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| | Upper Motor Neuron (UMN) Lesion | Lower Motor Neuron (LMN) Lesion | |---|---|---| | Muscle tone | Spasticity (clasp-knife) | Flaccidity | | Deep tendon reflexes | Hyperreflexia | Areflexia/hyporeflexia | | Plantar response | Extensor (Babinski +) | Flexor (normal) | | Muscle atrophy | Mild (disuse) | Severe | | Fasciculations | Absent | Present |
The posterior tract remains ipsilateral (un学习crossed), while the anterior tract decussates twice, ultimately ending up on the same side. 3. The Descending Tracts (Motor Pathways)
Occurs immediately at the level of entry in the spinal cord. C. Spinocerebellar Tracts ascending and descending tracts of spinal cord ppt
Transmits unconscious proprioception to the cerebellum, aiding in coordination and posture. Types: Dorsal and ventral spinocerebellar tracts. 3. Descending Tracts (Motor Pathways)
Transmits sensation from the upper limbs and trunk (upper body). Pathway: Receptor →right arrow Dorsal Root Ganglion →right arrow Dorsal Column →right arrow Medulla (Decussation) →right arrow →right arrow Sensory Cortex. B. Spinothalamic System (Anterolateral System) Function: Pain, temperature, and crude touch. | | Upper Motor Neuron (UMN) Lesion |
These tracts carry motor signals from the brain to lower motor neurons in the ventral horn, which then stimulate muscles. A. Pyramidal Tracts (Corticospinal Tracts)
Presenting clinical scenarios is essential for a high-quality PPT presentation, as it bridges theory with real-world medical practice. Descending Tracts (Motor Pathways)
Damage to the dorsal columns (e.g., in syphilis) leads to loss of proprioception. Key Takeaways for Your PPT Ascending = Sensory = Upwards Descending = Motor = Downwards
Medial portion, carries information from the lower limbs (below T6).
From receptor to the spinal cord (Dorsal Root Ganglion). 2nd Order: From the spinal cord/brainstem to the thalamus. 3rd Order: From the thalamus to the cerebral cortex. Tract Name Modality (Function) Decussation (Crossing) Dorsal Columns (Gracilis & Cuneatus) Fine touch, vibration, conscious proprioception Medulla Oblongata Lateral Spinothalamic Pain and temperature Spinal Cord (Anterior Commissure) Anterior Spinothalamic Crude touch and pressure Spinal Cord Spinocerebellar (Ant. & Post.) Unconscious proprioception for coordination Some cross twice, some remain uncrossed 2. Descending Tracts (Motor Pathways)
