Spinal Nerves (all in pairs) 1. Total 2. Cervical 3. Thoracic 4. Lumbar 5. Sacral 6. Coccygeal

1. 31 2. 8 3. 12 4. 5 5. 5 6. 1

1. Alpha (primary) - innervate mm 2. Gamma - innervate spindle fibers, detect quick stretch and maintain appropriate length

Spinal Cord and PNS Flashcards by Kelsy Schoen

4 Functions of the Spinal Cord

Sensory from PNS to brain
Motor from brain to PNS
Reflexes
Modifying ascend/descending information

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Term: Connective tissue that connects end of cord to coccyx, places tension on the spinal cord in flexion

Filum terminale

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Term: L2-S5 nerve roots

Cauda equina

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Term: L1-L2 intervertebral space

End of Spinal Cord

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Spinal Nerves (all in pairs)

Total
Cervical
Thoracic
Lumbar
Sacral
Coccygeal

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Describe the location of spinal nerve in relation to vertebral bodies

C1-C7 exit ABOVE their corresponding vertebra

C8 exits BELOW C7 vertebra

All others exit BELOW their corresponding vertebra

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Describe why the cord is thicker or enlarged at the C&L-spine

Due to nerve plexuses - need to fit in all the MU for innervation of the extremities

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Defn: Dorsal root ganglia

Sensory neuron cell bodies

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Term: Nerve roots extening from end of spinal cord

Cauda Equina

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Location: Spinal nerves exit

Intervertebral space

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Location: Dorsal rootlets enter

Posterolateral sulcus (form dorsal root)

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Location: Ventral rootlets exit

Anterolateral sulcus (form ventral root)

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Structure: Formed by dorsal and ventral root

Spinal Nerve

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Type of Matter: in the spinal cord is arranged in horns

Gray matter

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Type of Matter: In the spinal cord is arranged in columns

White matter

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Term: Pathways to the brain

Tract cells

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2 Types of LMN

Alpha (primary) - innervate mm
Gamma - innervate spindle fibers, detect quick stretch and maintain appropriate length

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Type of Matter:

Sensory
Contains endings of sensory neurons
Interneurons
Cell bodies of tract cells

Gray matter - Dorsal horn

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Type of Matter:

From T1-L2
Cell bodies of preganglionic sympathetic neurons

Gray matter - Lateral horn

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Type of Matter:

Motor
Cell bodies of LMN

Gray matter - Ventral horn

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Type of Matter:

Sensory tracts
Discrimative touch
Conscious proprioception

White matter - Dorsal column

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Type of Matter:

Sensory tracts
Motor tracts

White matter - Lateral column

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Type of Matter:

Motor tracts
Postural regulation

White matter - Anterior column

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2 Regions within the Dorsal Column

Fasciculus Gracilis (LE)
Fasciculus Cuneatus (UE)

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Structure: - Indicates that you are in the C-spine - Separates Fasciculus Gracilis and Cuneatus

Posterior Intermediate Sulcus

5 Changes in the Spinal Cord as you DESCEND

1. Decrease in white matter - MORE sensory info as you move UP, motor info descends LESS pathways needed lower down 2. Overall size decreases 3. No posterior intermediate sulcus below T2 4. Lateral horn from T1-L2 5. Anterior horn larger at C&L plexuses

Term: All structures enclosed in bone, brain and spinal cord

CNS

Term: All neural structures distal to spinal nerves, sensory axons, motor/autonomic neurons, cranial nerves

PNS

Term: Carries sensory information to spinal cord

Afferent Axon

Term: Carries sensory infromation from spinal cord

Efferent Axon

Term: Group of mm innervated by a single spinal nerve

Myotome

Term: Dermis innervated by a single spinal nerve

Dermatome

Signs and Symptoms of CNS Injury

Motor/Sensory/Autonomic deficits will be in a myotomal/dermatomal distribution Will still receive some input/output from surrounding spinal levels

