11-25 Spinal Cord Flashcards
*The Spinal Cord and Vertebral column demonstrate ____ growth
*** How do Caudal spinal roots get placed into their intervertebral foramen?
****What is the [Caudal extent of Spinal Cord] in infants vs. Adults?
*Spinal Cord & Vertebral Columns demonstrate DIFFERENTIAL growth
**Relative rostral shift of the spinal cord with growth causes more caudal spinal roots to travel even more caudal until they eventually reach their intervertebral foramen
*****Caudal extent of Spina Cord in:
infants = L3
vs.
Adults = L1-L2 (but may vary from T12-L3 depending on height)
1) There are ___ pairs of Spinal Nerves. The __ dorsal root is MISSING 50% of the time
2) Where do these Spinal Nerves course through?
1) There are 31 pairs of Spinal Nerves. The C1 DORSAL ROOT is MISSING 50% of the time
2) Spinal Nerves course through INTERVERTEBRAL FORAMEN
Cervical (___-___) enlargement have corresponding nerve roots that form the ___ plexus and innervates ___ limbs.
vs.
Lumbosacral (___-___) enlargement have corresponding nerve roots tht form ___ plexus and innervates ___ limbs.
Cervical (C5-T1) enlargement have corresponding nerve roots that form the BRACHIAL plexus and innervates UPPER limbs.
VS.
LumbOsacral (L1, S2, S3) enlargement have correspondingly nerve roots tht form LUMBOSACRAL plexus and innervates LOWER limbs.
- Dura mater is a continuation of the ___ layer from ____ dura. How it is positioned? [2]
- —————————————————————————–
- —————————————————————————– - Describe the Arachnoid Meninges [2]
- Dura mater is a continuation of the MENINGEAL layer from CRANIAL dura.
- Forms sleeve around dorsal & ventral roots then fuses with epineurium of spinal nerves
- Dura mater is separated from vertebral periosteum by epidural space filled with [fatty connective tissue] & venous plexus
[Arachnoid Meninges]
A: thin membrane with delicate trabeculae attached to pia
B: Has subarachnoid space underneath it which CONTAINS CSF!
Pia Mater adheres to the _________. It fuses with the Dura mater at ___ and continues caudally as the ____ ______ which attaches to the ____ _____.
2) Denticulate ligaments & Filum terminale are types of Pia Mater. Describe Each.
Pia Mater adheres to the SPINAL CORD SURFACE. It fuses with Dura mater at S2–>and continues caudally as the COCCYGEAL LIGAMENT (which attaches to COCCYX POSTERIOR).
2)
Denticulate Ligament= 24 pairs of wing like pia extensions that attach to arachnoid and Dura and anchor the spinal cord
Filum Terminale= caudal Pia extension continuous with [conus medullaris] = tapered end of spinal cord
A: What is the Lumbar Cistern
B: Where is it located?
C: What does it contain?
- Where do MOST common vertebral injuries occur [2]
A: Lumbar Cistern= Subarachnoid Space CAUDAL TO CONUS MEDULLARIS
B: LC = Extends from [L1-L2] —> [S2-S3]
- MOST VERTEBRAL INJURIES
ºWhiplash/Head Impact/Car Accidents = [C1-C2] and [C4-C6]
•Industrial Accidents = [T2 - L2 ]
A: Dermatome
List Dermatome for the following:
1. Back of head
- Thumb & Index Finger
- Kneecap
- Nipples
- Umbilicus
- ## Lateral FootC: Most Dermatome regions Overlap each other. What are the 2 that don’t?
A: Cutaneous area innervated by a SINGLE DORSAL ROOT
B: A LOT of mixing & anastomosing of [Ventral Rami Spinal nerve trunks] leads to peripheral nerve sensory fields (which can include portions from several different dermatomes)
- Back of head = C2
- [Thumb & Index Finger]= C6
- Kneecap = L3
- Nipples = T4
- Umbilicus = T10
- ## Lateral Foot = S1MOST Dermatome regions Overlap EXCEPT: C2 and [Trigeminal/CN5B1-B3]
- [Pain, temperature, position sense, vibration from skin/body wall and pressure] come from the ___ component
- [Motor projections to Viscera, Glands & blood vessels] = ____ component
- Pain, sensations of FULLNESS/STRETCH come from the ____ component
*Alar Plates derive into the ____/____ root
Basal Plates derive into the ___/_____ root
- [Pain, temperature, position sense, vibration from skin/body wall and pressure] come from the GSA component
- [Motor projections to Viscera, Glands & blood vessels] = GVE component
- Pain, sensations of FULLNESS/STRETCH from viscera come from the GVA component
*Alar Plates Derive into SENSORY/DORSAL ROOT
{Afferent and Alar = Sensory}
*Basal Plates derive into MOTOR/VENTRAL Root
- Describe the White Matter of Spinal Cord vs. gray matter of spinal cord
- Describe these Regions:
A: [Dorsal Posterior Funiculus]
B: [Lateral Funiculus]
C: [Ventral ANTerior Funiculus]
D: [Dorsolateral Fasciculus /Zone of Lissauer]
- White= consist mostly of ascending & descending “tracts”
vs.
