Ascending Tracts of Spinal Cord PDF

# Ascending Tracts The image describes the ascending tracts of the spinal cord. ## Ascending Tracts #Eoms 1. **Lateral Spinothalamic Tract** 2. **Anterior Spinothalamic Tract** 3. **Fasciculus Gracilis (Medially)** 4. **Fasciculus Cuneatus (Laterally)** 5. **Dorsal Spinocerebellar Tract** 6. **Ven...

# Ascending Tracts The image describes the ascending tracts of the spinal cord. ## Ascending Tracts #Eoms 1. **Lateral Spinothalamic Tract** 2. **Anterior Spinothalamic Tract** 3. **Fasciculus Gracilis (Medially)** 4. **Fasciculus Cuneatus (Laterally)** 5. **Dorsal Spinocerebellar Tract** 6. **Ventral Spinocerebellar Tract** 7. **Spino-Olive Tract** 8. **Spinotectal Tract** ## Sensation #Eoms - **Crude** - Touch - Pain - Temperature - Pressure - **Fine** - Tactile Localization - Tactile Discrimination - Stereognosis - Vibration - Proprioception - sense of position in space **Sensation goes out to brain with help of different orders of neurons.** - **1st Order Neuron** - **2nd Order Neuron** - **3rd Order Neuron** ## Lateral Spinothalamic Tract #Eoms The lateral spinothalamic tract carries the sensation of pain and temperature. - **First Order Nerve Neuron Fibres** start in the **Dorsal Root Ganglion** - **They relay** by synapsing with neurons in **Dorsal Horn of Grey Matter** of the **Spinal Cord (Substantia Gelatinosa)** - **Second Order Neuron Fibres** cross to **opposite side** close to **central canal** and ascend as **tract in lateral white column** of **Spinal Cord** - **Third Order Neuron** in **Thalamus (Ventroposterolateral nucleus)** - **Brain (area 3,1,2)** ## Anterior Spinothalamic Tract #Eoms The anterior spinothalamic tract carries fibres for crude touch & pressure. - **1st Neuron fibres** are in **Dorsal Root Ganglion** - **They relay** in **Grey Matter of Post. Horn (Nucleus Proprius)** - **Second Order Neurons** ascend for 1-2 segments & cross to the opposite side in **white column** and ascend further as **Ant. Spinothalamic Tract** **=Thalamus (3rd order neuron) (VPN nucleus)** - **Brain (area 3,1,2)** ## Fasciculus Gracilis (Tract of Gall) #Eoms The fasiculus gracilis commences at the **Caudal Limit of Spinal Cord**. - **1st order neuron fibres** start from **Dorsal Root Ganglion** - **They run directly upwards** in the **posterior column of white matter of spinal cord** (without relaying in the **spinal grey matter**) - **As the tract ascends, it receives fibres** from each **Dorsal Root** - **Fibres** which enter at **coccygeal & lower sacral region** are pushed medially by fibres which enter at **higher levels** ## Fasciculus Cuneatus (Tract of Burdack) #Eoms The fasiculus cuneatus commences in **mid-thoracic region** and derives its fibres from **thoracic & cervical segments.** - **Dorsal Root Ganglion** - **Nucleus Cuneatus** - **Thalamus** - **Brain (312)** ## VPL (Ventroposterolateral Nucleus) #Eoms | | **1st Order Neuron** | **2nd Order Neuron** | **3rd Order Neuron** | |---------------|----------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------|----------------------------------------------------------------------------| | **Crude Sensation** | **Dorsal Root Ganglion** | **Dorsal Horn Cell (Substantia Gelatinosa)** | **Thalamus (VPL nucleus)** | | **Fine Sensation** | **Dorsal Root Ganglion** | **Nucleus Gracilis & N. Cuneatus** | **Thalamus (VPL Nucleus) - Ventroposterolateral nucleus** | **Syringomyelia - Cavities formed near central canal** - **Damage the crossing fibres** of crude sensation - **lost** - **Dissociated Sensory Loss** (`Fine sensation is not lost`) **Ant. & Lat. Spinothalamic Tract carries **extroseptive sensations** from **opposite half of body**. #Eoms - **They lie in continuity** with each other in the **antero lateral white column of spinal cord**. - **Sensations** of pressure, touch, temperature and pain - **Medial & Lateral**.