Signs and Symptoms of PNS Injury

Motor/sensory deficits will be in a peripheral nerve distribution

5 Periphery Deficit Signs

1. Paresis or paralysis 2. Sensory loss 3. Abnormal sensation 4. Muscle atrophy 5. Reduced/absent DTR

Type of Neuron: - Axons that descend from cerebral cortex or brain stem - 1st pathway - Completely within CNS

Upper Motor Neuron

Type of Neuron: - Cell body in brain stem or ventral horn - Axon leaves CNS - Synapses in PNS (on mm) - 2nd pathway

Lower Motor Neuron

4 Clinical Signs of UMN Injury

1. Paresis (not complete loss or paralysis - mutliple levels coming down) 2. Spasticity 3. Hypertonia 4. Hyperreflexia

5 UMN Diseases

1. Stroke 2. SCI 3. PD 4. TBI 5. MS

4 Clinical Signs of LMN Injury

1. Loss of reflexes or Hyporeflexia 2. Atrophy 3. Flaccid paralysis 4. Fibrillations/Fasciculations

4 LMN Diseases

1. Stroke 2. Polio 3. Peripheral nerve injury 4. Guillian Barre Syndrome

Disease that affects both UMN and LMN

Amyotrophic Lateral Sclerosis (ALS)

Term: 10 histologic regions of spinal gray matter

Rexed's Laminae

Function: Substantia Gelatinosa (LII)

Process pain information

Function: Nucleus Proprius (LIII&IV)

Processes conscious proprioception and discriminative touch

Function: Nucleus Dorsalis or Clark's Column (LVII)

Relays unconscious proprioceptive information to cerebellum

Rexed Laminae: Processes pain information

Substantia Gelatinosa (LII)

Rexed Laminae: Processes conscious proprioception and discriminative touch

Nucleus Proprius (LIII&IV)

Rexed Laminae: Relays unconscious proprioceptive infromation to cerebellum

Nucleus Dorsalis or Clark's Column (LVII)

Term: Involuntary sterotyped response to a sensory input

Reflex

Term: Reflex that does not involve interneurons

Stretch Reflex

2 parts of a Reflex Arc or Monosynaptic Reflex

1. Quick stretch stimulates Ia afferent in mm spindle 2. Ia afferent synapses in SC with alpha motor neuron located in dorsal horn

2 Ways the Reflex Arc is Modulated

1. Interneurons 2. UMN

Pathway Function: Dorsal Column Pathway (White)

F: Discriminative touch and conscious proprioception

2 Columns in White Matter that are Sensory Pathways

1. Dorsal Column 2. Lateral Column

Pathway Function and End Point: Spinothalamic Pathway (White)

F: Conscious pain and temperature EP: Thalamus

Pathway Function and End Point: Spinoreticular Pathway (White)

F: Alerting/Arousal; Unconscious Pain EP: Reticular Area

Pathway Function and End Point: Spinocerebellar Pathway (White)

F: Unconscious Proprioception EP: Cerebellum

3 Lateral Column Sensory Pathways (White)

1. Spinothalamic 2. Spinoreticular 3. Spinocerebellar

2 Columns in White Matter that are Motor Pathways

1. Anterior Column 2. Lateral Column

Pathway Function: Lateral Corticospinal Pathway (White)

Primary motor ouput: voluntary movement and fine motor control MOST CROSS

Pathway Function: Medial Corticospinal Pathway (White)

Same function as Lateral Corticospinal pathway HOWEVER only makes up 10% of total corticospinal pathways DO NOT CROSS

Pathway Function: Rubrospinal Pathway (White)

Gross motor movements under voluntary control

Location: Where rubrospinal pathway begins

Red Nucleus of Brainstem

Pathway Function: Reticulospinal Pathway (White)

Trunk movements and postural control

Pathway Function: Vestibulospinal Pathway (White)

Trunk movements and postural control

Pathway Function: Tectospinal Pathway (White)

Refelxive movement of head