Monoparesis or Monoplegia Flashcards
where are neuronal cell bodies of the motor neuron unit?
cervical intumescence: C6-T2
lumbar intumescence: L4-S3
is the spinal cord the same length as the vertebral column?
no: spinal cord is shorter
where does the C8 nerve exit?
caudal to C7 vertebra
multiple spinal nerves will merge to form a ___________________
named nerve
what are the main components of the motor unit that can be affected in disease?
nerve root
spinal nerve
specific named nerve
what are the clinical signs of a neurologic deficit to one limb?
lameness
dragging toes
non weight bearing
muscle atrophy
pain
abnormal proprioception
reduced spinal reflexes
abnormal sensory function in autonomous zones
self mutilation
what is lameness due to neurologic disease due to?
irritation or compression of a nerve root or nerve
what can lower motor neuron disorders of one leg involve?
one named nerve
group of nerves in one leg
what do spinal reflexes involve?
receptors and nerves of the peripheral nervous system (sensory and motor) and the spinal cord
which spinal cord segments are involved in withdrawal of thoracic limbs?
C6-T2
which nerve is involved in the perineal reflex?
pudendal
which nerve is involved in the patellar reflex?
femoral
what are some differentials due to trauma?
brachial plexus avulsion
nerve trauma
what is neurapraxia?
transient interruption of nerve function and conduction
no physical disruption of axon
what is axonotmesis?
separation of axons from neuronal cell body and subsequent degeneration of distal axon
what is neurotmesis?
complete severance of the nerve and physical disruption of axons and myelin sheaths
what is damage due to in brachial plexus avulsion?
overdistension of nerve
degree and location of damage
what does a brachial plexus avulsion of cranial C6-C7 look like?
flexion of elbow reduced or absent: musculocutaneous nerve
what does horner’s syndrome with brachial plexus avulsion indicate for localization?
intraforaminal C8-T2
what is a skin complication with brachial plexus avulsion?
self mutilation
how is the prognosis of brachial plexus avulsion with denervated elbow extensors (weight bearing)?
return to function poor
what is the best prognostic indicator for brachial plexus avulsion?
presence of pain perception/nociception
what are tumors of nerves known as?
peripheral nerve sheath tumors
where do peripheral nerve sheath tumors originate?
usually originate peripherally
where are the most common sites for a peripheral nerve sheath tumor?
caudal cervical and cranial thoracic
what do peripheral nerve sheath tumors initially cause?
lameness: nerve root signature
what can be found as time progresses with a peripheral nerve sheath tumor?
neurogenic muscle atrophy
mass appreciated: axilla for brachial plexus
can peripheral nerve sheath tumors affect the cutaneous trunci reflex and sympathetic fibers?
yes
which peripheral nerve root tumors carry the best prognosis?
distal peripheral nerve sheath tumors
what happens in degenerative lumbosacral stenosis?
narrowing of the spinal canal and subsequent compression of caudal equina
what can intervertebral disc protrusion and soft tissue proliferation occuring laterally result in?
nerve root entrapment
who is usually impacted by degenerative lumbosacral stenosis?
middle aged or older
large breed dogs: german shepherds
where do C2-C7 spinal nerves exit?
cranial to same number vertebra
where do the T1-S3 spinal nerves exit?
caudal to associated vertebra
which components of the motor unit are usually affected in disease?
nerve root
spinal nerve
specific named nerve
what is nerve root signature?
lameness due to neurologic cause
what do we test clinically for thoracic limb reflexes?
withdrawal only
what pelvic limb reflexes do we test?
withdrawal reflec
patellar reflex
perineal reflex
what can be seen on a caudal C8-T2 avulsion?
reduced/absent weight bearing
reduced/absent cutaneous trunci reflex
partial or complete horner’s syndrome
what does horner’s syndrome with brachial plexus avulsion indicate?
intraforaminal C8-T2 localization
what is the process of degenerative lumbosacral stenosis?
intervertebral disc degeneration and narrowing of disc space
thickening of interarcuate ligament, epidural fibrosis and thickening of capsules of articular processes
