Spinal cord Flashcards
- Nucleus: Substantia Gelatinosa (SG)
- Location
- Function
- Sends Fibers to:
- Substantia Gelatinosa (SG)
- Posterolateral tip of the dorsal horn at all spinal levels
- Pain/temperature pathway
- LSST
Nucleus: Nucleus Proprius (NP)
Location
Function
Sends Fibers to:
Nucleus Proprius (NP)
Mid-portion of the dorsal horn
Pain/temperature pathway
Fasciculus proprius
- Nucleus: Nucleus Dorsalis (Clarke’s column)
- Location
- Function
- Sends Fibers to:
- Nucleus Dorsalis (Clarke’s column)
- Base of the dorsal horn from C8-L2
- Unconscious proprioceptive pathway
- Dorsal spinocerebellar tract (DSCT)
- Nucleus: Visceral Afferent Nucleus
- Location
- Function
- Sends Fibers to
- Visceral Afferent Nucleus
- T1-L2 and S2-4
- Visceral sensory integration and reflex center
- Intermediolateral gray, ventral horn, and hypothalamus via the fasciculus proprius (RF)
- Nucleus: Intermediate Gray (IG)
- Location
- Function
- Sends Fibers to
- Intermediate Gray (IG)
- Between the dorsal and ventral horns at all spinal levels
- Sensorimotor integration center
- Ventral horn
LSTT
fast pain and temp
Fasciculus proprius
slow, poorly localized pain temp
Dorsal spinocerebellar tract (DSCT)
unconscious proprioception
T1-L2 and S2-4
Intermediolateral gray, ventral horn, and hypothalamus via the fasciculus proprius (RF)
- Nucleus: Medial Motor Cell Column (MMCC)
- Location
- Function
- Innervation
- Medial Motor Cell Column (MMCC)
- Medial part of ventral horn, all levels
- Axial musculature
- The ventrolateral area of the LMCC innervates proximal limb musculature. The dorsolateral area innervates distal limb musculature. The retrodorsolateral area innervates the intrinsic muscles of the hands and feet.
- Nucleus: Lateral Motor Cell Column (LMCC)
- Location
- Function
- Innervation
- Lateral Motor Cell Column (LMCC)
- Lateral part of ventral horn in the regions of the cervical and lumbosacral enlargements
- Muscles of the extremities
- The ventrolateral area of the LMCC innervates proximal limb musculature. The dorsolateral area innervates distal limb musculature. The retrodorsolateral area innervates the intrinsic muscles of the hands and feet.
- Nucleus: Phrenic Nucleus
- Location
- Innervation
4.
Phrenic Nucleus
C3-5; subdivision of the MMCC
Respiratory diaphragm
- Nucleus: Spinal Accessory Nucleus
- Location
- Innervation
- Spinal Accessory Nucleus
- C1-6, continuous with the nucleus ambiguus in the medulla
- Sternocleidomastoid Trapezius muscles
- Nucleus: Intermediolateral Nucleus
- Location
- Innervation
- Intermediolateral Nucleus
- Lateral horn from T1-L2
- Sends preganglionic sympathetic fibers to visceral structures
- Nucleus: Sacral Autonomic Nucleus
- Location
- Innervation
- Sacral Autonomic Nucleus
- Lateral horn from S2-4
- Sends preganglionic parasympathetic fibers to bowel and bladder
Rexed’s Laminae III-VI
III-VI: Nucleus proprius
Rexed’s Laminae II
II Substantia gelatinosa
Rexed’s Laminae VII
VII: Nucleus dorsalis, Intermediate gray
Rexed’s Laminae: IX
IX: LMCC, MMCC
Rexed’s Laminae
III-VI
Nucleus proprius
VII
Nucleus dorsalis, Intermediate gray
IX
LMCC, MMCC
Medial divison of the dorsal root
- carries highly myelinated fibers for 2pt tactile/proprioception/vibration
- ascends and descends in the posterior column
- descending fibers participate in proprioceptive reflexes
Lateral division of the dorsal root
- carries fast pain and temp, visceral sensations
- ascends 2 spinal segments in the dorsolateral fasiculus of lasseur before synapsing in the substantial gelatinosa, and then decussating and traveling in the lateral spinal thalamic PW
dorsolateral fasciculus
comprised of primary axons associated with spinal cord reflexes and pain and temperature pathways.
passive touch and pressure information
Short ascending fibers in the posterior columns are part of the ventral spinothalamic pathway for conveying passive touch and pressure information.
proprioceptive and 2-point tactile discrimination information
- Long ascending fibers in the posterior column form the fasciculus gracilis and fasciculus cuneatus, which convey proprioceptive and 2-point tactile discrimination information from the lower and upper extremities, respectively.
descends in the lateral funiculus
Lateral Corticospinal Tract (LCST)
In the spinal cord, the LCST descends in the lateral funiculus and terminates in the anterior horn and intermediate gray at all spinal levels, especially cervical segments. The corticospinal tracts mediate
their influences primarily through the intrinsic spinal reflex circuits.
courses anterior to the LCST
Rubrospinal Tract (RST)
In the spinal cord the RST courses anterior to the LCST, and is part of the cortico-rubro-spinal pathway, the major descending pathway of the extrapyramidal system.
ascends in the anterolateral portion of the spinal cord
Lateral Spinothalamic Tract (LSTT)
The LSTT ascends as a somatotopically-organized tract in the anterolateral portion of the spinal cord. It conveys pain and temperature information to the ventral posterior lateral (VPL) nucleus of the thalamus.
precise proprioceptive information from the inferior 1⁄2 of the body and lower extremities to the anterior vermis of the cerebellum.
