Lecture 15 Functional Neuroanatomy Flashcards
▪ What is somatosensation? (BLANK)
▪ Various somatosensory modalities are described: (BLANK)
▪ Somatosensory modalities perceived are based on the type of (BLANK)
▪ What is somatosensation? all sensations that arise in skin, connective tissue, skeletal muscle, periosteum, and teeth
▪ Various somatosensory modalities are described: discriminative touch, vibratory sense, proprioception, pain, temperature
▪ Somatosensory modalities perceived are based on the type of somatosensory receptor(s) activated by a stimulus
▪ Function of somatic motor pathways is the generation of (BLANK)
▪ Intention to move arises in (BLANK) two neurons involved in pathway to skeletal muscle
Neuron 1: upper motor neuron
- definition: synapses on another neuron
- (BLANK) morphology
- cell body in (BLANK)
- synapses on (BLANK)
Neuron 2: lower motor neuron
- definition: synapses on skeletal muscle
- multipolar morphology
- cell body in (BLANK)
- projects via (BLANK) to produce movement
▪ Function of somatic motor pathways is the generation of volitional (purposeful) movements
▪ Intention to move arises in cerebral cortex; two neurons involved in pathway to skeletal muscle
Neuron 1: upper motor neuron
- definition: synapses on another neuron
- multipolar morphology
- cell body in cerebral cortex (primary motor cortex)
- synapses on lower motor neurons in spinal cord
Neuron 2: lower motor neuron
- definition: synapses on skeletal muscle
- multipolar morphology
- cell body in spinal cord
- projects via peripheral nerves to skeletal muscle to produce movement
(BLANK) refers to all types of cutaneous sensation (i.e., somatosensation)
- anesthesia: (BLANK)
-
(BLANK): spontaneous sensation that occurs in the absence of stimulation but that is not unpleasant (usually described as
“(BLANK); typically involves (BLANK) fibers -
(BLANK): an altered perception of an ordinary sensory stimulus that’s disagreeable or unpleasant; described
as (BLANK) –type pain; typically involves (BLANK) fibers - hyperesthesia: (BLANK) sensation for a given stimulus
- (BLANK): impairment of sensation short of anesthesia; diminished (BLANK)
- esthesia: refers to all types of cutaneous sensation (i.e., somatosensation)
- anesthesia: loss of sensation (numbness)
-
paresthesia: spontaneous sensation that occurs in the absence of stimulation but that is not unpleasant (usually described as
“pins and needles” or “tingling”); typically involves large fibers -
dysesthesia: an altered perception of an ordinary sensory stimulus that’s disagreeable or unpleasant; described
as burning or lancinating (electrical; shooting) –type pain; typically involves small fibers - hyperesthesia: exaggerated sensation for a given stimulus
- hypesthesia: impairment of sensation short of anesthesia; diminished sensitivity to stimulation
- algesia: (BLANK)
- analgesia: (BLANK) pain stimulus
- hyperalgesia (hyperpathia): (BLANK) sensation in response to a normally painful stimulus
- hypalgesia: (BLANK) and (BLANK) threshold to pain stimulus
- algesia: refers to a sense of pain
- analgesia: inability to perceive pain stimulus
- hyperalgesia (hyperpathia): exaggerated pain sensation in response to a normally painful stimulus
- hypalgesia: decreased sensitivity and raised threshold to pain stimulus
Testing primary somatosensation:
looking for asymmetry, sensory level
Assessment of pain (small fiber) pathways by BLANK: test comparisons and
boundaries, assess degree and quality , patients commonly describe stimulus as
BLANK; with lesions in pain pathways, patients often report BLANK
Assessment of pain (small fiber) pathways by pin prick: test comparisons and
boundaries, assess degree and quality , patients commonly describe stimulus as
sharp; with lesions in pain pathways, patients often report searing, burning, or electrical sensations
Assessment of discriminative touch (BLANK-fiber) pathways by BLANK, vibratory sense, proprioception: test comparisons and boundaries;
with lesions in discriminative touch pathways, patients commonly describe a
BLANK
