Spinal cord disorders Flashcards
Segments of the spinal cord
8 cervical
13 thoracic
7 lumbar
3 sacral
At least 2 caudal
Four functional regions of the spina cord
Cranial cervical (C1-C5)
Cervicothoracic (C6-T2)
Thoracolumbar (T3-L3)
Lumbosacral (L4-S3)
Lower motor neurons
Efferent neurons connecting the central nervous system to an effector organ
Cell bodies located within grey matter of cervicothoracic intumescence (C6-T2) for the thoracic limbs, and lumbosacral intumescence (L4-S3) for the pelvic limbs
UMN weakness
Refers to a lesion that interrupts the descending motor pathways from supraspinal neurons that converge on the LMN pool.
Clinical signs of UMN weakenss manifest as paresis and/or plegia with normal to increased spinal reflexes (hyperreflexia) and muscle hypertonia.
LMN weakness
Refers to a lesion of the ventral spinal cord grey matter and its axon coursing to the muscle through the spinal nerve roots and peripheral nerve.
Clinically manifests as paresis and/or plegia, decreased to absent spinal reflexes (hyporeflexia to areflexia), decreased muscle tone and muscle atrophy that is severe and rapid in onset.
C1-C5 lesions
Neck pain
Tetraparesis/plegia, ipsilateral hemiparesis/plegia, ataxia
- postural reaction deficits in all 4 limbs or in ipsilateral thoracic and pelvic limbs
- normal to increased spinal reflexes in all 4 limbs
- normal to increased tone in all 4 limbs
Ipsilateral Horner’s syndrome
Respiratory difficulty
Urinary retention
C6-T2 lesion
Neck pain
Tetraparesis/plegia, ipsilateral hemiparesis/plegia, ataxia
- postural reaction deficits in all 4 limbs or in ipsilateral thoracic and pelvic limbs
- decreased to absent reflexes in thoracic limbs, normal to increased reflexes in hind limbs
- decreased to absent tone in thoracic limbs, normal to increased tone in pelvic limbs
- muscle atrophy in thoracic limbs
Ipsilateral Horner’s syndrome
Respiratory difficulty
Urinary retention
T3-L3 lesions
Back pain
Paraparesis/plegia, ipsilateral monoparesis/plegia, ataxia
- postureal reaction deficits in both ot one pelvic limbs
- normal to increased spinal reflexes in pelvic limbs
- normal to increased tone in pelvic limbs
Schiff sherrington phenomenon possible in acute and severe lesion
Absent trunci reflex caudal to the level of the last in tact dermatome
Urinary retention (UMN bladder)
L4-S3 lesions
Back pain
Paraparesis/plegia, ipsilateral monoparesis/plegia, ataxia
- postural reaction deficits in both ot one pelvic limb
- decreased to absent spinal reflexes in hind limbs
- decreased to absent tone in pelvic limbs
- muscle atrophy in pelvic limbs
Urinary incontinence (LMN bladder)
Ataxia
Loss of proprioception, incoordination
Paresis
Reduced voluntary motor funtion
Paralysis
Absence of voluntary motor function
Schiff-sherrington posture
Lesion in thoracolumbar spinal cord segments alters the ascending inhibitory pathways from the border cells in the lumbar grey matter (L2-L4).
Axons of these cells ascend and terminate in the cervical intumescence.
Loss of this ascending inhibition to the thoracic limbs results in extension.
In spite of this increased in extensor tone the thoracic limbs are normal neurologically with respect to neuro function.
Vascular spinal diseases
Fibrocartilaginous embolic myelopathy
Infectious causes of spinal disease
Infectious meningo(encephalo)myelitis
Discospondylitis
Inflammatory causes of spinal disease
Steroid responsive meningitis
Meningo(encephalo)myelitis of unknown origin (MUO)
Idiopathic causes of spinal disease
(Sub)arachnoid diverticulum (SAD)
Traumatic causes of spinal disease
Vertebral fracture,
(sub)luxation
Spinal cord contusion
Haemorrhage
Traumatic disc herniation (Acute non-compressive neucleus pulposus extrusion - ANNPE)
Anomalous causes of spinal disease
Atlanto-axial instability
Vertebral and spinal cord anomalies
Syringohydromyelia
Neoplastic causes of spinal disease
Spinal tumours (extradural, extramedullary, intramedullary)
Nutritional causes of spinal disease
Hypervitaminosis A in cats
Degenerative causes of spinal disease
Inherited neurodegenerative diseases (storage diseases)
Intervertebral disc disease
Wobbler’s syndrome
Degenerative myelopathy
Lumbosacral stenosis
Spinal pain
Tissue damage or inflammation produces pain through stimulation of nociceptors
Most CNS parenchyma doesn’t have nociceptors - damage to grey and white matter is not painful
Meninges have a high density of nociceptors
What are the pain sensitive structures of the spine?
Periosteum of the vertebrae
Blood vessels
Meninges
Nerve roots
Intervertebral discs