9 Spinal Cord Flashcards
(LO) ➢ Gross anatomy:
❖ meningeal layers and spaces of the spinal cord (e.g. epidural vs. subarachnoid)
❖ understand the difference between dorsal/ventral roots vs. dorsal/ventral horns
❖ differences in cells or cell parts present in gray matter vs. white matter
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(LO) ➢ Gray matter regions:
❖ Which lamina/nuclei are in dorsal (posterior) horn
❖ Which lamina/nuclei are in intermediate gray
❖ Which lamina/nuclei are in ventral (anterior) horn
❖ Nuclei names and lamina # where pain/temp fibers terminate & synapse
❖ Nuclei names and lamina # where crude touch fibers terminate & synapse
❖ Locations of pre-ganglionic sympathetic and parasympathetic neurons
❖ Location of the central canal
❖ At which specific rostral-caudal levels is there an enlargement of gray matter? Why?
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(LO) ➢ White matter:
❖ Locations of the 3 funiculi: anterior, lateral, posterior
❖ Know the sulci/fissures in a typical cross-section
❖ Understand the division of the posterior funiculus into fasciculus gracilis vs cuneatus
❖ Location and functional importance of the anterior white commissure
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(LO) ➢ Cross-sectional anatomy:
❖ Draw a typical spinal cord cross-section, including:
▪ Gray matter, white matter, and central canal
▪ Draw in borders of the 3 funiculi (approximately for lateral vs anterior)
▪ Draw bilateral locations of lateral corticospinal tracts
▪ Draw bilateral locations of anterior corticospinal tracts
▪ Draw bilateral locations of anterolateral (spinothalamic) tracts
▪ Draw or label the location of the anterior white commissure
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(LO) ➢ Reflex circuitry:
▪ Draw a typical cross-section and add in the circuitry for the patellar tendon reflex, mediating activation of the knee extensor response and inhibition of the flexor response.
▪ What cord level mediates this reflex?
▪ What are some other reflexes that are mediated at a single level of the spinal cord?
▪ How would the patellar reflex be affected if there was damage only to the ventral (anterior) horn? Only to the dorsal horn? Only to the corticospinal tracts? Only to the dorsal columns (posterior funiculus)? Only to the anterolateral tracts?
▪ What is clonus? How are stretch reflexes tested and what kind of stretch reflex response is normal vs. a clonus response? Does clonus happen when the ventral horn is damaged? When the corticospinal tracts are damaged?
▪ Describe the rating scale (from cases) used to rate reflexes, what rating is normal, which ratings are impaired reflexes, which ratings are exaggerated reflexes.
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(LO) ➢ White matter tracts: know the circuitry and functions of the three major systems and their tracts: corticospinal systems, dorsal column system, anterolateral (spinothalamic) system
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(LO) ❖ Corticospinal system (voluntary motor):
▪ Where are all upper motorneurons located?
▪ Where in the spinal cord are lower motorneurons located?
▪ How many times do the axons of upper motorneurons cross the midline?
▪ Which side of the body does the left precentral gyrus control?
▪ Which side of the body does the right precentral gyrus control?
▪ Describe the clinical rating scale for scoring motor strength (from cases).
▪ Does anterior horn damage produce lower motorneuron signs or upper motorneurons?
▪ Does damage to the lateral corticospinal tract produce lower motorneuron signs or upper motorneuron signs?
▪ Does damage to the anterior corticospinal tract produce lower motorneuron signs or upper motorneuron signs?
▪ If both the anterior horn and the lateral corticospinal tract on one side are damaged, are there lower motorneuron signs or upper motorneuron signs?
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(LO) ➢ Gross anatomy:
❖ meningeal layers and spaces of the spinal cord (e.g. epidural vs. subarachnoid)
❖ understand the difference between dorsal/ventral roots vs. dorsal/ventral horns
❖ differences in cells or cell parts present in gray matter vs. white matter
..
(LO) ❖ Dorsal Column System (fine/discriminative touch, proprioception):
▪ Where in the body (what tissue/organ) are receptors for fine/discriminative touch? For example, where are Merkel cells, Pacinian corpuscles, etc?
▪ Where in the body (what tissues) are receptors for proprioception?
▪ What is two-point discrimination and which sense does this test assess?
▪ What type of somatosensation is tested by the use of a tuning-fork?
▪ How many times does the entire dorsal column system cross the midline?
▪ Fine/discriminative touch and proprioceptive sensation from the left side of the body is represented in the postcentral gyrus on which side of the brain?
▪ Fine/discriminative touch and proprioceptive sensation from the right side of the body is represented in the postcentral gyrus on which side of the brain?
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(LO) ❖ Anterolateral (Spinothalamic) System (pain, temperature, crude touch):
▪ Which type of sensation is tested clinically by “pin-prick”?
▪ Once axon projections enter the anterolateral tracts and start ascending toward the brain, do they cross midline before reaching the postcentral gyrus?
▪ Pain, temperature, and crude touch sensation from the left side of the body is represented in the postcentral gyrus on which side of the brain?
▪ Pain, temperature, and crude touch sensation from the right side of the body is represented in the postcentral gyrus on which side of the brain?
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(LO) ➢ Review your drawing of the corticospinal system and use it to determine what deficits (weakness in upper extremity, trunk, lower extremity? on which side?) would occur if only this system was damaged at only one of the following points along the system: ❖ right precentral gyrus ❖ left lateral corticospinal tract at C4 ❖ left lateral corticospinal tract at L1 ❖ left anterior (ventral) horn at C5-C6 ❖ left anterior (ventral) root at C5-C6 ❖ left anterior (ventral) horn at L2-L4 ❖ left anterior (ventral) root at L2-L4
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(LO) ➢ Review your drawing of the anterolateral system and use it to determine what somatosensory deficits would occur if only this system was damaged at only one of the following points along the system:
❖ Peripheral nerve, e.g. axillary nerve, right side
❖ Dorsal (posterior) roots at C5 and C6, right side
❖ Dorsal (posterior) horn at C5 and C6, right side
❖ Anterolateral tract at T10, right side
❖ Fasciculus Cuneatus at C4, right side
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