Spinal Cord Flashcards
Lies within the vertebral canal
Spinal Cord
The spinal cord is protected by three surrounding fibrous membranes called
Meninges
The spinal cord is held in position on EACH SIDE by the
Denticulate ligament
The spinal cord is held in position INFERIORLY by the
Filum terminale
The anterior part of the spinal cord contains which kinds of root?
Motor Roots
The posterior part of the spinal cord contains which kinds of root?
Sensory Roots
The spinal cord terminates in the adult at the level of
Lower border of first Lumbar vertebra
T or F:
The gray matter of the spinal cord is inside
True
Laminae of Rexed -groupings:
Located in the posterior horn
Laminae I-VI
Laminae of Rexed -groupings:
Located at the lateral horn
Lamina VII
Laminae of Rexed -groupings:
Located at the anterior horn
Laminae VIII and IX
Laminae of Rexed -groupings:
Gray substance surrounding the central canal
Lamina X
Ascending Tract:
Position sense 2 pt discrimination Fine, discriminative Vibration sense Stereognosis
Dorsal/Posterior Column
Ascending Tract:
Touch and Pressure
Anterior Spinothalamic Tract
Ascending Tract:
Pain and Temperature
Lateral Spinothalamic Tract
Provides voluntary controlof skeletal muscles
Pyramidal System
The pyramidal system which provides voluntary control of skeletal muscles consists of:
Corticobulbar
Lateral Corticospinal
Anterior Corticospinal
The pyramidal cells can be found at the
Primary motor cortex
Axons of pyramidal cells descend in the
Internal capsule
T or F:
Axons extend into the brainstem and spinal cord to synapse on lower motor neurons
True
Located at the lower medulla, axons decussate the midline to enter on the oppositeside of the SC
LCST
Descending pathways referred to as
Upper Motor Neurons
Motor cellsin the Anterior gray hornof the SCand motor nucleiof the cranialnervesare the final common pathwaysfor the control of skeletal muscle activity; referred to as
Lower Motor Neurons
Signs of Motor Neuron Lesions (UMNL or LMNL)
Paralysis is spastic
UMNL
Signs of Motor Neuron Lesions (UMNL or LMNL)
Clonus (+)
UMNL
Signs of Motor Neuron Lesions (UMNL or LMNL)
Pathologic Reflexes (+)
UMNL
Signs of Motor Neuron Lesions (UMNL or LMNL)
Muscle Tone is decreased
LMNL
Signs of Motor Neuron Lesions (UMNL or LMNL)
Paralysis is Flaccid
LMNL
Signs of Motor Neuron Lesions (UMNL or LMNL)
Atrophy (+)
LMNL
Signs of Motor Neuron Lesions (UMNL or LMNL)
Muscle tone is increased
UMNL
Lesion of Corticospinal Tract (Contra/ipsilateral)
Above the level of decussation
Contralaterally
Lesion of Corticospinal Tract (Contra/ipsilateral)
Below the level of decussation
Ipsilaterally
Paralysis of all four extremities
Quadriplegia
Bilateral cervical spinal cord damage C4 –C6 may result in paralysis of
All four extremities
Quadriplegia
Unilateral spinal cord lesionsin thoraciclevels may result in
Paralysis of the ipsilateral lower extremity
Monoplegia
If the thoracic spinal cord damage is bilateral
Both lower extremities may be paralyzed
Paraplegia
Follows acute damage to the Spinal cord; temporary interruption of the function of SC following injury
Spinal Shock
Time frame of spinal shock
less than 24 hrs or may persist for as long as 1 to 4 weeks
Determination of spinal shock is by testing the activity of the
Anal sphincter reflex
Signs and Symptoms of SPINAL SHOCK
Flaccid, areflexic paralysis
Complete loss of sensation
Loss of autonomic function
Loss of reflex activity -paralysis of the bladder and rectum
Progressive cavitation around the central canal; loss of pain & temperature sensationsin hands & forearm ( common in cervical)
Syringomyelia
Attacks the anterior horn cellsleading to LMNL
Poliomyelitis
Caused by neurosyphilis; dorsal root involvement with secondary degeneration of dorsal columns( loss of vibration and position sense)
Tabes Dorsalis
Pure motor diseaseinvolving the degeneration of anterior horn cells(LMNL) and corticospinal tract(UMNL); NO sensory loss
Amyotrophic lateral sclerosis
Caused by vitamin B12 deficiency; degeneration of posteriorand lateral columns( loss of position sense and vibration in legs associated with UMNL)
Subacute combined degeneration
It is a spinal cord hemisection
Brown-Sequard’s syndrome
Contralateral loss of pain & temperature
Ipsilateral loss of proprioception
Ipsilateral manifestations of upper and
lower motor neuron lesions
Brown-Sequard’s syndrome
Area of the skin supplied by the somatosensoryfibers from a single spinal nerve
Dermatomes
Useful in localizing the levels of lesions
Dermatomes
LOSS OF PAIN AND THERMAL SENSATIONS on the CONTRALATERAL SIDE about 1 –2 segments below the level of the lesion
Anterolateral System
Clinical Signs of Injury to the Lemniscal Pathway
Inability to recognize limb position Astereognosis Loss of two point discrimination Loss of vibration sense (+) Romberg sign
A patient who can stand with feet together and the eyes open, but who sways and falls when the eyes are closed
(+) Romberg sign
Sign that indicates an absence of position sensein the lower limbs
Romberg Sign
