Anatomy of the Spinal Cord The ascending and descending tracts Anatomy of the Spinal Cord The ascending and descending tracts

White Matter White Matter Anterior Funiculus (Anterior White Column) Anterior Funiculus (Anterior White Column) Posterior Funiculus (Posterior White Column) Posterior Funiculus (Posterior White Column) Fasciculus Gracilis & Fasciculus Cuneatus Fasciculus Gracilis & Fasciculus Cuneatus Lateral Funiculus (Lateral White Column) Lateral Funiculus (Lateral White Column) Gray Matter Gray Matter Anterior Horn motor Anterior Horn motor Posterior Horn sensory Posterior Horn sensory Lateral Horn autonomic Lateral Horn autonomic Gray Commissure anterior and posterior Gray Commissure anterior and posterior White Matter White Matter Anterior Funiculus (Anterior White Column) Anterior Funiculus (Anterior White Column) Posterior Funiculus (Posterior White Column) Posterior Funiculus (Posterior White Column) Fasciculus Gracilis & Fasciculus Cuneatus Fasciculus Gracilis & Fasciculus Cuneatus Lateral Funiculus (Lateral White Column) Lateral Funiculus (Lateral White Column) Gray Matter Gray Matter Anterior Horn motor Anterior Horn motor Posterior Horn sensory Posterior Horn sensory Lateral Horn autonomic Lateral Horn autonomic Gray Commissure anterior and posterior Gray Commissure anterior and posterior Spinal Cord Internal Structure Spinal Cord Internal Structure

1. posterior horn 2. anterior horn 3. intermediate zone (intermediate gray) (intermediate gray) 4. lateral horn 5. posterior funiculus 6. anterior funiculus 7. lateral funiculus 8. Lissauer's tract 9. anterior median 9. anterior median fissure fissure 10. posterior median sulcus sulcus 11. anterolateral sulcus sulcus 12. posterolateral sulcus sulcus 13. Posterior intermediate intermediate sulcus sulcus

Lamina of Rexed Lamina of Rexed Lamina I posteromarginal nucleus Lamina I posteromarginal nucleus Lamina II substantia gelatinosa Lamina II substantia gelatinosa Lamina III, IV nucleus proprius Lamina III, IV nucleus proprius Lamina V, VI Clarke’s column (Nucleus dorsalis) Lamina V, VI Clarke’s column (Nucleus dorsalis) Lamina VII intermediate gray Lamina VII intermediate gray intermediolateral cell column (ILM) intermediolateral cell column (ILM) intermediomedial cell column (IMM) intermediomedial cell column (IMM) Lamina VIII------interneurons Lamina VIII------interneurons Lamina IX anterior horn (motor) cell Lamina IX anterior horn (motor) cell Lamina X gray commissure Lamina X gray commissure Lamina of Rexed Lamina of Rexed Lamina I posteromarginal nucleus Lamina I posteromarginal nucleus Lamina II substantia gelatinosa Lamina II substantia gelatinosa Lamina III, IV nucleus proprius Lamina III, IV nucleus proprius Lamina V, VI Clarke’s column (Nucleus dorsalis) Lamina V, VI Clarke’s column (Nucleus dorsalis) Lamina VII intermediate gray Lamina VII intermediate gray intermediolateral cell column (ILM) intermediolateral cell column (ILM) intermediomedial cell column (IMM) intermediomedial cell column (IMM) Lamina VIII------interneurons Lamina VIII------interneurons Lamina IX anterior horn (motor) cell Lamina IX anterior horn (motor) cell Lamina X gray commissure Lamina X gray commissure Spinal Cord Internal Structure Spinal Cord Internal Structure

