81 Questions
Which type of tone is velocity dependent?
Rigidity
What does a positive Babinski reflex involve?
Dorsiflexion of the big toes and fanning of toes
What type of gait is typical of unilateral upper motor neuron lesions?
Hemiplegic gait
Which condition involves degeneration of both upper and lower motor neurons?
Amyotrophic lateral sclerosis
Which type of lesion is characterized by weakness with increased reflexes and tone?
Upper motor neuron lesion
Which neurotransmitter is the most common excitatory postsynaptic potential (EPSP)?
Glutamate
Which part of the nervous system mainly conveys afferent sensory information in the spinal cord?
Dorsal root ganglia
What is the function of the corpus callosum?
Connects one hemisphere to an area in the opposite hemisphere
What is the main function of the tentorium cerebelli?
Separates the cerebellum from cerebrum
Which structure does the midbrain pass through?
Tentorial notch
Which nerve roots mediate arm abduction at the shoulders?
C5
What is the function of the S1 nerve root?
Mediates dorsiflexion at the ankle
What is the typical symptom of lower motor neuron (LMN) lesions?
Muscle weakness and hyporeflexia
How is muscle strength loss measured?
On a scale from 0 to 5
What causes fasciculations in muscles?
Denervation hypersensitivity
What is clonus in the context of deep tendon reflex scale?
Sustained clonus
What does flaccid paralysis indicate?
Decreased tone and hyporeflexia
How does foot drop affect gait?
Excessive flexion of the knee in swing
LMN lesions are restricted to which segment of the spinal cord?
What do muscle atrophy and weakness indicate in infants?
What does a reduced deep tendon reflex scale value indicate?
What is the potential space between the skull and the periosteal layer of dura called?
Epidural space
Which type of herniation involves the movement of brain tissue from one intracranial compartment to another?
Transtentorial herniation
What structure adheres to the surface of the brain and follows gyri and sulci like shrink wrap?
Pia mater
What is the common cause of injury for subdural hematoma?
High acceleration/deceleration trauma
Which segment of the spinal cord is mostly gray matter and gives rise to nerve plexuses for the arms and legs?
Lumbosacral enlargement
What is the main function of the cerebrospinal fluid (CSF)?
Protection and cushioning
Which part of the spinal cord has the thickest white matter?
Cervical level
What does transtentorial herniation involve?
Movement of brain tissue between intracranial compartments
What causes arachnoid granulations to bulge through the dura?
Adherence to inner surface of dura
What is responsible for making cerebrospinal fluid (CSF)?
Choroid plexus in ventricles
What is the primary cause of non-traumatic subarachnoid hematoma?
Rupture of an arterial aneurysm
Which tract controls movement of the extremities and produces characteristic deficits when lesions occur along its path?
Corticospinal tract
What is the term for the somatotopic representation of motor nuclei in the motor cortex?
Homunculus
Which tract primarily controls the distal muscles of hands and feet, terminates in cervical and lumbosacral enlargements, and controls muscles on the contralateral side?
Corticospinal tract
Which tract facilitates flexor muscle tone and inhibits extensor muscle tone, leading to decorticate posturing of the upper extremities when lesioned above its level?
Rubrospinal tract
What is the key symptom of injury or disease influencing the upper motor neuron in the motor cortex?
Muscle weakness
Which structure separates the thalamus into anterior and posterior limbs, housing the corticospinal tract in the posterior limb?
Internal capsule
Where do upper motor neurons (UMNs) from facial regions synapse with lower motor neurons (LMNs) in the pons?
Facial nuclei
Which type of lesion results in unilateral facial weakness affecting the ipsilateral facial nerve?
Corticobulbar tract lesion
"Bell's palsy," characterized by facial muscle weakness or paralysis, is caused by injury to which cranial nerve?
Cranial nerve 7 (CN VII)
"Decorticate posturing" of the upper extremities is typically seen with a lesion above the level of which structure?
Red nuclei
What happens when upper motor neuron lesions occur at the cortical level?
Increased muscle reflexes (hyperreflexia)
Which type of paralysis is characterized by increased muscle tension of both lower limbs, active and hyperactive tendon reflexes, positive pathological reflexes, and scissor gait?
Spastic paralysis
What is the main characteristic of upper motor neuron lesions?
Weakness with increased reflexes and tone
Which neurotransmitter is most commonly associated with excitatory postsynaptic potentials (EPSP) in the nervous system?
Glutamate
What is the primary function of the tentorium cerebelli in the brain?
Separates the cerebellum from the cerebrum
Which structure mainly carries afferent sensory information in the spinal cord?
Dorsal root ganglia
What type of fibers connect one hemisphere to an area in the opposite hemisphere of the brain?
Commissural fibers
What is the role of the corpus callosum in the brain?
It connects one hemisphere to an area in the opposite hemisphere
Which phenomenon is associated with increased tone spasticity at the end of range of motion?
Clasp-knife phenomenon
In which type of posture does the extension of the arm and leg on the opposite side of the lesion occur due to damage to the red nucleus in the midbrain?
Decerebrate posture
Which disease is characterized by unknown etiology, degeneration of UMN, and is progressive and non-fatal?
Primary lateral sclerosis (PLS)
What is the typical gait pattern associated with unilateral UMN lesions, where the leg is held stiffly and abducted with each swing forming a semicircle?
Hemiplegic gait
What is the primary function of the sacral nerves?
Innervate bowel, bladder, and sexual function
Which nerve roots mediate leg extension at the knee?
L4
What is the main symptom of lower motor neuron (LMN) lesions?
Fasciculations
How is muscle strength loss measured?
Scale from 0 being no movement to 5 being movement possible, full resistance
What happens when upper motor neuron lesions occur at the cortical level?
