Neurological Assessment Flashcards
Which CN are direct extensions from the brain
CNs I & II are white matter tracts that emerge as direct extensions from the brain
CN I
Olfactory nerve = sense of smell
CN II
Optic nerve = Sight
CN III
Oculomotor nerve = all eye muscles, except for superior oblique & external rectus muscle
CN IV
Trochlear nerve = superior oblique muscle of the eye
CN V
Trigeminal nerve = sensory to the face, sinuses and teeth; chewing muscles
CN VI
Abducens nerve = external rectus muscle of the eye
CN VII
Facial nerve = muscles of facial expression
CN VIII
Vestibulocochlear nerve = balance and hearing
CN IX
Glossopharyngeal nerve = sensory to the posterior tongue, tonsils, & pharynx; pharyngeal muscles
CN X
Vagus nerve = sensory & muscular inner action to the heart, lungs, bronchi, & digestive system; sensory in the trachea, larynx, pharynx, and external ear
CN XI
Accessory nerve = sternocleidomastoid & trapezius muscles
CN XII
Hypoglossal nerve = muscles of the tongue
How many pairs of spinal nerves are there?
- 31 pairs of spinal n.
- 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, & 1 coccygeal
What do peripheral nerves contain?
Both sensory (afferent) and motor (efferent) fibers
How does the Corticospinal tract control motor pathways
- Mediates voluntary movement and integrates skilled, complicated, or delicate movements by stimulating selected muscular actions and inhibiting others
- “Brain to spinal cord”
- Fibers decussate = cross in the medulla = right side of the brain controls movement of the left side of the body
- Higher motor pathways depend on intact lower motor neurons to affect movement
How does the Basal Ganglia system control motor pathways?
- Maintains normal muscle tone and to control body movements, especially gross automatic movements (walking)
What happens when the Basal ganglia is damaged?
- Damage causes rigidity, bradykinesia, involuntary movements, and/or disturbances in posture and gait
How does the Cerebellar system control motor pathways?
- Receives both sensory and motor input
- Coordinates motor activity, maintains equilibrium, and helps to control posture
What happens when the Cerebellar system is damaged?
- Damage can impair coordination, gait, equilibrium, decrease muscle tone, nystagmus or dysarthria
What is Corticobulbar motor pathway? What nerves does it directly innervate?
- Conducts impulses from the brain to the cranial nerves
- only 50% of these fibers decussate
- Directly innervates the nuclei of:
- V, VII, IX, and XII
- Contributes to the motor function of X
What happens when the Upper motor neurons of the corticospinal tract are damaged?
- increased muscle tone and HYPERreflexia b/c the lower motor neurons are disinhibited
What happens when the Lower motor neurons of the corticospinal tract are damaged?
- Decreased muscle tone and HYPOreflexia; atrophy and fasciculations
Corticospinal tract damage
- The corticospinal tracts have inhibitory effect on lower motor neurons
= weakness can be caused by damage to upper or lower motor neurons - Skilled, complicated or delicate movements are lost (not gross movements)
- When motor systems are damaged above their crossover in the medulla, motor impairment develops on the contralateral side
- Damage below the crossover = motor impairment on the ipsilateral side of the body
Sensory impulses give rise to what 3 things?
- Conscious sensation
- Location of body position in space
- Help regulate internal autonomic functions
Where do sensory impulses travel to in the spinal cord?
Dorsal (posterior) root ganglia in the spinal cord
What are the 2 pathways from the spinal cord to the sensory cortex of the brain?
- Spinothalamic tract = smaller sensory neurons with UNmyelinated or thinly myelinated axons
- Posterior columns = larger neurons with HEAVILY myelinated axons
What is the pathway of the spinothalamic tract
- Peripheral SMALL-fiber neurons arising in free nerve endings in the skin register:
- Pain, temperature, & crude touch
- these fibers pass into the posterior horn & synapse with 2nd order neurons
- 2nd order neurons then cross to the opposite side & pass upward into the thalamus
What is the pathway of the posterior column system (Dorsal column)
- Peripheral large-fiber projections transmit the sensation of:
- Vibration, Proprioception, Kinesthesia, Pressure, & Fine touch from the skin & joint
- Central projections travel upward in the posterior columns to 2nd order sensory neurons in the medulla on the SAME side of the body
- 2nd order neurons cross to the opposite side at the medullary level & continue to the thalamus
At the level of the thalamus what is perceived?
- The general quality of sensation (pain, cold, pleasant, unpleasant), but not fine distinction
For full perception of sensory where are impulses sent?
- To the sensory cortex of the brain
- Here stimuli are localized & higher-order discriminations are made
What level is the T4 dermatome?
Nipple level
What level is the T10 dermatome?
Umbilicus level
What level is the cardiac accelerator fiber located at?
T2
What dermatome level covers the inguinal area?
L4-L5
If you are performing a saddle block what dermatome/nerves are you blocking?
Sacral n.
If you are repairing an inguinal hernia what level do you want to block?
T10 - at least 3-4 dermatomes higher than the incision site
True or False the spinal reflexes occur due to the muscle stretching over structures relaying sensation from the PNS only.
False.
- The muscle stretch reflexes are relayed over structures of both the CNS and PNS
List the components of the reflex arc: (5)
- Sensory nerve fibers
- Spinal cord synapse
- Motor nerve fibers
- Neuromuscular junction
- Muscle fibers
Spinal nerves involved in the tricep reflex?
Cervical 6 & 7
Spinal nerves involved in the Brachioradialis (supinator) reflex?
Cervical 5 & 6
Spinal nerves involved in the Biceps reflex?
Cervical 5 & 6
Spinal nerves involved in the knee reflex?
Lumbar 2, 3, & 4
Spinal nerves involved in the ankle reflex?
Sacral 1
What are two guiding questions when assessing neuro health history?
- What is the localization of the responsible lesion (or lesions) in the nervous system?
- What is the underlying pathophysiology that explains the patient’s symptoms and neurologic findings?
What are the most common or concerning symptoms in the neuro assessment?
- Headache
- Dizziness or lightheadedness
- Weakness (generalized, proximal, or distal)
- Numbness or abnormal or absent sensation
- Fainting and blacking out (near-syncope & syncope)
- Seizures
- Tremors or involuntary movements