gray= made of many neuronal cell bodies embedded in a [neuropil]–>meshwork made of delicate neuronal & glial processes
—————————————————————————— - Fasiculus = Regions of Tracts / white mater
A: Dorsal F= Made of [fasciculus gracilis & fasciculus cuneatus] and is bordered by dorsal septum & [gray mater dorsal horn]
B: lateral F= Contains Asending & Descending Tracts
C: Ventral F= Also contains Ascending & Descending Tracts but found ANTerior
D: [Dorsolateral Fasciculus /Zone of Lissauer] = Found between apex of dorsal horn & edge of spinal cord
[Dorsal Posterior Horn] contains the [Substantia gelatinosa] and [Nucleus Proprius]
Describe the [Substantia gelatinosa] (3)
[Substantia gelatinosa]
ºIs “Pain Gate keeper” & filters sensory information by synapsing on dendrites in [Nucleus Proprius]
ºHomologous to spinal trigeminal nucleus
ºAxons ascend & descend 1 to 4 segments in [Dorsolateral Fasciculus /Zone of Lissauer]
1) What is [Clarke’s nucleus column] ?
2) Where is this found?
3) This Nucleus is homologous to what?
1) Receives muscle afferents that innervate muscle spindles and then projects ipsilaterally to cerebellum as the
[Dorsal Spinocerebellar Tract]
2) Found in Intermediate gray mater / and AKA [Nucleus dorsalis-medial] at C8-L2, L3
3) Homologous with [accessory cuneate nucleus of medulla]
1) Describe these 3 nuclei and List their vertebral location
A: [Lateral Horn-IML/Intermediolateral Nucleus]
B: [Sacral autonomic nucleus]
C: [IMM/IntermedioMEDIAL nucleus] (2)
2) Which mater are all of these nucleus located?
B: [Sacral autonomic nucleus] = laterally at [S2-S4] and origin of Cholinergic Preganglionic PARAsympathetic Efferents ((CPPE))
——————————————————————————
C: [IMM/InterMEDIOmedial nucleus] = located MEDIALLY AT ALL SPINAL CORD LEVELS and receives
-visceral afferents
-projects to [IML Nucleus] and gives rise to Sympathetic
——————————————————————————
ALL OF THESE ARE IN INTERMEDIATE GRAY MATER
[Ventral Anterior Horn] contains the [Lamina 8] and [Lamina 9]
Describe [Lamina 8]:
- location & involvement
- What type of input does it receive [4]
- What originates from this Lamina?
[Lamina 8] of [Ventral Anterior Horn]
- Located at base of ventral horn and involved in coordinating intersegmental reflexes
- receives inputs from descending tracts (i.e. vestibulospinal, [medial longitudinal fasciculus], reticulospinal & tectospinal tracts)
- Long ascending & descending axons which interconnect cervical & lumbar spinal cord levels ORIGINATE from [Lamina 8]
[Ventral Anterior Horn] contains the [Lamina 8] and [Lamina 9]
[Lamina 9] is the ___[smallest/Largest] at cervical & lumbosacral enlargements
- It contains what type of motor neurons and what do they innervate? [3]
- What 2 Nucleus does it house, where are they located and what do they innervate?
[Lamina 9] of [Ventral Anterior Horn] is the LARGEST at cervical & lumbosacral enlargements
- Contains 3 Neuron types :
º[LARGE Cholinergic (a-motor) neurons] AKA [lower motor neurons or final common pathway]–>innervate skeletal muscles
º[small inhibitory GABAergic glycinergic] neurons
Contains 2 Nucleus:
**Phrenic nucleus = located in medial part of [Ventral Anterior Horn] at C3-C5 –>innervates diaphragm
*[Spinal accessory nucleus= located in LATERAL part of [Ventral Anterior Horn] at {C1-C6 origin of spinal portion of [Accessory CN11] —>innervates SCM & Traps
Explain the [Stretch Reflex Arc] for the Patellar tendon [3]
1st: Tapping patellar tendon stretches quads—>causes Muscle spindle to “fire” action potential which travels to Dorsal Root ..then back out Ventral root to muscle
2nd: Ventral Root AP makes quads reflexively shorten/contract—>which makes [spindle nuclear bag] sag
3rd: Sagging of [spindle nuclear bag] finally causes gamma axons to fire and Re-Tense/reset the spindle bag