Dorsal Spinocerebellar Tract (DSCT)
conveys unconscious, precise proprioceptive information from the inferior 1⁄2 of the body and lower extremities to the anterior vermis of the cerebellum.
unconscious, general proprioceptive information general nature from lumbosacral levels to the anterior vermis of the cerebellum.
Ventral Spinocerebellar Tract (VSCT)
conveys unconscious, general proprioceptive information general nature from lumbosacral levels to the anterior vermis of the cerebellum.
the principal descending pathway for autonomic responses
Lateral Reticulospinal Tract (LRST) The LRST is considered the principal descending pathway for autonomic responses. [See Horner’s Syndrome]
- autonomic (bowel and urinary bladder control)
- nonvolitional (staging of motor activity) functions
- Spinoreticular fibers in the fasiculus proprius
- convey “slow” and visceral pain sensations to the ascending reticular activating system (ARAS): part of the spino-reticulo-thalamic pathway.
- ARAS-input tested as part of the GCS
- best response to a painful stimulus.
- fasciculus proprius are associated with transmission of diffuse pain (indirect spino-reticulo-thalamic pathway), autonomic (bowel and urinary bladder control) and nonvolitional (staging of motor activity) functions.
Anterior White Commissure
is comprised of secondary axons from the substantia gelatinosa that decussate in the AWC and ascend as the Lateral Spinothalamic Tract. A lesion of the AWC results in bilateral loss of pain and temperature in the associated spinal dermatomes.
Anterior (Ventral) Motor Neurons
- The anterior horn has both alpha and gamma motor neurons.
- Alpha motor neurons have axons that course in the ventral rootlets/roots, spinal nerves and directly innervate striated muscle cells.
- They are called lower motor neurons (LMN) due to the fact that they are the final output motor neuron to the striated muscle cells.
- LMN deficits include atonia, areflexia, and flaccid paralysis.
- exerts bilateral control of axial and proximal limb musculature during postural movements.
- Unilateral lesions of this group
Anteromedial Descending Group (corticospinal, vestibulospinal, reticulospinal, tectospinal) exert bilateral control of axial and proximal limb musculature during postural movements.
- anterior corticospinal
- lateral and medial reticulospinal
- ateral and medial vestibulospinal
- tectospinal tracts
Unilateral lesions of this group have minimal effect upon axial musculature.
Anterior Corticospinal Tract (ACST) terminates on lower motor neurons and neuronal “pools” in the anterior
horns of cervical segments.
Lateral Vestibulospinal Tract (LVST) facilitates extensor (antigravity)
muscle tone.
Medial Vestibulospinal Tract (MVST) directly influences the alpha motor
neurons to the extensor neck muscles.
Medial Reticulospinal Tract (MRST) originates the medial pontine
reticular nuclei and terminates in the intermediate gray of all levels of the
spinal cord, and influences the gamma efferent loops.
Tectospinal Tract is a small tract that originates in the superior colliculus,
decussates in the midbrain, and descends in the spinal cord adjacent to the MVST.
It terminates in the intermediate gray of all cervical levels. The tectospinal tract mediates visually directed reflex movements
of the head through the neck musculature.
Anterior Corticospinal Tract (ACST) terminates on lower motor neurons and neuronal “pools” in the anterior
horns of cervical segments.
Lateral Vestibulospinal Tract (LVST) facilitates extensor (antigravity)
muscle tone.
Medial Vestibulospinal Tract (MVST) directly influences the alpha motor
neurons to the extensor neck muscles.
Medial Reticulospinal Tract (MRST) originates the medial pontine
reticular nuclei and terminates in the intermediate gray of all levels of the
spinal cord, and influences the gamma efferent loops.
Tectospinal Tract is a small tract that originates in the superior colliculus,
decussates in the midbrain, and descends in the spinal cord adjacent to the MVST.
It terminates in the intermediate gray of all cervical levels. The tectospinal tract mediates visually directed reflex movements
of the head through the neck musculature.
roughness, texture, form, and localization: what kind of sensations are these and which spinal pathway carries them?
- Passive touch comprises such sensory modalities as roughness, texture, form, and localization. Correct performance of certain contact activities, such as grabbing a door handle, is dependent upon this type of crude tactile discrimination.
- Passive touch is conveyed via the ventral spinothalamic pathway. Clinically, passive touch tends to persist even after lesions of the posterior columns.
2-point tactile discrimination; stereognosis (awareness of shape, size & texture); proprioception or kinesthesia (dynamic position sense); vibratory sensations; and weight perception
what kind of sensations are these and who conveys them to the brain?
- Active touch
- associated with the capacity for learning tactile discrimination.
- Active touch is conveyed by the posterior column/medial lemniscal system.
- The refined sensory modalities associated with active touch include: 2-point tactile discrimination; stereognosis (awareness of shape, size & texture); proprioception or kinesthesia (dynamic position sense); vibratory sensations; and weight perception.
- Active touch is conveyed by the posterior column/medial lemniscal system.
Lesions of the parietal
- may disturb our recognition of our own body parts (denial of body scheme)
- ability to spatially discriminate objects (agnosia or cortical astereognosis)
- ability to perform certain complex learned motor activities (apraxia).
ability to perform certain complex learned motor activities
apraxia
Lesions/damage to parietal lobe would effect this ability
ability to spatially discriminate objects
Lesions of the parietal lobe may disturb our recognition of our own body parts (denial of body scheme); our ability to spatially discriminate objects (agnosia or cortical stereognosis); or our ability to perform certain complex learned motor activities (apraxia).
recognition of our own body parts
Lesions of the parietal lobe may disturb our recognition of our own body parts (denial of body scheme); our ability to spatially discriminate objects (agnosia or cortical astereognosis); or our ability to perform certain complex learned motor activities (apraxia).
