SCI part 1 Flashcards
What does the anterior horn of the gray matter contain?
efferent (motor) neurons
What does the posterior horn of gray matter contain
afferent (sensory) neurons
Sympathetic nervous system arises where?
thoracolumbar, T1-L2
What is the sympathetic nervous system responsible for?
Prepares body for flight or fight, emergency responses
Increases HR, BP
Constricts peripheral blood vessels and redistributes blood
Inhibits peristalsis
Where does the parasympathetic nervous system arise from?
craniosacral division, CN III, VII, IX, X, pelvic nerves
What is the parasympathetic nervous system responsible for?
Conserves and restores homeostasis
Slows HR and reduces BP
Increases peristalsis and glandular activity
What modulates the autonomic nervous system?
Brain Centers
Descending Autonomic System (hypothalamus and lower brainstem)
Cranial Nerves
What are autonomic plexus?
cardiac, pulmonary, celiac, hypogastric, pelvis
What are the mechanisms of SCI?
flexion
flexion-rotation
compression
hyperextension
What is the most common lumbar injury?
flexion
The most common cervical injury?
flexion-rotation
Spinal areas of greatest frequency of injury:
C5, C7, T12, L1
Non Traumatic Causes
Disc prolapse, vascular insult, infections
What does the lesion level indicate?
most distal uninvolved nerve root segment with normal function; muscles must have a grade of at lease a 3+/5 or fair+ function
Tetraplegia (quadriplegia):
injury occurs between C1 and C8 > involves all 4 extremities and trunk
Paraplegia
injury occurs between T1 and T2-L1, involves both lower extremities and trunk (varying levels)
Grade A ASIA Impairment Scale
Complete lack of motor and sensory function below the level of injury (including the anal area, S4 and S5)
Grade B ASIA Impairment Scale
Incomplete: sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5
Grade C ASIA Impairment Scale
Incomplete: motor function is preserved below the neurological level, and most key muscles below the neurological level have a muscle grade of less than 3
Grade D ASIA Impairment Scale
Incomplete: motor function is preserved below the neurological level, and most key muscles below the neurological level have a muscle grade of 3 or more
Grade E ASIA Impairment Scale
All neurologic function has returned.
Complete SCI:
Absence of sensory and motor function below lesion level
Incomplete SCI:
Involves partial preservation of sensory and motor functions below the lesion level
Common causes of SCI:
Transection
Compression
Infection
Degenerative Disorders
Transection
Complete severance of the cord
All sensory & motor information is interrupted at or below lesion level
Compression
Impingement of the cord
Symptoms depend on the severity of the injury
Non-traumatic SCI:
narrowing spinal canals
disc prolapse, vascular insult, TA
Traumatic SCI:
Most involve a single level or limited number of contiguous vertebrae
Result from forces that create violent motions of head or trunk
Most often areas of injury in traumatic cervical injury?
C5 and C7
Flexion, vertical loading, and extension accompanied by rotation or lateral flexion
Why is the thoracic area less likely to be injured from traumatic causes?
rib cage and higher stability as compared to cervical region
Most common site of injury in thoracic region:
T12-L1 junction
Mechanisms of Secondary Tissue Destruction
ischemia
edema
demyelination and destruction
What is spinal shock?
Temporary phenomenon that occurs after trauma to the spinal cord in which the cord ceases to function below the lesion
When does spinal shock usually resolve?
Usually resolves within 24 hours of the injury with the return of the anal and bulbocavernosus reflexes
What is affected with spinal shock?
Spinal reflexes, voluntary motor control, sensory function, and autonomic control are absent below the level of the lesion
5 Most Important Tracts to Clinically Evaluate
Lateral Costicospinal Dorsal Column Lateral Spinothalamic Spinocerebellar Vestibulospinal
Lateral Corticospinal Tracts
Voluntary motor control on the contralateral side
Dorsal Column
Conscious discriminative touch, pressure, vibration, and proprioception on the contralateral side
Lateral Spinothalamic Tracts
Conscious pain & temperature on the contralateral side
Spinocerebellar Tracts
Unconscious proprioception
Vestibulospinal Tracts
Facilitation of extensor tone (important to assess in neurologic injury)