Decorticate posturing of the upper extremities
What does a reduced deep tendon reflex scale value indicate?
Hyporeflexia
How would foot drop affect gait?
Lack of ankle dorsiflexion in swing
What is clonus in the context of deep tendon reflex scale?
Sustained clonus
What causes fasciculations in muscles?
(LMN) lesions
What is the main reason for the slow development of symptoms in a subdural hematoma?
Gradual accumulation of venous blood
In which type of herniation does brain tissue move from one intracranial compartment to another?
Transtentorial herniation
What is the function of the arachnoid granulations?
Absorption of excess cerebrospinal fluid into the bloodstream
Which artery is commonly associated with the development of an epidural hematoma?
Middle meningeal artery
What is the primary cause of non-traumatic subarachnoid hematoma?
Rupture of an arterial aneurysm
Which spinal cord level has the thickest white matter?
Cervical spine
What is the main function of the corpus callosum?
Integration of sensory and motor signals
Which tract primarily controls the distal muscles of hands and feet and terminates in the cervical and lumbosacral enlargements?
Lateral corticospinal tract
What is the term for the somatotopic representation of motor nuclei in the motor cortex?
Homunculus
What causes facial muscle weakness or paralysis associated with Bell's palsy?
Injury to the corticobulbar tract
Where do upper motor neurons (UMNs) from facial regions synapse with lower motor neurons (LMNs) in the pons?
Facial nuclei
Which structure separates the thalamus into anterior and posterior limbs and houses the corticospinal tract in the posterior limb?
Internal capsule
What trait characterizes decorticate posturing of the upper extremities typically seen with a lesion above the level of the red nuclei?
Facilitated flexor muscle tone
Which type of paralysis is characterized by increased muscle tension of both lower limbs, active and hyperactive tendon reflexes, positive pathological reflexes, and scissor gait?
Spastic paralysis
What contributes to unilateral facial weakness affecting the ipsilateral facial nerve?
(UMN) lesion in motor cortex
Which tract facilitates flexor muscle tone and inhibits extensor muscle tone, leading to decorticate posturing of upper extremities when lesioned above its level?
Rubrospinal tract
Which pathway controls movement of the extremities and produces characteristic deficits when lesions occur along its path?
Corticospinal tract
What structure forms synapses on lower motor neurons (LMNs) in the central gray matter of the spinal cord and brainstem motor nuclei?
Corticobulbar tract
Study Notes
Neurology and Neuroanatomy
- Velocity-dependent tone is a type of tone that changes with the speed of movement.
Reflexes and Motor Systems
- A positive Babinski reflex involves fanning of the toes and flexion of the knee.
- Unilateral upper motor neuron lesions typically exhibit a spastic gait.
- ALS (Amyotrophic Lateral Sclerosis) involves degeneration of both upper and lower motor neurons.
- Weakness with increased reflexes and tone is characterized by an upper motor neuron lesion.
Neurotransmitters and Neurophysiology
- Glutamate is the most common excitatory neurotransmitter involved in excitatory postsynaptic potentials (EPSP).
Spinal Cord and Peripheral Nervous System
- The dorsal columns of the spinal cord primarily convey afferent sensory information.
- The corpus callosum is responsible for interhemispheric communication.
- The tentorium cerebelli separates the cerebrum from the cerebellum and provides support for the cerebrum.
Cranial Nerve and Lesions
- The midbrain passes through the tentorium cerebelli.
- The C5 and C6 nerve roots mediate arm abduction at the shoulders.
- The S1 nerve root is responsible for foot extension.
- Lower motor neuron (LMN) lesions typically exhibit flaccid paralysis.
Neurological Signs and Symptoms
- Muscle strength loss is measured using the Medical Research Council (MRC) scale.
- Fasciculations in muscles are caused by LMN lesions.
- Clonus is a series of rapid, rhythmic contractions in response to sudden stretching of a muscle.
- Flaccid paralysis indicates LMN lesions.
Neuroanatomy
- The subdural space is the potential space between the skull and the periosteal layer of dura.
- Transtentorial herniation involves the movement of brain tissue from one intracranial compartment to another.
- The pia mater is a layer of meninges that closely adheres to the surface of the brain and follows gyri and sulci.
- The common cause of injury for subdural hematoma is a blow to the head.
- The cervical and lumbosacral enlargements are segments of the spinal cord that give rise to nerve plexuses for the arms and legs.
Cerebrospinal Fluid and Ventricles
- The main function of cerebrospinal fluid (CSF) is to cushion the brain and spinal cord.
- The choroid plexus is responsible for making cerebrospinal fluid (CSF).
Movement and Motor Control
- The corticospinal tract is responsible for controlling the movement of the extremities.
- The lateral corticospinal tract primarily controls the distal muscles of hands and feet.
- The rubrospinal tract facilitates flexor muscle tone and inhibits extensor muscle tone.
Clinical Syndromes
- Upper motor neuron (UMN) lesions are characterized by increased muscle tone, hyperactive tendon reflexes, and positive pathological reflexes.
- The key symptom of UMN lesions is spasticity.
- Decorticate posturing is typically seen with lesions above the level of the red nucleus.
Neurological Disorders
- Amyotrophic Lateral Sclerosis (ALS) is characterized by unknown etiology, degeneration of UMN, and is progressive and non-fatal.
- The main characteristic of UMN lesions is increased muscle tone.
Other
- The sacral nerves are responsible for controlling the muscles of the lower limbs.
- The primary function of the arachnoid granulations is to absorb cerebrospinal fluid (CSF).
- Epidural hematoma is commonly associated with injury to the middle meningeal artery.
Test your knowledge of neurological innervation with this quiz. Identify the nerve roots responsible for various muscle movements and functions in the body.
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