Ch. 13: Spinal Region Flashcards
The spinal cord extends from the _____________ down to _______________.
The spinal cord extends from the Foramen Magnum down to L1 or L2 level.
Cauda Equnia
Collection of nerve roots and spinal nerves that are outside the spinal cord but inside the spinal ring
What are the two thickest parts of the spinal cord?
Cervical and Lumbar
(The MOST gray mater → Contain cell bodies for all the movement of our arms & legs)
What root controls motor?
Ventral root
What root controls sensory?
Dorsal root & dorsal root ganglion
How many spinal nerves are there?
31 spinal nerves
(31 spinal segments)
What are the segments of the Spinal Cord made up of?
Areas of spinal cord associated with axons in a single spinal nerve
Where are all white matter columns the biggest in the spinal cord?
Cervical cord
(lateral corticospinal tract is biggest here)
Where are all white matter columns the smallest in the spinal cord?
sacral cord
Spinal nerve
All motor and sensory axons of a single spinal segment
Where do all spinal nerves exit from C7 & rostral?
ABOVE corresponding vertebra
Where do all spinal nerves exit from T1 & caudal?
BELOW corresponding vertebra
Where does C8 exit the spinal cord?
Between C7 & T1
How many Rami are there and what are they called?
- Dorsal primary rami
- Ventral primary rami
- White communicating rami
- Gray communicating rami
Where is the lateral motor division located in the spinal cord?
The lateral spinal cord
In the white matter of the spinal cord, where is the somatotopic organization?
Somatotopic organization of major sensory and motor tracts
In the Gray matter of the spinal cord, what does each horn do?
- Dorsal horn: senroy
- Lateral horn: autonomic
- Ventral horn: LMN cell bodies
What are Rexed’s Laminae?
Histologically and functionally distinct areas of gray matter
(the right half of the attached pictures with the Roman Numerals)
What are the functiosn of the spinal cord?
- Integrate information (synapse = opportunity for processing and modification of signals).
- Transmit information (“vertically” and “horizontally”)
- Info to and from the brain
How does afferent input and descending commands affect movement?
- Reflexes (afferent input) can modify motor plan
- Motor plan (descending commands) can modify reflexes
What are central pattern generators?
Pre-existing group of neurons → make walking more automatic
What is the Phasic Stretch Reflex?
- Quick stretch of MUSCLE SPINDLE
- Synapse is in the spinal cord
What is the Withdraw Reflex?
Multisynaptic, mutliple muscle withdraw
What is the Crossed Extension Reflex?
- More complex - Multisynaptic, multiple muscle withdrawal
- Leg in pain FLEXES (blue), other EXTENDS (red)
What is Reciprocal Inhibition?
- Agonist facilitated → Antagonists inhibited
- (ex: hamstrings inhibited when quads facilitated).
- Occurs both through voluntary movement (thought) and reflex.
- Can be suppressed (ex: to allow voluntary cocontraction).
What type of muscle and control level are in the bladder?
- Smooth muscle
- Autonomic control
What are the different control centers of the bladder?
- Frontal control center
- “Modulatory”
- Pontine control center
- “Control”
- Spinal cord centers (lumber & sacral)
- “Efferent” (pre-ganglion)
- “Afferent” (bladder wall)
What is the sympathetic systems effect on the baldder?
What spinal levels?
- T11-L2
- Prevents emptying
- Relaxes bladder wall and contracts internal sphincter
What is the parasympathetic systems effect on the baldder?
What spinal levels?
- S2-S4
- System of Elimination
- Contracts bladder wall and relaxes internal sphincter
What is the autonomic systems effect on the baldder?
What spinal levels?
- S2-S4
- Voluntarily opens external sppincter
- Consciously tell you bladder “I can’t go here, I have to hold it”
What facilitates voiding reflex?
Stretch of bladder
(this can get our of wack with neuro impairments)
What are the systems and their spinal levels that control the bladder?
- T11-L2: Sympathetic - fill
- S2-S4: Parasympathetic - empty
- S2-S4: Somatic - conscious opening of external sphincter
What systems consciously open the external sphinter and allow voiding reflex to occur?
Descending somatic and autonomic axons
What happens in the higher centers when it is “OK” to go?
- Higher centers
- Allow emptying reflex
- Relax external sphincters
What happens in the higher centers when it is “Not OK” to go?
- Higher centers
- Try to stop emptying reflex
- Contract external sphincter
What happens to the bladder when the lines of communication get cut?
It reflexes on its own.
(Picture is normal neural control of bladder)
What are the SNS and PNS effects on external genitalia?
- Erection = parasympathetic nerves.
- Ejaculation = sympathetic and pudendal nerves.
What is damaged in a Segmental Lesion?
Damage to one spinal nerve
What is the pattern of loss with a Segmental Lesion?
