Functional Neuroanatomy of the Spinal Cord Flashcards
(87 cards)
1
Q
SPINAL COLUMN
A
- Protect the spinal cord
- 7 cervical
- 12 Thoracic
- 5 Lumba
- 5 sacral fused
- 1 Coccygeal
To memorize faster:
P 7C 12T 5L 5S 1C
2
Q
SPINAL CORD
A
- 8 Cervical
- 12 Thoracic
- 5 Lumbar
- 5 Sacral
- 1 coccygeal
- It starts at C1, ends at L1-L2
3
Q
What is the relationship between the spinal cord and spinal vertebrae relationship?
A
- Not at the same level
- For radiologists/orthopedic surgeons, use vertebral level
- For neurologists and rehab, they use spinal cord level
- Difference is seen in the thoracic level
4
Q
State the Vertebral Level—> Spinal Cord Level
A
Vertebral Level ->Spinal Cord Level
T3 –> T6
T6 –> T9
T9 –> T12
T12–> L2-3
L2 –> None
5
Q
The terminal point is called?
A
Conus Medullaris
6
Q
- The spinal cord is covered by layers of what?
- What is the 3 layers?
A
- Meninges
- –> Pia Mater continue as the filum terminale
–> Dura Mater
–> Arachnoid Membrane
7
Q
It surrounds the spinal cord since it has pia mater and arachnoid membrane.
A
Cerebrospinal fluid
8
Q
It is the interval between the arachnoid membrane and the pia mater.
A
Subarachnoid Space
9
Q
- It is formed by spinal roots (left and right) that have not yet exited the spinal canal.
- It is also called the _____.
A
- Cauda Equina
- Horse tail
10
Q
- It is formed by ventral and dorsal roots.
- How many does this structure have in each segment?
A
- Spinal Roots
- It has 2 two each in each segment
11
Q
It has a dermatomal representation and bonds together with peripheral nerves.
A
Spinal roots
12
Q
This receives all afferent sensory impulses
A
Dorsal Root
13
Q
This sends out all efferent motor impulses.
A
Ventral Root
14
Q
Roots exit above corresponding vertebrae where C3 exits above C3
A
Cervical Area
15
Q
Roots exit below corresponding vertebrae where T1 exits below T1
A
Thoracic Area
16
Q
In a cross-section of the spinal cord, you will find this structure/liquid.
A
- Inner gray matter
- Outer white matter
- Dorsal Horn
- Ventral Horn
17
Q
It contains cell bodies for receiving sensation.
A
Dorsal Horn (Sensory Horn)
18
Q
It contains cell bodies for motor function
A
Ventral Horn (Motor Horn)
19
Q
This segment has a relatively large diameter and relatively large white matter. Posterior gray horns are enlarged, and anterior gray horns are well developed.
A
Cervical
20
Q
This segment has a small diameter r due to relatively small amounts of gray matter, except for the first thoracic segment. Anterior and posteriorly gray horns are relatively small.
A
Thoracic
21
Q
This segment has a nearly circular and large anterior and posterior gray horn. A small lateral gray horn is present in upper segments, with relatively less white matter than in cervical segments.
A
Lumbar
22
Q
This segment has relatively small but relatively large amounts of gray matter and relatively small amounts of white matter. Anterior and posterior gray horns are large and thick.
A
Sacral
23
Q
This segment resembles lower sacral spinal segments but is much smaller.
A
Coccygeal
24
Q
These are widest at C5-T1 and T12-L3 because they are for upper and lower extremity.
A
Gray Matter
25
Dorsal Horn is/are composed of?
1. Substancia Gelatinosa (Lamina 2)
2. Nucleus Proprius Dorsalis (Lamina 4)
3. Dorsal Nucleus of Clarke
26
It is part of the spinothalamic system, responsible for receiving pain sensations from the extremities.
Substancia Gelatinosa (Lamina 2)
27
It is part of the spinothalamic system, responsible for receiving temperatures and tactile sensations from the extremities.