Lamina of Rexed

Ascending Tracts Ascending Tracts Modality: Touch, Pain, Temperature, pressure Modality: Touch, Pain, Temperature, pressure Receptor: Exteroceptor, Proprioceptor Receptor: Exteroceptor, Proprioceptor Primary Neuron: Dorsal Root Ganglion (Spinal Ganglion) Primary Neuron: Dorsal Root Ganglion (Spinal Ganglion) Secondary Neuron: Spinal Cord or Brain Stem Secondary Neuron: Spinal Cord or Brain Stem (Tertiary Neuron): Thalamus (Ventral posterolateral Nucleus) (Tertiary Neuron): Thalamus (Ventral posterolateral Nucleus) Termination: Cerebral Cortex Termination: Cerebral Cortex Ascending Tracts Ascending Tracts Modality: Touch, Pain, Temperature, pressure Modality: Touch, Pain, Temperature, pressure Receptor: Exteroceptor, Proprioceptor Receptor: Exteroceptor, Proprioceptor Primary Neuron: Dorsal Root Ganglion (Spinal Ganglion) Primary Neuron: Dorsal Root Ganglion (Spinal Ganglion) Secondary Neuron: Spinal Cord or Brain Stem Secondary Neuron: Spinal Cord or Brain Stem (Tertiary Neuron): Thalamus (Ventral posterolateral Nucleus) (Tertiary Neuron): Thalamus (Ventral posterolateral Nucleus) Termination: Cerebral Cortex Termination: Cerebral Cortex Spinal Cord Tracts Spinal Cord Tracts

Ascending Tracts Ascending Tracts Posterior White Column-Medial Lemniscal Pathway Posterior White Column-Medial Lemniscal Pathway Spinothalamic Tract Spinothalamic Tract Spinoreticular Tract Spinoreticular Tract Spinocerebellar Tract Spinocerebellar Tract Spino-olivary Tract Spino-olivary Tract Spinotectal Tract Spinotectal Tract Ascending Tracts Ascending Tracts Posterior White Column-Medial Lemniscal Pathway Posterior White Column-Medial Lemniscal Pathway Spinothalamic Tract Spinothalamic Tract Spinoreticular Tract Spinoreticular Tract Spinocerebellar Tract Spinocerebellar Tract Spino-olivary Tract Spino-olivary Tract Spinotectal Tract Spinotectal Tract Spinal Cord Tracts Spinal Cord Tracts

Spinothalamic Tract Modality: Pain & Temperature Sensation, Light Touch, pressure Modality: Pain & Temperature Sensation, Light Touch, pressure Receptor: Free Nerve Ending Receptor: Free Nerve Ending Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root Posterior Root 2nd Neuron: Dorsal Horn 2nd Neuron: Dorsal Horn Spinothalamic Tract - (Spinal Lemniscus) Spinothalamic Tract - (Spinal Lemniscus) 3rd Neuron: Thalamus 3rd Neuron: Thalamus Internal Capsule Corona Radiata Internal Capsule Corona Radiata Termination: Primary Somesthetic Area (S I) Termination: Primary Somesthetic Area (S I) Spinothalamic Tract Modality: Pain & Temperature Sensation, Light Touch, pressure Modality: Pain & Temperature Sensation, Light Touch, pressure Receptor: Free Nerve Ending Receptor: Free Nerve Ending Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root Posterior Root 2nd Neuron: Dorsal Horn 2nd Neuron: Dorsal Horn Spinothalamic Tract - (Spinal Lemniscus) Spinothalamic Tract - (Spinal Lemniscus) 3rd Neuron: Thalamus 3rd Neuron: Thalamus Internal Capsule Corona Radiata Internal Capsule Corona Radiata Termination: Primary Somesthetic Area (S I) Termination: Primary Somesthetic Area (S I) Spinal Cord Ascending Tracts Spinal Cord Ascending Tracts

Spinothalamic Tract spinothalamictract anterior white commissure posterior root decussation - contralateral loss of pain and temperature sensation below the level of lesion sensation below the level of lesion