Assessment of discriminative touch (large-fiber) pathways by two-point discrimination, vibratory sense, proprioception: test comparisons and boundaries;
with lesions in discriminative touch pathways, patients commonly describe a
tingling, numb sensation; a tight, bandlike sensation; or a sensation similar to gauze
on the fingers when palpating objects
Testing BLANK sensation: ability to perceive, recognize, and interpret BLANK; note that reliable testing requires BLANK to be intact bilaterally
1 2 and 3 what are they
Testing cortical sensation: ability to perceive, recognize, and interpret tactile objects: note that reliable testing requires primary
somatosensation to be intact bilaterally
Testing BLANK: patient stands with feet together , eyes closed. Look for instability (BLANK sign)
- BLANK all contribute to truncal stability;
closing the eyes removes BLANK input and the base of support is reduced bykeeping the feet together
- note: midline cerebellar lesion results in BLANK even
with BLANK
Testing proprioception: patient stands with feet together , eyes closed. Look for instability (Romberg sign)
- vision, proprioception, and vestibular sense all contribute to truncal stability;
closing the eyes removes visual input and the base of support is reduced bykeeping the feet together
- note: midline cerebellar lesion results in truncal instability even
with eyes open
proprioception typically follows BLANK rather than BLANK
- proprioception typically follows myotomes rather than dermatomes
- plegia: complete BLANK - loss of power of BLANK movement in a muscle through injury or disease of it or its nerve supply
- monoplegia: BLANK of one limb; term not applied to BLANK of isolated muscles or groups of muscles supplied by a single nerve or motor root
- BLANK: bilateral loss of lower limb function
- BLANK: loss of motor function down one side of the body; the most common form of paralysis
- BLANK (quadriplegia): loss of motor function in all four extremities
- plegia: complete paralysis - loss of power of voluntary movement in a muscle through injury or disease of it or its nerve supply
- monoplegia: paralysis of one limb; term not applied to paralysis of isolated muscles or groups of muscles supplied by a single nerve or motor root
- paraplegia: bilateral loss of lower limb function
- hemiplegia: loss of motor function down one side of the body; the most common form of paralysis
- tetraplegia (quadriplegia): loss of motor function in all four extremities
- paresis: partial or incomplete paralysis; weakness: degree of weakness determined by the extent of denervation
- palsy: paralysis or paresis; ambiguous term
- ataxia: inability to coordinate muscle activity during voluntary movements (cerebellar deficit)
- apraxia: loss of ability to execute previously learned activities in the absence of weakness, ataxia, sensory loss, or other motor derangement that would be adequate to explain the deficit
- paresis: partial or incomplete paralysis; weakness: degree of weakness determined by the extent of BLANK
- palsy: paralysis or paresis; ambiguous term
- ataxia: inability to coordinate muscle activity during BLANK movements (BLANK deficit)
- apraxia: loss of ability to execute previously BLANK, ataxia, sensory loss, or other motor derangement that would be adequate to explain the deficit
0 No contraction
1 Muscle flicker or trace contraction, but no movement
2 Active joint movement possible when effect of gravity eliminated
3 Active movement possible against gravity, but not against resistance
by examiner
4 Movement possible against some resistance by the examiner
5 Normal power
SCALE 0-4: Deep Tendon Reflexes
Biceps
BRAD
Triceps
Patellar
Achilies
Biceps C5/6
BRAD C6
Triceps C7
Patellar L4
Achilies S1
LMN signs: clinical signs that are observed when there is damage to a BLANK motor neuron
- BLANK paralysis of all muscles innervated by the lower motor neuron
- hypo__
- hypo__; plantar reflex if present, is flexor
- no movement possible but BLANK present
- BLANK atrophy (up to 70% decrease muscle volume within 3-4 months)
LMN signs: clinical signs that are observed when there is damage to a lower motor neuron