Nucleus Proprius Dorsalis (Lamina 4)
28
1. Responsible for receiving unconscious proprioception from the extremities.
2. Where it is located?
1. Dorsal Nucleus of Clarke
2. At the base of the dorsal horn
29
It is composed of cell bodies and lower motor neurons and is innervated by the upper motor neurons or reflex arc.
Anterior Horn Cells of the Ventral Horn (Lamina7-9)
30
Give me the types of anterior horn cells.
1. Large Alpha Motor Neurons
2. Small Gamma Motor Neurons
31
It is for innervating regular skeletal muscles/extrafusal fibers.
Large Alpha Motor Neurons
32
It is for innervating muscle fibers at the ends of muscle spindles/intrafusal fibers.
Small Gamma Motor Neurons
33
Reflex arc is composed of:
1. Afferent Arm
2. Efferent Arm
34
Muscle spindle to dorsal horn.
Afferent Arm
35
Anterior horn cell to ventral root to peripheral nerve to muscle.
Efferent Arm
36
A neural pathway that controls a reflex.
Reflex Arc
37
Pathway of a Reflex Arc
Sensory Receptor --> Sensory Neurons --> Integrating Center--> Motor Neurons---> Effector
38
1. The origin of the sympathetic nervous system. Also, has a thoracolumbar outflow.
2. This are present in?
1. Lateral Horn (Nucleus Intermediolateralis)
2. T1-L3
39
It is composed of axons and fiber tracts and is found in dorsal, lateral and ventral.
White Matter
40
Dorsal Columns:
Fasciculus Gracilis
Fasciculus Cuneatus
41
Medial for LE sensation
Fasciculus Gracilis
42
Lateral for UE sensation
Fasciculus cuneatus
43
Receives pain and temperature impulse from the dorsal horn and sends them up to the thalamus and area 3,1,2 (primary somatosensory cortex)
Spinothalamic Tract
44
➢ Posterior columns
➢ Receives conscious proprioception, vibratory sense,
2 point discrimination and tactile sense
Dorsal Column Medial Leminiscus
45
➢ Receives unconscious proprioception from the
extremities and bring them up to the cerebellum
➢ Ventral tract – decussates
➢ Dorsal tract – uncrossed
Spinocerebellar Tract
46
Tract that decussates
Ventral Tract
47
Tract that uncrossed
Dorsal Tract
48
➢ Delivers motor impulses from the brain and
brainstem to the anterior horn cell
➢ Found in the lateral white matter
Corticospinal Tract
49
Dermatomal Levels
C3---> Below the Mandible
C5-T1--> Upper Extremity
T4--> Nipple Area
T6--> Costal Area
T10--> Umbilicus
L1--> Inguinal Ligament
50
Blood Supply
Anterior Spinal Artery
Posterior Spinal Artery
51
➢ Supplemented by intercostal and abdominal
arteries
➢ Dark areas less blood supply
Posterior Spinal Artery
52
➢ Bundles of axons that transmits data
➢ Data goes from extremities to brain (ascending)
➢ Data goes from brain to extremities (descending)
Tracts
53
➢ from below and go upward
➢ Sensory data
➢ Lateral and anterior spinothalamic tract
➢ Dorsal column medial lemniscus
➢ Dorsal and ventral spinocerebellar
➢ Spinoreticular system (pain pathways)
Ascending Tracts
54
Ascending Tracts is composed of 3 order neurons. What are those?
