This document provides information to help localize neurological deficits based on symptoms and signs. It discusses localization in the upper motor neuron system including the cortex, corona radiata, internal capsule, brainstem, and spinal cord. It also discusses localization in the lower motor neuron system including the anterior horn, root/plexus, and nerves. Localization is guided by features like patterns of weakness, sensory loss, reflex changes, and specific cranial nerve involvement.

1. LOCALIZATION IN CLINICAL NEUROLOGY http://crisbertcualteros.page.tl

2. NEUROANATOMY

6. LOWER VS. UPPER MOTOR NEURON

7. Localization in the Upper Motor Neuron (Pyramidal) System Principle: Tone is increased,causing spasticity and hyperreflexia Site Symptoms S igns Cortex Differential weakness Fractionated limbs and face weakness (arms>face and leg) Sensory symptoms Aphasia.hemianopia. or hemineglect Language, visual or Cortical and primary attentional alterations sensory loss Cognitive dysfunction

9. Site Symptoms Signs Corona Differential weakness Fractionated weakness Radiata of limbs and face Primary sensory loss Internal Weakness only Face, arm and leg affected Capsule equally and densely Brainstem Unilateral or bilateral Dense hemiparesis weakness Ocular or oropharyngeal Diplopia or vertigo weakness dysarthria or dysphagia Spinal Cord Difficulty with gait No face involvement Difficulty walking Spastic quadriparesis Urinary incontinence (cervical) or paraparesis (thoracic) Sensory level

14. Localization Within the Brain Stem Principle: Specific cranial nerve involvement guides localization Site Signs and Symptoms Midbrain Impaired vertical gaze >CN 3 palsy (plus contralateral ophthalmoplegia (INO) >CN 4 palsy Contralateral motor signs (hemiparesis suggests Weber’s syndrome, ataxia suggests Claude’s syndrome Tremor or chorea suggests Benedikt’s syndrome Alterations in consciousness, perception or behavior (peduncular hallucinosis)

16. Site Signs and Symptoms Pons Dysarthria and dysphagia Contralateral hemiparesis or hemisensory loss Ipsilateral facial nerve loss (CN5) Ipsilateral gaze palsy (paramedian pontine reticular formation PPRF) or one and a half syndrome (PPRF and MLF) Locked in syndrome (bilateral basis pontis with ocular bobbing) Horizontal nystagmus (brachium pontis) Ataxia

18. Pontomedullary Vertigo (CN 8) Junction Dysarthria Horizontal or vertical nystagmus Contralateral hemisensory loss and hemiparesis Lateral Ipsilateral Horner’s syndrome Medulla Ipsilateral limb ataxia (Wallenberg) Ipsilateral face and contralateral body numbness Gait ataxia Vertigo, dizziness (CN 8) Dysphagia (CN 9, 10, 12 palsies) Medial medulla Hemiplegia Contralateral posterior column sensory loss Ipsilateral tongue weakness (12)

22. Localization in the Spinal Cord Site Signs and symptoms Causes Hemicord Ipsilateral hemiparesis Penetrating trauma (Brown Contralateral spino- Extrinsic cord Sequard) thalamic sensory loss compression Ipsilateral dorsal column sensory loss; spinchter dysfunction Anterior Upper and lower Anterior spinal artery cord motor paralysis infarction Spinothalamic (often T4-T8) sensory loss Spinchter dysfunction Sparing of posterior column Central Paraparesis Syringomyelia cord Lower motor Neck flexion-extension injury paralysis; wasting and fasciculations in arms Sensory loss in “shawl” distribution (cervical)

25. Posterior Proprioceptive Vit B12 def cord and vibratory Demyelination Segmental tingling (ms) and numbness Extrinsic Sensation of compression constricting “bands” Foramen Spastic quadriparesis Tumor magnum Neck and pain (meningioma, stiffness chordoma) C2 to C4 and upper atlantoaxial facial numbness subluxation Ipsilateral Horner’s syndrome Ipsilateral tongue and trapezius muscle

27. Conus Lower sacral saddle Intrinsic tumor medullaris sensory loss (S2-S5) Extrinsic cord Spinchter dysfunction compression impotence; aching back or rectal pain L5 and S1 motor deficits (ankle and foot weakness) Cauda Spinchter dysfunction Extrinsic tumor equina Paraparesis with Carcinomatous weakness in the meningitis distribution of multiple Arachnoiditis roots Spinal stenosis Sensory loss in multiple bilateral dermatomes

30. Localization in the Lower Motor Neuron System Principle: Tone is decreased, causing flaccidity and hyporeflexia Site Symptoms Signs Anterior horn Progressive flaccid Wasting, weakness, weakness fasciculation No sensory loss Root/plexus Single limb Weakness in radicular/ weakness and plexus distribution sensory loss Electromyogram Pain in the neck (EMG) shows back or limb denervation in affected muscles

31. Site Symptoms Signs Nerve Focal weakness Focal or distal (mononeuritis) weakness Distal weakness Atrophy in affected (polyneuropathy) distribution Fasciculations Hyporeflexia Slowing or low amplitude on conduction studies denervation on EMG Neuromuscular Fluctuating Positive edrophonium weakness test Diplopia Decremental response with repititive stimulation on EMG