), dorsal horns, and ventral horns. Educational focus is placed on the somatotopic arrangement and the relative change in white matter volume versus grey matter across different spinal levels, highlighting the clinical relevance for localized spinal cord injury and neurological deficit mapping.

This medical anatomical diagram illustrates a transverse section of the human spinal cord, specifically detailing the organization of white matter tracts. The visual uses a color-coded schema to differentiate between motor and sensory pathways: descending (efferent) motor tracts are highlighted in red, while ascending (afferent) sensory tracts are shown in blue. Key anatomical structures identified include the Pyramidal tracts (lateral and anterior corticospinal tracts), Extrapyramidal tracts (rubrospinal, reticulospinal, olivospinal, and vestibulospinal), the Dorsal Column-Medial Lemniscus system (gracile and cuneate fasciculi), Spinocerebellar tracts, and the Anterolateral system (lateral and anterior spinothalamic tracts). A significant educational feature of the diagram is the depiction of somatotopic organization, showing the concentric arrangement of sacral, lumbar, thoracic, and cervical fibers within the lateral corticospinal and dorsal column tracts. The image provides a comprehensive overview of spinal cord neuroanatomy, useful for understanding clinical localization of spinal cord lesions and the functional topography of the central nervous system.

This Comparison Diagram presents a cross-sectional illustration of the spinal cord, contrasting the localization of axonal spheroids and neuronal loss in Neuroaxonal Dystrophy (NAD) and Hereditary Spastic Paraplegia (HSP). The diagram is split into two halves: the left represents a Spanish Water Dog with NAD, and the right represents human HSP. Ascending sensory pathways are highlighted in red, including the Gracile Fasciculus (GF), Cuneate Fasciculus (CF), and Dorsal Horn (DH) on the NAD side, and GF, Dorsal Spinocerebellar Tract (DST), and Ventral Spinocerebellar Tract (VST) on the HSP side. Descending motor pathways, affected only in the HSP model, are highlighted in blue, depicting the Lateral Corticospinal Tract (LCT), Ventral Corticospinal Tract (VCT), and Ventral Horn (VH). The visual demonstrates that in NAD, pathology is restricted to sensory, ascending tracts in the dorsal funiculus and dorsal horn. In contrast, human HSP shows involvement of both sensory pathways and descending motor pathways (pyramidal tracts and ventral horns). This diagram illustrates the pathophysiology of upper motor neuron and sensory system degeneration relevant to neurology and neurohistology.

An anatomical diagram illustrating the descending motor pathways from the brain to the skeletal muscle. The visual highlights the relationship between the central and peripheral nervous systems. Key structures labeled include the motor cortex (the origin of voluntary movement), the internal capsule, the brainstem, and the spinal cord. Two distinct neural tracts are color-coded: a red pathway representing the pyramidal tract for voluntary muscle control, and a black pathway representing involuntary or extrapyramidal motor systems. These pathways descend through the brainstem into the spinal cord, where they synapse with a peripheral nerve. The diagram further details the innervation of a muscle fiber, showing the motor ending (neuromuscular junction) and a sensory spindle, illustrating the feedback loop between muscle tension and the spinal cord. This infographic is designed to teach the neuroanatomical distinction between voluntary and involuntary motor control and the physical sequence of nerve conduction.