1. Spinal Cord Function After Injury spinal cord structure in relation to vertebrae types of lesions fibre tracts in spinal cord sensory loss motor loss reflexes and spinal shock neuropathic pain

2. Orientation of spinal cord and spinal roots with respect to vertebrae Posterior

3. Collapse of disc space Disc prolapse Slippage of vertebra over disc

4. Collapsed vertebra in patient with severe osteoporosis

5. Arrows indicate S3- S4 disc prolapse Arrow indicates L4-L5 disc prolapse

6. Arrow indicates compression fracture at C5 Arrow indicates fracture- dislocation at C6/C7

7. Head and neck Diaphragm Deltiods, Biceps Wrist extenders Triceps Hand Chest muscles (T1-T7) Abdominal muscles (T7-T12) Leg muscles Bowel, bladder Sexual function

8. Paralysis of the lower half of the body is called paraplegia. Paralysis of both arms and legs is called quadriplegia (or tetraplegia).

9. Dorsal root ganglion Posterior Anterior Dorsal columns Cuneate funiculus Gracile funiculus Leg, Lower trunk Upper trunk, arm, neck, head Touch, vibration, pressure, Proprioception A α, Aβ Ventrolateral spinothalamic Pain, temperature, crude touch A δ, C Sensory fiber tracts

10. A α motor neuron Motor fiber tracts Posterior Anterior Lateral corticospinal Medial corticospinal Anterior horn cells anterior horn cells for limbs anterior horn cells for trunk

11. dorsal and ventral horns motor pain, temperature vibration, proprioception, touch Dorsal columns Ventrolateral spinothalamic Lateral Corticospinal, Anterior horn cells

12. lower limbs upper limbs medulla Aα, Aβ (touch, vib,propriocep) Aδ, C (pain, temp.) Aα motor

13. Examples The diagrams that follow indicate the motor and sensory loss as a consequence of one of the following lesions. Identify the lesion in each case and indicate on the spinal cord and spinal cord section the site, level and side of the lesion. Lesions: Anterior cord syndrome Posterior cord syndrome Central cord syndrome Transverse cord Hemicord (Brown-Sequard)

14. Central cord syndrome (small lesion) – cape distribution Eg. Spinal cord contusion (bruise causing bleeding in spinal column), spinal cord tumors Anterior cord syndrome Eg. Trauma, multiple sclerosis, anterior spinal artery infarct cervical T8/T9 Damage to spinothalamic fibers as cross anterior commissure

15. C D E Transverse cord lesion Eg. Trauma, tumors, multiple sclerosis (demyelination) T8/T9 Hemicord lesion Brown-Sequard Eg. Penetrating injuries, lateral compression from tumors, multiple sclerosis T8/T9 Posterior cord Syndrome Eg. Trauma, extrinsic compression from posterior tumors, multiple sclerosis T8/T9

16. Signs and symptoms of UMN versus LMN lesions UMN lesionLMN lesion YesWeaknessYes No (yes, disuse) AtrophyYes NoFasciculationsYes Increased*ReflexesDecreased Increased*Muscle toneDecreased *except decreased during spinal shock

17. Spinal Shock Initially hyporeflexia (spinal shock) (24hrs up to ~2months) Loss of descending excitation (bleeding, oedema, inflammation, cell hypoxia, cell death, demyelination) Followed by return of reflexes Denervation hypersensitivity (increased neurotransmitter release, increased responsiveness to neurotransmitter) Followed by hyperreflexia Axonal and soma regrowth (neural plasticity) with denervation hypersensitivty

18. Neuropathic pain Aδ, C Descending inhibition Inhibitory interneuron + Serotonin NA - Enkephalin Opioids SCI → Wind-up Denervation hypersensitivity, increased neurotansmitter release, increased responsiveness to neurotransmitter, neural plasticity + Glutamate Treat early to prevent wind-up (hyperalgesia) Drugs: opioids, antiepileptics (block Na + channels), Tricyclic antidepressants (serotonin and NA reuptake inhibitors) Surgery: nerve root ablation