SCI Flashcards
Spinal Cord Anatomy (White matter)
myelinated tracts in peripheral
Spinal Cord Anatomy (Gray matter)
neuronal cell bodies, glial cells, and located centrally
o Anterior horns: control somatic muscles
o Posterior horn: control sensation
Do afferent nerves transport messages “to” or “away” from the brain?
To the Brain
Do efferent nerves transports messages to or away from the brain?
Away from the Brain
What is the Somatic nervous system involved in?
transports voluntary motor and sensory
What is the automatic/visceral nervous system involved in?
messages for involuntary systems
o Sympathetic
o Parasympathetic
Upper Motor Neuron
Initiate in cerebral cortex and synapse in the anterior horn. Damage occurs within spinal cord
What does the Upper Motor Neuron do to muscle tone, reflexes, and spasticity?
o Increased muscle tone, reflexes, spasticity
Where does the Lower Motor Neuron initiate and exit
initiates in anterior horn and exit through spinal nerves. Damage anterior horn cell
What does the Lower Motor Neuron do to muscle tone, reflexes, and spasticity?
o Decreased muscle tone, reflexes, spasticity
Sensory and Motor Tracts (suffix or prefex)
- Beginning with “spino” = sensory tract
- Ends with “spinal” = motor tract
Spinal Tracts: Sensory
Ascending/afferent
Spino= sensory
Spinothalamic Tract
Dorsal/Posterior Column Tract
Spinocerebellar Tract
Spinothalamic Tract:
- Lateral spinothalamic tract: pain and temperature sensation
- Anterior spinothalamic tracts: crude touch and pressure sensation
- Injury results in: contralateral or ipsilateral loss of pain and temperature
Spinal Tracts: Motor
Descending/efferent = motor
Corticospinal: skeletal muscle with voluntary control
Subconscious tract: balance, muscle tone, UE position
- Vestibulospinal
- Tectospinal
- Reticulospinal
- Rubrospinal
What are the 4 Subconscious motor Spinal Tracts?
Vestibulospinal
Tectospinal
Retculospinal
Rubrospinal
Reticulospinal tract
Is a descending tract from reticular formation to the spinal cord. Part of the subconscious motor Tracts
* Controls proximal and axial muscles, gross movements such as gait, reaching and posture, no fine motor
* controls muscle tone in flexor muscle groups
* Damage results in decreased postural control
Rubrospinal tract
Regulation of flexion and extension tone of large muscles and fine motor.
❑From the red nucleus to the spinal cord
❑Works with the corticospinal tract to control fine motor movement of the hand
❑Damage results in impaired fine motor control, gross motor not effected
Vestibulospinal tract
Inner ear info to assess head position
❑From vestibular nuclei to anterior horn of spinal cord
❑Facilitates activity in all antigravity (extensor) muscles)
❑Results in ataxia and postural instability to the side of damage
Tectospinal tract
Orients the eyes and head in response to loud noise, sudden movement, brightness
❑Superior colliculi: visual info
❑Inferior colliculi: auditory info
Autonomic Nervous System Innervation
- Sympathetic nervous system:
o Located in T1-L2/3 and contain afferent/sensory nerves - Parasympathetic nervous system:
o Located in brainstem- cranial nerve 3,7,9,10
o Located in sacral spinal cord- S2-S4
Autonomic Nervous System Functions (Sympathetic nervous system function)
o Increase heart rate and blood pressure, piloerection, perspiration
o Blood flow to skeletal muscles and the lungs is enhanced
o Increases heart rate and the contractility of cardiac cells
o Provides vasodilation for the coronary vessels of the heart
o Constricts all the intestinal sphincters and the urinary sphincter
o Inhibits peristalsis and decreases motility
o Stimulates orgasm
