Spinal Cord Tracts Flashcards
Sulci and fissures
Longitudinal fissure
Lateral Sulci
Central Sulci (easier to see on lateral view)
Parieto-occiptal sulci
Frontal lobe regions
Primary motor cortex (Motor UMN corticospinal tracts)
Frontal eye fields (Eye movement)
Broca’s area (motor speech)
Parietal lobe regions
Primary Sensory cortex (post central gyrus): contralateral sensory input
Angular Gyrus
Dominant lesion: math, writing, Left from right, IDying fingers (Gerstmann Syndrome)
Nondominant lesion: Hemispatial neglect
Temporal Lobe regions
Superior Temporal gyrus: Primary auditory cortex, Wernicke’s area
Hippocampus
Amygdala
Fusiform Gyrus: Facial recognition, lesion=Prosopgnosia
Uncus: assoc with seizures, herniation= CNIII compression
Occipital Lobe regions
Primary visual cortex
Posterior limb of the internal capsule (ant 2/3rds)
motor fibers of the corticospinal tract
Posterior limb of the internal capsule (posterior 1/3)
Sensory fibers of the thalamocortical tract
Genu of the internal capsule
Motor fiberes of the corticobulbar tract
Spinal nerves exit below their respective vertebrae at what levels?
T1 through S5
Lumbar puncture passes through what layers
1- Skin 2- Facia and SC fat 3- Surpaspinous ligament 4- Interspinous ligament 5- Ligamentum flavum 6- Epidural space and fat (epidural anesthesia needle stops here) 7- Dura
Spinal tracts:
Dorsal Column responsible for
proprioception and vibration sensation
Spinal tracts:
Spinothalamic tracts responsible for
pain and temperature
Corticospinal tract responsible for
descending motor innveration
Dorsal column course
1st neuron through Dorsal root ganglion
Up through Dorsal column (fasciculus gracilis for lower extremity, fasciculus cuneatus upper extremity)
synapse in medulla on nucleus gracilis/fasciculus
2nd neuron decussates on contralateral medial lemniscus and travels up–> synapses on venteroposterolateral nucleus in thalamus
3rd neuron to ipsilateral somatosensory cortex
Spinal thalamic tract (anterolateral tract) course
1st neuron enters DRG
Synapses in ipsilateral gray matter posterior horn
2nd neuron decussates through anterior white commisure
ascends through contralateral white matter
synapses on VPL in thalamus
3rd neuron travels ipsilateral somatosensory cortex
Descending corticospinal tract course
1st neuron leaves primary motor cortex and travels through internal capsule and reaches medulla
Decussates at medullary pyramids
Descends through contralateral posterolateral white matter
synapses in anterior horn of gray matter
2nd neuron exits spinal cord through anterior root
synpases at NMJ
Upper motor neuron damage to the cortico spinal tract can occur at any point between primary motor cortex and the anterior horn gray matter. These signs include
Babinski reflex
spastic paralysis
clasp-knife spasticity
Increased tone and reflexes
Lower motor neuron of the corticospinal tract can occur ta any point from the anterior horn gray matter in the spinal cord to the NMJ. Sign of LMN damage include
Atrophy
Fasciculations
Decreased tone
Decreased Reflexes
What is the Romberg test?
Patient closes eyes to see if ataxia is cerebellar or dorsal column related
Need proprioception (DCML), visual aids (Cerebellum)to keep balance. Positive romberg means DCML issue
Bilateral symmetric loss of pain and temperature sensation in cape-like distribution seen with Chiari 1 malformation causes issues to the Spinothalamic tract just at the that level because
That’s where the 2nd order neurons are crossing over but doesn’t affect the other levels, can affect other tracts though. syringomyelia