Neuron 1 (Template)
Neuron 2 (Template)
Neuron 3 (Template)
55
It begins where neuron 1 ends:
dorsal horn/nuclei-medulla
o Always decussates
o ends at VPL / Thalamus
Neuron 2 (Template)
56
It begins at the receptors in the
extremities
o Cell body – dorsal root ganglion
o Ends in the dorsal horn or nuclei of the
medulla
Neuron 1(Template)
57
It begins where neuron 2 ends
o VPL to area 3,1,2 (primary somatosensory
area)
o Enters the thalamocortical pathway
o Final common pathway
Neuron 3 (Template)
58
➢ Receives pain, temperature impulses from the
dorsal horn and sends them up to the thalamus and
area 3, 1, 2
➢ Anterior and lateral (goes up through the spinal
cord white mater)
Spinothalamic Tract
59
Begins at temperature (nucleus
proprius dorsalis) and pain (substantia gelantinosa)
receptors
o Axon: Peripheral nerve
o Cell body: DRG
o Enters dorsal horn of spinal cord
Nucleus 1:ST
60
Substantia gelantinosa / nucleus
proprius dorsalis to VPL
o Decussates at the spinal cord
o Passes through the tegmentum – brainstem
Nucleus 2:LST
61
Always from the VPL thorugh the
internal capsule and terminates in area 3, 1, 2
Neurons 3: LST
62
It brings pain, temperature, and tactile data to areas 3, 1, and 2 (primary sensory area)
Lateral Spinothalamic Tract
63
Starts from the receptors
o Axon: Peripheral nerve / fasiculus gracilis /
cuneatus
o Cell body: DRG
o Ends at the nuclei cuneatus / gracilismedulla
Neuron 1 in Dorsal Column Medial Leminiscus
64
Starts in the cuneatus (upper ex) /
Gracilis (LE) of the medulla and goes up to the
thalamus (VPL)
o Axons decussate at medulla
o Axons: Medial Leminiscus
Neuron 2 in Dorsal Column Medial Leminiscus
65
It begins at the thalamus (VPL)
o Passes through the internal capsule
o Ends at area 3, 1, 2
Neuron 3 in Dorsal Column Medial Leminiscus
66
It starts at the muscle spindle
o Axon: peripheral nerve
o Cell body: DRG
o Ends at Dorsal Nucleus of Clarke
Neuron 1 in Spinocerebellar Tract
67
From nucleus of Clarke to lateral white
mater
o Dorsal tract - uncrossed
o Ventral tract - decussates
Neuron 2 in Spinocerebellar Tract
68
The ventral tract to midbrain/brachium
conjunctivum
o Dorsal tract: to medulla – restiform body
Neuron 3 in Spinocerebellar Tract
69
➢ From above and goes below
➢ Motor data
➢ All are upper motor neurons
➢ Corticospinal
➢ Corticobulbar
➢ Rubrospina
➢ Reticulospinal
➢ Vestibulospinal
Descending Tract
70
Specific LMNs for each muscle
➢ Cell body: anterior horn cell
➢ Axon: peripheral nerve
➢ Commanded by UMN’s
Lower Motor Neuron
71
Must originate at the cortex (area 4)
Voluntary Muscle Contraction
72
tract for cranial nerves (muscles of the head:
facial expression and mastication)
Coticobulbar Tract
73
1. The origin of the corticospinal and corticobulbar tract
2. What area is it located?
1. Motor Homonculus
2. Area 4 (Primary Motor Area)
74
It starts from area 4
Corticospinal Tract
75
The majority (90%) of the
corticospinal fibers decussate at the lower
medulla
▪ A small group remains uncrossed
Decussation
76
All fibers end in the appropriate ventral horn to
synapse with the anterior horn cell
▪ Synapses with the lower motor
neuron
Termination of Corticospinal Tract
77
Lateral corticospinal tract synapses with anterior horn cell at specified level
▪ Anterior corticospinal tract
uncrossed
Synapse: UMN/LMN
78
o Decussate at the cranial nerve nuclei it will
innervate
o Ex. Hypoglossal nerve decussates at the
medulla
Corticobulbar Tract
79
It is needed for the maintenance of balance and posture
Involuntary Muscle Contraction
80
It works together with the rubrospinal tract
Reticulospinal Tract
81
Needed for reorienting the head
Vestibulospinal Tract
82
Gets data from spinocerebellum
Rubrospinal Tract
83
▪ From the red nucleus in the midbrain to
anterior horn cells
▪ For reorientation of the trunk
Rubrospinal Tract
84
▪ From vestibular nuclei to anterior
horn cells
Vestibulospinal Tract
85
▪ From the reticular formation (pons)
to anterior horn cells
Reticulospinal Tract
86
Clinical Manifestations
➢ Lower abdomen muscles
➢ Buttocks, legs, and feet
T10 Lesion
87
Clinical Manifestations
➢ Arms, hands, trunks, and legs
Left C4 Spinal Cord