Autonomic Nervous System Functions (Parasympathetic nervous system function:)
o Dilating blood vessels leading to the GI tract, increasing the blood flow and relaxes sphincters
o Bladder - contraction of smooth muscle of bladder wall; relaxes urethral sphincter - promotes voiding
o Dedicated cardiac branches of the vagus and thoracic spinal accessory nerves impart parasympathetic
control of the heart
o Stimulates erection and sexual arousal
Background of SCI
- Spinal cord injury is defined as “the occurrence of an acute
traumatic lesion of the neuronal elements in the spinal canal
resulting in temporary or permanent sensory deficit, motor deficit,
or bowel and/or bladder dysfunction” - Results in devastating lifestyle changes due to loss of mobility
- Common cause of SCI is motor vehicle collision and falls
- 47 % of cases reported are incomplete tetraplegia/quadriplegia
- Less than 1% experience complete return of neurological function
prior to hospital discharge
Significance of SCI (stats)
- 18,000 new cases per year in the United States
- Estimated 299,000 living with SCI in the United States
- Average age at onset of injury is 43 years
- Average acute hospital stay is 11 days
- Over 78% are males
- 48-52% annual household income at 1-5 years post injury is less than $25,000
Level of Injury
Quadriplegia/ tetraplegia: C1-C7
Paraplegia: T1-S5
Complications of SCI
- Pressure sores
- Respiratory complications
- Heterotopic ossification
- Osteoporosis
- Pain
- Decreased range of motion
- Gastrointestinal
- Urinary tract infections
- Thromboembolism
- Autonomic Dysreflexia
- Cardiovascular disease
C5 Muscle Innervation
Elbow flexion, supination, weak shoulder flexors
- Inherently weak shoulder girdle
- Lack of shoulder internal rotators and shoulder adductors significantly limits function
C5 Muscle Innervation (Partial Innervation)
o Biceps
o Supinator
o Clavicular head of Pectoralis
o Anterior, middle, posterior deltoid
o External rotators and rotator cuff
No innervation of major trunk muscles with exception of trapezius
C5 Muscle Innervation (Full Innervation)
Rhomboids
C6 Muscle Innervation
- Stability and power of shoulder joint
- Full innervation of deltoid, rotator cuff, biceps
- Teres Major and latissimus provide shoulder adduction
- Wrist Extensors
- Pronator Teres
- Weak Latissimus dorsi
- Teres major
- Shoulder internal rotators
- Subscapularis
C7 Muscle Innervation
- Triceps
- Wrist flexors
- Pronators
- Strengthened Serratus Anterior, Latissimus Dorsi, Pectoralis Major
C8 Muscle Innervation
- Active grip and release of hand
- Shoulder girdle and muscles that attach to trunk are fully innervated
L1 Muscle Innervation
- Partial innervation of:
o Quadratus Lumborum
o Iliopsoas
o Psoas major
L2 Muscle Innervation
- Partial innervation of hip flexors and adductors:
o Flexors:
❑Psoas Major (L1-L3)
❑Iliacus (L1-L3)
❑Sartorius (L2-L4)
o Adductors (L2-L4):
❑Obturator externus
❑Adductor longus
❑Adductor magnus, and brevis
❑Gracilis
L3 Muscle Innervation
- Partial innervation of knee extensors (L2-L4)
- Rectus femoris
L4 Muscle Innervation
Ankle dorsiflexors: Tibialis Anterior (L4-L5)
L5 Muscle Innervation
- Great toe ext/flex
o Extensor Hallicus (L5-S1)
o Flexor Hallicus (L5-S1) - Ankle eversion/inversion
o Peroneus Longus/Brevis (L5-S1), Tibialis Posterior (L4-L5) - Hip abductors (L4-S1)
o Gluteus medius
o Gluteus minimus
o Tensor fasciae latae
S1 Muscle Innervation
- Ankle Plantarflexors
o Gastroc/Solues (S1-S2) - Knee flexors (L5-S2)
o Hamstrings (semitendinosus, semimembranosus, biceps femoris)
Spinal Shock (Autonomic Dysfunction and Shock)
Due to trauma to the spinal cord
- Absent sensation
- Absent motor control
- Areflexia
- Loss of autonomic control