- flaccid paralysis of all muscles innervated by the lower motor neuron
- hypotonia
- hyporeflexia; plantar reflex if present, is flexor
- no movement possible but fasciculations present
- denervation atrophy (up to 70% decrease muscle volume within 3-4 months)
UMN signs: clinical signs that are observed when there is damage to an BLANK motor neuron;
typically related to BLANK tract (motor innervation of extremities) and corticonuclear tract (motor innervation of BLANK) damage
- BLANK (spastic paresis or paralysis)
- hyper__
- hyper__; plantar reflex is extensor (BLANK sign)
- motor weakness; movement possible, but with loss of BLANK
- muscles affected in BLANK, never BLANK muscles
- atrophy, if present, is BLANK (results from disuse, not BLANK)
UMN signs: clinical signs that are observed when there is damage to an upper motor neuron;
typically related to corticospinal tract (motor innervation of extremities) and corticonuclear tract (motor innervation of head and neck) damage
- spasticity (spastic paresis or paralysis)
- hypertonia
- hyperreflexia; plantar reflex is extensor (Babinski sign)
- motor weakness; movement possible, but with loss of dexterity
- muscles affected in groups, never individual muscles
- atrophy, if present, is slight (results from disuse, not denervation)
- spasticity
- increased BLANK to BLANK movement
- velocity-dependent; pathognomonic for BLANK damage
- manifests as BLANK response
- degree of spasticity not necessarily correlated with the
degree of muscle weakness
- spasticity
- increased resistance to passive movement
- velocity-dependent; pathognomonic for UMN damage
- manifests as clasp-knife response
- degree of spasticity not necessarily correlated with the
degree of muscle weakness
- hypertonicity
- muscles exhibit increased BLANK (feel BLANK on palpation),
but feel “BLANK” to patient - marked atrophy uncommon
- tone may be sufficient to aid in assisted standing
- hypertonicity
- muscles exhibit increased tone (feel firm on palpation),
but feel “weak” to patient - marked atrophy uncommon
- tone may be sufficient to aid in assisted standing
- weakness
- subtle BLANK disease can be assessed by looking for
BLANK drift; weak arm starts to BLANK
- weakness
- subtle UMN disease can be assessed by looking for
pronator drift; weak arm starts to drop and drift into
pronation
- loss of dexterity
- inability to produce BLANK, generally
of the BLANK - rapid movements will be BLANK and
BLANK
- loss of dexterity
- inability to produce fine movements, generally
of the digits - rapid movements will be slowed and
irregular
- hyperreflexia
- BLANK: repetitive oscillation between BLANK and BLANK at a BLANK joint (typically ankle) due to hyperactive flexor and extensor reflexes
- hyperreflexia
- clonus: repetitive oscillation between flexion and extension at a single joint (typically ankle) due to hyperactive flexor and extensor reflexes
Hoffman sign: enhanced BLANK relating to BLANK flexors; elicited by
loosely holding the BLANK finger and flicking the fingernail BLANK,
causing the finger to rebound slightly into BLANK; if the thumb flexes
and adducts in response, Hoffman’ s sign is present
Hoffman sign: enhanced reflexes relating to finger flexors; elicited by
loosely holding the middle finger and flicking the fingernail downward,
causing the finger to rebound slightly into extension; if the thumb flexes
and adducts in response, Hoffman’ s sign is present
Spastic hemiplegia
- UMN signs in left upper and lower extremity(BLANK to the side of the lesion), head and neck
- hypertonicity most marked in BLANK of BLANK and BLANK and BLANK of BLANK (anti-gravity muscles); arm assumes a flexed and pronated position; leg extended and adducted
- BLANK muscles usually spared
- spastic gait: stiff-legged, circumduction,
sometimes with scissoring of the legs and toe- walking (from increased tone in the calf muscles), decreased arm swing, unsteady, falling toward side of spasticity
Spastic hemiplegia
- UMN signs in left upper and lower extremity(contralateral to the side of the lesion), head and neck