Fast PainSlow Pain Fast PainSlow Pain Sharp, prickingDull, burning (A  ) fiber (C) fiber Short latencySlower onset Well localizedDiffuse Short durationLong duration Less emotional Emotional, autonomic response Not blocked by morphineBlocked by morphine Comparison of Fast and Slow Pain Spinothalamic Tract Comparison of Fast and Slow Pain Spinothalamic Tract

Posterior White Column-Medial Lemniscal Pathway Modality: Discriminative Touch Sensation (include Vibration) and Modality: Discriminative Touch Sensation (include Vibration) and Conscious Proprioception (Position Sensation) Conscious Proprioception (Position Sensation) Receptor: Most receptors except free nerve endings Receptor: Most receptors except free nerve endings Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root - Posterior White Column Posterior Root - Posterior White Column 2nd Neuron: Dorsal Column Nuclei (Nucleus Gracilis et Cuneatus) 2nd Neuron: Dorsal Column Nuclei (Nucleus Gracilis et Cuneatus) Internal Arcuate Fiber - Lemniscal Decussation Internal Arcuate Fiber - Lemniscal Decussation - Medial Lemniscus - Medial Lemniscus 3rd Neuron: Thalamus 3rd Neuron: Thalamus Internal Capsule Corona Radiata Internal Capsule Corona Radiata Termination: Primary Somesthetic Area (S I) Termination: Primary Somesthetic Area (S I) Posterior White Column-Medial Lemniscal Pathway Modality: Discriminative Touch Sensation (include Vibration) and Modality: Discriminative Touch Sensation (include Vibration) and Conscious Proprioception (Position Sensation) Conscious Proprioception (Position Sensation) Receptor: Most receptors except free nerve endings Receptor: Most receptors except free nerve endings Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root - Posterior White Column Posterior Root - Posterior White Column 2nd Neuron: Dorsal Column Nuclei (Nucleus Gracilis et Cuneatus) 2nd Neuron: Dorsal Column Nuclei (Nucleus Gracilis et Cuneatus) Internal Arcuate Fiber - Lemniscal Decussation Internal Arcuate Fiber - Lemniscal Decussation - Medial Lemniscus - Medial Lemniscus 3rd Neuron: Thalamus 3rd Neuron: Thalamus Internal Capsule Corona Radiata Internal Capsule Corona Radiata Termination: Primary Somesthetic Area (S I) Termination: Primary Somesthetic Area (S I) Spinal Cord Ascending Tracts Spinal Cord Ascending Tracts

Posterior White Column - Medial Lemniscal Pathway Posterior White Column - Medial Lemniscal Pathway medial lemniscus lemniscal decussation internal arcuate fiber posterior white column posterior root - ipsilateral loss of discriminative touch sensation and conscious proprioception sensation and conscious proprioception below the level of lesion below the level of lesion

Spinocerebellar Tract Modality: Unconscious Proprioception Modality: Unconscious Proprioception Receptor: Muscle spindle, Golgi tendon organ Receptor: Muscle spindle, Golgi tendon organ Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root, [Posterior Column] Posterior Root, [Posterior Column] 2nd Neuron: Clarke’s column 2nd Neuron: Clarke’s column Posterior Spinocerebellar Tract Posterior Spinocerebellar Tract Anterior Spinocerebellar Tract Anterior Spinocerebellar Tract Termination: Cerebellar Cortex Termination: Cerebellar Cortex Spinocerebellar Tract Modality: Unconscious Proprioception Modality: Unconscious Proprioception Receptor: Muscle spindle, Golgi tendon organ Receptor: Muscle spindle, Golgi tendon organ Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Ist Neuron: Dorsal Root Ganglion (Spinal Ganglion) Posterior Root, [Posterior Column] Posterior Root, [Posterior Column] 2nd Neuron: Clarke’s column 2nd Neuron: Clarke’s column Posterior Spinocerebellar Tract Posterior Spinocerebellar Tract Anterior Spinocerebellar Tract Anterior Spinocerebellar Tract Termination: Cerebellar Cortex Termination: Cerebellar Cortex Spinal Cord Ascending Tracts Spinal Cord Ascending Tracts

