Week 3 Flashcards
Where do the posterior column and corticospinal tracts cross over?
the medulla oblongata
Where does the spinothalamic tract cross over?
the spinal cord
give examples of incomplete spinal injuries
central cord syndrome anterior cord syndorme posterior cord syndrome Brown-Sequard syndrome cauda equina syndrome
Describe central cord syndrome
typically older patients
hyperextension injury
compression of cord anteriorly by osteophytes and posteriorly by ligametum flavum
Describe Brown-Sequard syndrome
hemi-section of spinal cord
stab / gun shot wounds
paralysis of affected side
pain and temperature loss on opposite side below the lesion
Describe cauda equina syndrome
bony compression or disc protrusion in lumbar or sacral region back pain bowel and bladder dysfunction leg numbness and weakness saddle parasthesia
What is spinal shock?
temporary suppression of all reflex activity below the level of injury
immediate
babinski’s sign is first to reappear
Describe spinal shock
flaccid paralyis areflexia loss of sensation bladder bowel
What are the stages of spinal shock?
arefelxia
initial reflex return
hyperreflexia - spasticity
What is the clinical triad in neurogenic shock?
hypotension
bradycardia
hypothermia
What are the signs of an upper motor lesion?
muscle weakness
increased tone
increased refelxes
What are the signs of a lower motor neuron lesion?
muscle weakness and wasting
reduced tone
reduced reflexes
fasiculations
Describe tendon jerk reflexes
involuntary stereotyped response to a stimulus
reflex muscle contractions produced by muscle stretch
Tendon jerks are useful as a neurological test
Describe a monosynaptic circuit
stimulus - tendon tap activates muscle spindle receptors conduction along afferent fibres transmission at synapses between afferent and motor neurons conduction along efferent motor fibre excitiation contraction coupling Twitch contaction of skeletal muscle
Describe Jendrassik’s manoeuvre
massive motor common, some excitation overflows to lumbar sacral segments, means neurons can get excited more easily
WHat is the purpose of the stretch reflex?
it acts to maintain constant muscle length and control of muscle tone.
Sensitivity of this reflex is controlled by the brain
What are the clinical effects of spinal shock?
flaccid paralysis
areflexia
loss of sensation
loss of bladder and bowel reflexes
What are the stages of spinal shock?
arefelxia
initial refelx return
initial hyperreflexia
hyperreflexia and spasticity
Describe upper motor neuron lesions
no muscle wasting no fasiculations spastic weakness hyperreflexia positive babinksi response
Describe lower motor neurone lesions
muscle wasting fasciculations flaccid muscle loss in bulk reduced or absent reflexes negative babinski response
What is tinnitus?
perception of sounds in the absence of external auditory stimulus
What is vertigo?
illusion of motion
objective -person is moving and environment is stationary
Subjective - person is stationary and environment is moving
What is the triad caused by meniere’s disease?
vertigo
tinnitus
hearing loss
WHat are some of the suggested mechanisms of menniere’s disease?
increased production of endolymph
decreased production of perilymph accompanied by compensatory over production of endolymph
Decreased absorption of endolymph
Give examples of focal injury
scalp, skull, intracranial haemorrhage, brain (laceration/contusion)
Give examples of diffuse injuries
traumatic axonal injury, ischaemia, swelling
Describe extradural haematomas
most with skull fracture
middle meningeal vessels
young adults
lucid interval then deterioration
Describe subdural haematomas
bridging veins
acute / chronic
gradual deterioration
increased ICP
What protein accumulates near the site of injury?
amyloid precursor protein
What is brain ischaemia a consequence of?
raised ICP
hypoxaemia
reduced cerebral perfusion pressure
What are the common symptoms of concussion?
headache
dizziness
memory disturbance
balance problems
What are the signs of concussion?
loss of consciousness
seizure
incoordination
irritable
