×
MedSchool: Ace Your OSCEsThe Medical Company
 
 
 
 
 
GET - On the App Store
View
Upper Limb Neuro
 
 

Motor Assessment

 
 
 
Bookmark
On this page:The Motor Pathway

Overview

Neurological causes of weakness may be delineated into upper motor neuron (brain, brainstem or spinal cord) or lower motor neuron (nerve root, plexus or peripheral nerve) causes. These two broad groups manifest with specific findings elicitable on examination.
  • Causes of Weakness

  • Upper Motor Neuron

  • CNS lesions - decreased power with increased tone, clonus and reflexes.Ischaemia, SAH / ICH, tumour, trauma, encephalitis, vasculitis, MS, ADEM, PML, sarcoidosis, prions
  • Lower Motor Neuron

  • Nerve root pathology - loss of a single myotomeTrauma, radiculopathy, neoplasm
  • Focal peripheral nerve pathology - in the muscles supplied by a single nerveTrauma, entrapment, focal ischaemia, sarcoidosis, neoplasia, Bell’s palsy (face)
  • Axonal pathology (peripheral neuropathy)Diabetes, motor neurone disease, hypothyroidism, B12 / folate deficiency, alcoholism, connective tissue disease, amyloid / sarcoidosis, toxins
  • Peripheral demyelinationGuillain-Barré syndrome, Charcot-Marie-Tooth
  • Other

  • Neuromuscular pathologyMyasthenia gravis, amyloidosis
  • Muscular pathologyPolymyositis, rhabdomyolysis
  • Poor compliance with examination

The Motor Pathway

Upper Motor Nucleus
Primary motor cortex (precentral gyrus)
 
Central Pathway
Corticobulbar tract
(via cerebral peduncle)
Decussation
Medullary Pyramids
Spinal Pathway
Lateral corticospinal tract
 
Lower Motor Nucleus
Ventral horn at the level of entry into the spinal cord
 
Neuromuscular Junction
 
 
Muscle
Next Page
----------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Want more info like this?
  • Your electronic clinical medicine handbook
  • Guides to help pass your exams
  • Tools every medical student needs
  • Quick diagrams to have the answers, fast
  • Quizzes to test your knowledge
Sign Up Now
   
 
 

Snapshot: Initialising...