Spinal Cord Injury (SCI) Flashcards
CNS = brain and spinal cord
- the brain controls how we think, learn, move, and feel
- the spinal cord carries messages back and forth between the brain and the nerves that run throughout the body
Upper motor neurons (UMN) vs lower motor neurons (LMN)
- upper neurons start in the brain, then comes down the spinal cord
- in the spinal cord, the upper motor neurons meet up with the lower motor neurons and then it goes to the muscles
Upper motor neurons (UMN)
- location = originate in the motor cortex of the brain and project down to the spinal cord
- function = responsible for conveying signals from the brain to the lower motor neurons, initiating and controlling the voluntary movements
- pathway = travel through the brain stem and spinal cord, synapsing with lower motor neurons in the anterior horn of the spinal cord
Lower motor neurons (LMN)
- location = located in the anterior horn of the spinal cord and brainstem, then project to the muscles
- function = directly innervate skeletal muscles and are responsible for muscle contraction
- pathway = receive signals from upper motor neurons and transmit these signals to the muscles, facilitating movement
Diagram (slide 5)
1.) motor nerve cells
2.) upper motor neuron
3.) midbrain
4.) pons
5.) medulla
6.) spinal cord
7.) lower motor neuron
- the nerve divides into many branches in the skeletal muscle
- each branch ends at motor plate of a single muscle fiber
Spinal nerves
- cervical plexus = C1-C5
- brachial plexus = C6-T1
- lumbosacral plexus = T12-S5
Cervical nerves
- C1-C8
- head and neck
- diaphragm
- deltoids and biceps
- wrist extenders
- triceps
- hand
Thoracic nerves
- T1-T12
- chest muscles
- abdominal muscles
Lumbar nerves
- L1-L5
- leg muscles
Sacral nerves
- S1-S5
- bowel and bladder
- sexual function
Causes of spinal cord injury
- falls (most common)
- motor vehicle accidents (most common)
- sports-related or recreation-related injuries
- violence-related injuries
- diseases
Falls
- about 31% of SCIs are caused by falls
Motor vehicle accidents (MVAs)
- MVAs are the most common cause linked to spinal cord injuries
- constitute over 37% of all SCIs
Sports-related or recreation-related injuries
- athletics activities account for 8% of SCIs, including diving in shallow water and impact sports
Violence-related injuries
- acts of violence caused 15% of all spinal cord injuries
- includes penetrating injuries from sharp objects such as knives or bullets
Diseases
- certain diseases or conditions can also lead to a spinal cord injury
- osteoporosis
- arthritis = lumbar spine pushes into each other, causing an injury
- cancer
- spine tumors
- inflammatory conditions
Incidence and prevalence
- 18,000 new SCIs per year
- 302,000 people with SCIs in the U.S.
- 79% of people with SCIs are male
- average age at time of injury is 43 years old
- 47% of injuries occur between the ages 16-30
- average of 11 days spent in ICU/acute care
- average of 31 days spent in rehabilitation
- depends on the severity of SCI = typically 6-8 weeks in ICU and 4-6 weeks in rehab, and then 2 weeks to stabilize and get moving
Classification of SCI (the basics)
- quadriplegia (tetraplegia)
- paraplegia
- complete injury
- incomplete injury
- zone of partial preservation
Quadriplegia (tetraplegia)
- any degree of paralysis of all 4 limbs and trunk musculature
- C1-C8 injuries
Paraplegia
- any degree of paralysis of the lower extremities with the involvement of the trunk and hips depending on the level of the lesion
- T1-T12
- L1-L5
- S1-S5
Complete injury
- absence of motor or sensory function of the spinal cord below the level of injury
- the spinal cord is totally severed (nothing is preserved)
- ex: C8 injury, C8 works, but everything below that does not work
Incomplete injury
- some spinal cord function may be partially or completely intact
- some level of preservation (depending on where the spinal cord is injured
- ex: the front, back, or central of the spinal cord is injured
- there is still some signals that can get through
Zone of partial preservation
- some segments below the neurological level of injury with preservation of motor or sensory findings
Complete spinal cord injury
- the spinal cord is transected (cut off)
- below the level of injury = all ascending and descending pathways are interrupted (total loss of motor and sensory function)
Clinical signs of complete spinal cord injury
- severe back pain or pressure
- complete loss of movement and sensation below the level of injury
- loss of bowel and bladder function
- possible impaired breathing
Upper motor neuron injury
- location = CNS
- structures involved in = cortex, brainstem, corticospinal tract, spinal cord
- disorders = stroke, TBI, SCI
- tone = increased: hypertonic, spasticity, rigidity
- reflexes = increased: hyperflexia
- involuntary movements = muscle spasm: flexor and extensors
- voluntary movements = impaired or absent: obligatory synergies, dyssenergic patterns
- muscle bulk = disuse atrophy: variable, widespread distribution