- hypertonicity most marked in flexors of arm and digits and extensors of leg (anti-gravity muscles); arm assumes a flexed and pronated position; leg extended and adducted
- paraspinal muscles usually spared
- spastic gait: stiff-legged, circumduction,
sometimes with scissoring of the legs and toe- walking (from increased tone in the calf muscles), decreased arm swing, unsteady, falling toward side of spasticity
Neurological Testing_lumbosacral radiculopathy
Neurological Testing_lumbosacral radiculopathy
Neurological Testing_lumbosacral radiculopathy
C5
C6
C7
BLANK system
- the BLANK arises from the BLANK artery in the neck
- enters the skull and divides into the BLANK and BLANK BLANK artery
(terminal branches)
Internal carotid system
- the internal carotid arises from the common carotid artery in the neck
- enters the skull and divides into the anterior and middle cerebral artery
(terminal branches)
Internal carotid artery has two terminal branches:
- BLANK cerebral artery (supplies BLANK cerebral hemisphere)
- BLANK cerebral artery (supplies BLANK cerebral hemisphere)
Internal carotid artery has two terminal branches:
- anterior cerebral artery (supplies medial cerebral hemisphere)
- middle cerebral artery (supplies lateral cerebral hemisphere)
anterior choroidal – branch
of BLANK carotid; supplies
part of BLANK capsule
anterior choroidal – branch
of internal carotid; supplies
part of internal capsule
Branches of middle cerebral artery
- BLANK (supplies BLANK capsule)
Branches of middle cerebral artery
- lenticulostriate (supplies internal capsule)
Vertebral-basilar system
- vertebral arteries arise from the BLANK a. and ascend in the neck via the BLANK foramina of BLANK vertebrae
- enter the skull through the foramen BLANK, ascend on the BLANK aspect of the BLANK
- ## at the junction of the medulla and pons, the right and left vertebral arteries merge to form the BLANK artery
- at the junction of the pons and midbrain, the BLANK artery divides into the right and left BLANK cerebral arteries
Vertebral-basilar system
- vertebral arteries arise from the subclavian a. and ascend in the neck via the transverse foramina of cervical vertebrae
- enter the skull through the foramen magnum, ascend on the anterior aspect of the medulla
- ## at the junction of the medulla and pons, the right and left vertebral arteries merge to form the basilar artery
- at the junction of the pons and midbrain, the basilar artery divides into the right and left posterior cerebral arteries
Clinical connection:
vertebral artery
dissection - vertebral
arteries vulnerable to
injury; BLANK
and BLANK of head
results in BLANK and
BLANK of blood flow
Clinical connection:
vertebral artery
dissection - vertebral
arteries vulnerable to
injury; hyperextension
and rotation of head
results in torsion and
restriction of blood flow
Branches of vertebral artery
- posterior inferior cerebellar artery (PICA); supplies BLANK and BLANK
- posterior spinal artery (75% of cases br . of PICA; 25% of cases br . of vertebral); supplies
BLANK and BLANK
- anterior spinal artery; supplies BLANK and BLANK
Branches of vertebral artery
- posterior inferior cerebellar artery (PICA); supplies medulla and cerebellum
- posterior spinal artery (75% of cases br . of PICA; 25% of cases br . of vertebral); supplies
medulla and spinal cord
- anterior spinal artery; supplies medulla and spinal cord
Branches of posterior cerebral artery
- quadrigeminal (supplies lateral BLANK)
- thalamoperforating (supplies anterior BLANK)
- thalamogeniculate (supplies posterior BLANK)
Branches of posterior cerebral artery
- quadrigeminal (supplies lateral midbrain)
- thalamoperforating (supplies anterior thalamus)
- thalamogeniculate (supplies posterior thalamus)
Circle of Willis
Anastomosis of anterior and posterior circulations
- anterior communicating artery connects the right and left anterior cerebral arteries of the anterior circulation
- posterior communicating artery connects middle cerebral artery (or internal carotid) of anterior circulation to posterior cerebral artery of
posterior circulation