- Segmental Pattern: at level of lesion ONLY
- Dermatomal Sensory loss: no sensory can get it
- Myotomal Motor loss: no motor can get out
- Autonomic loss in one segment
What are the signs and symptoms with a Segmental Lesion?
- Weakness of many muscles
- Hyporeflexia (LMN) - reflexes will be weaker or gone
- Hypotonia (LMN)
*Vertical tracts can easily go up and down passed lesion
What is damaged in a Vertical Tract Lesion?
- Damage completely across spinal cord
What is the pattern of loss with a Vertical Tract Lesion?
- Sensory loss: ALL segments below lesion
- Motor loss: ALL segments below lesion
- Autonomic loss: ALL segmetns below lesion
What are the signs and symptoms with a Vertical Tract Lesion?
- Paralysis (UMN)
- Hyperreflexia (UMN)
What are the signs and symptoms of segmental + vertical tract dysfunction?
- Stereotype of complete spinal cord injury
- Loss of segmental function AT level of injury
- Loss of verticl tract functions at ALL levels BELOW level of injury
How do you differentiate between a peripheral region legion and a spinal region lesion?
- Peripheral
- Sensory & motor loss in peripheral nerve pattern
- No vertical tract signs
- Spinal
- Senation loss: dermatome
- Motor loss: myotome
- Dec/loss phasic stretch reflex
- Dec/loss of sensation or control below level of lesion
What is Anterior Cord Syndrome?
- Front 2/3 of spinal cord is damaged
- MOI: Blockage in ant spinal artery
- NO: voluntary function below level of the injury; pain & temp gone
- YES: light touch and proprioception
What is Central Cord Syndrome?
- Center of spinal cord fills up like a balloon
- NO: pain & temp where central canal has swelled up
- No damage to columns or horns - damage to pain message where it crosses in the spinal cord
- Prox & core muscles will weeken at whatever levels there is swelling
- COMMON in the cervical spinal cord
What is Brown-Sequard Syndrome?
- Half Injured
- Ipsilateral loss
- Dorsal Column: discrinative touch
- Corticospinal: motor function
- Contralateral loss
- Anterolateral column: pain & temp
- Ipsilateral loss
What is Cauda Equina Syndrome?
- Injury to peripheral sensory neurons & LMN’s
- Pain, all sensations impaired, muscle weakness, altered bladder and bowel control
(Spinal nerves outside spinal cord but inside bony spinal column)
What is a Spastic Bladder and what causes it to happen?
- No autonomic control of reflex emptying loop
- Hyperreflexic bladder - reflex loop intact, can not consciously control
- Empties with less stimulus and exaggerated response
- Lesions ABOVE sacral cord - similar to UMN lesion
What is a Flaccid Bladder and what causes it to happen?
- Bladder fills w/ no reflex to empty it
- ex: Cauda Equina
- Lesions OF sacral segements - similar to LMN lesion
What is spinal shock?
- Inital loss or impairment of:
- Spinal level reflexes
- Autonomic reflexes
- Wheres off in a couple weeks/months
What is Tetraplegia/Quadriplegia?
4 limbs effected
(both arms, both legs)
What is Paraplegia?
2 limbs effected
(typically, 2 legs)
What is the difference between Complete vs. Incomplete SCI?
- Complete: All vertical tracts cut
-
Incomplete: Spares lowest sacral segments (S3-S5)
- preserves sensory &/or motor function here
What is the Neurological Level?
Most caudal level with normal motor and sensory function bilaterally
{key muscle tests (3+/5) or “Normal”}
Abnormal interneuron activity in chronic spinal cord injury takes place where?
What are the effects?
- Below level of injury
- Plastic changes bias toward both muscle stretch & cutaneous reflexes
- Hyperreflexia
- Enhanced withdrawal response to cutaneous simuli
What are the mechanical changes in affected muscles in a traumatic spinal cord injury?
- Atrophy, becomes fibrotic, may lose sarcomeres (develop contractures)
- Typical contractures: plantarflexion, knee flexion & hip flexion
What are the autonomic dysfunction in tramumatic spinal cord injury?
- Loss of sympathetic control above T1
- Sympathetics DON’T leave spinal cord until T1
What is autonomic dysreflexia/hyperreflexia?
- Spinal cord cut = NO autonomic control of bladder = reflex emptying
- Send enough “I have to empty” messages that is generates fight or flight response (SNS = inc heart rate, constricts blood vessels)
- Anticipate fight/flight but no fight comes - so the high blood pressure can end up being fatal
- Initiates flight/flight that cannot be controlled/stopped
What are the impaired body temperature regulations associated with traumatic SCI?
- Impaired shunting: cant conserve body heat
- Impaired sweating: cant release body heat
Why is orthostatic hypOtension associated with traumatic SCI?
- Impaired “capacitance” - vessels stay dilated - blood pools in abdomen
- Fine when laying down - but when you stand up it is not ok