Spinocerebellar Tract

Corticospinal Tract Origin: Cerebral Cortex Origin: Cerebral Cortex Brodmann Area 4 (Primary Motor Area, M I) Brodmann Area 4 (Primary Motor Area, M I) Brodmann Area 6 (Premotor Area, PM ) Brodmann Area 6 (Premotor Area, PM ) Brodmann Area 3,1,2 (Primary Somesthetic Area, S I) Brodmann Area 3,1,2 (Primary Somesthetic Area, S I) Corona Radiata Corona Radiata lnternal Capsule, Posterior Limb lnternal Capsule, Posterior Limb Crus Cerebri, Middle Portion Crus Cerebri, Middle Portion Pyramid - pyramidal decussation Pyramid - pyramidal decussation Corticospinal Tract - Lateral and Anterior Corticospinal Tract - Lateral and Anterior Termination: anterior gray horn Termination: anterior gray horn Corticospinal Tract Origin: Cerebral Cortex Origin: Cerebral Cortex Brodmann Area 4 (Primary Motor Area, M I) Brodmann Area 4 (Primary Motor Area, M I) Brodmann Area 6 (Premotor Area, PM ) Brodmann Area 6 (Premotor Area, PM ) Brodmann Area 3,1,2 (Primary Somesthetic Area, S I) Brodmann Area 3,1,2 (Primary Somesthetic Area, S I) Corona Radiata Corona Radiata lnternal Capsule, Posterior Limb lnternal Capsule, Posterior Limb Crus Cerebri, Middle Portion Crus Cerebri, Middle Portion Pyramid - pyramidal decussation Pyramid - pyramidal decussation Corticospinal Tract - Lateral and Anterior Corticospinal Tract - Lateral and Anterior Termination: anterior gray horn Termination: anterior gray horn Spinal Cord Descending Tracts Spinal Cord Descending Tracts

Descending Tracts from Brain Stem lateral (Motor) Pathway lateral (Motor) Pathway Rubrospinal Tract Rubrospinal Tract medial (Motor) Pathway medial (Motor) Pathway Tectospinal Tract Tectospinal Tract Vestibulospinal Tract Vestibulospinal Tract Descending Tracts from Brain Stem lateral (Motor) Pathway lateral (Motor) Pathway Rubrospinal Tract Rubrospinal Tract medial (Motor) Pathway medial (Motor) Pathway Tectospinal Tract Tectospinal Tract Vestibulospinal Tract Vestibulospinal Tract Spinal Cord Descending Tracts Spinal Cord Descending Tracts

Reticulospinal tracts: Origin: brain stem Pontine, medullary reticulospinal tracts termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons Reticulospinal tracts: Origin: brain stem Pontine, medullary reticulospinal tracts termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons

tectospinal tracts: Origin: superior colliculus of midbrain termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons tectospinal tracts: Origin: superior colliculus of midbrain termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons

Rubrospinal tracts: Origin:red nucleus termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons Rubrospinal tracts: Origin:red nucleus termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons

vestibulospinal tracts: Origin: vestibular nuclei termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons vestibulospinal tracts: Origin: vestibular nuclei termination: anterior gray column termination: anterior gray column alpha and gamma motor neurons alpha and gamma motor neurons

Upper Motor Neuron (UMN) vs Lower Motor Neuron (LMN) Syndrome UMN syndrome LMN Syndrome Type of Paralysis Spastic Paresis hypertonia Flaccid Paralysis hypotonia Atrophy No (Disuse) Atrophy Severe Atrophy Deep Tendon Reflex Increase Absent DTR Pathological Reflex Positive Babinski Sign Absent Superficial Reflex Absent Present Fasciculation and Absent Could be Fibrillation Present