Localization Flashcards
Upper Motor Neuron Lesion
Location: Descending from brain (cortex) to spinal cord (synapse 1 at cell body of anterior horn)
- weakness: Extensors of upper extremities; Flexors of lower extremities
- spastic paralysis: Especially Flexors of upper extremities, and Extensors of LE
- increased reflexes
- increased tone
- difficulties with fine motor control
- positive Babinski reflex
- positive clasp knife spasticity
Lower Motor Neuron Lesion
Location: PNS (leaving the spinal cord to synapse at the NMJ)
- weakness: follows distribution of the motor unit
- atrophy
- fasciculations: simultaneous discharge of whole motor unit
- Fibrillations: spontaneous contraction of a single muscle fiber
- decreased reflexes and tone
- flaccid paralysis
Primary Sensory Cortex
- Post-Central Gyrus (Parietal Lobe)
- Brodmann areas 3, 1 and 2
Primary Motor Cortex
- Pre-Central Gyrus (Frontal Lobe)
- Brodmann area 4
Lateral Corticospinal Tract
Function: Descending voluntary movement of contralateral limbs
1st Order Neuron: Motor cortex descends through the internal capsule, then decussates at the CAUDAL/LOWER MEDULLA (PYRAMIDAL DECUSSATION); descends contra laterally
Synapse 1: Cell body of the anterior horn
2nd Order Neuron: leaves spinal cord
Synpase 2: NMJ
Bell’s Palsy vs. LMN Lesion vs. UMN Lesion
Bell’s Palsy: Complete destruction of Cranial Nerve VII: The whole face loses tone
LMN Lesion: Ipsilateral paralysis of upper and lower face
UMN Lesion: Lesion occurs between the motor cortex and the facial nucleus
- Only CONTRALATERAL paralysis of LOWER FACE
- Forehead is spared due to bilateral UMN innervation
Myotomes
- Diaphragm
- Deltoid
- Tricep
- the muscles that are innervated by specific spinal cord roots
- Diaphragm: C3, C4 and C5
- Deltoid: C5
- Tricep: C7
Dermatomes
- Thumb, Digits 1&2
- Medial Hand
- Big toe
- Heel
- sensory areas that tell you what segment of the spinal cord is effected
- Thumb, Digits 1&2: C6
- Medial Hand/pinky: C8
- Big toe: L5
- Lateral foot/Heel: S1
Deep Tendon Reflexes
- Biceps
- Triceps
- Biceps: C5
- Triceps: C7
Pronator Drift Test
- Hold arms out and close eyes
- Positive test: One arm drifts down and pronates; indicates UMN Cortical Spinal Tract Lesion
Dorsal Column/Medial Lemniscal Pathway
Function: Ascending
- Pressure
- Vibration
- Fine Touch
- Propioception
1st Order Neuron: Cell body in Dorsal Root Ganglion enters spinal cord and ascends ipsilaterally in Dorsal Column
Synapse 1: Medulla (Ipsilateral Nucleus cuneatus or gracilis)
2nd Order neuron: Decussates in medulla, ascends contralaterally to the medial lemniscus
Synpase 2: VPL Thalamus
3rd Order: Sensory Cortex
Spinothalamic Tract
Lateral: Pain & Temperature
Anterior: Crude Touch & Pressure
1st Order: Sensory nerve endings/Cell body in Dorsal root ganglion enters the spinal cord
Synapse 1: Ipsilateral gray matter in spinal cord
2nd Order: Decussation at anterior white commissure, ascending contra laterally
Synapse 2: VPL Thalamus
3rd Order: Sensory Cortex
VPL (ventroposterior lateral) nucleus
receives sensory information from your body
VPM – ventroposterior medial nucleus
receives sensory information from your face
- Is more Superior to the VPL; facial sensory information crosses at level above High Pons
LGN (Lateral geniculate nucleus)
receives visual/optical information
medial geniculate nucleus:
receives hearing
Frontal Lobe
- motor control
- executive functions (initiating, planning, self-check, ability to pay attention)
- Broca’s area (in dominant hemisphere): Motor speech
Lesion:
- IPSILATERAL GAZE
- Aphasia if in dominant (usually left) hemis
- inattention
- contralateral weakness
- perseveration: repetition of words or phrases
Parietal Lobe
- the sensory lobe.
- Position in space, proprioception, having a sense of direction, sensory command
Lesion:
- Hemineglect (Contralateral): Lesion in non-dominant (usually right) side
- anesthesia
- thermalgesia
- apraxia
- graphasthesia
- asterognosia
Temporal Lobe
- Primary Auditory cortex
- Wernicke’s Area (dominant hemisphere): receptive language
- Memory (episodic-lifetime, academic-semantic)
Lesion:
- central deafness
- receptive aphasia
- amnesia
Occipital Lobe
- Principal visual cortex (BRODMANN AREA 17)
Lesion:
- dyslexia
- contralateral hemianopia
- impaired recognition of colors
Fasciculus Cuneatus
Dorsal column pathway for upper body and upper extremities
Fasciculus Gracilis
Dorsal column pathway for lower body and lower extremities
Brown-Sequard Syndrome
Hemisection of spinal cord:
- Ipsilateral UMN signs/Corticospinal tract
- Ipsilateral dorsal column damage (tactile, vibration, propioception sense)
- Contralateral spinal thalamic damage (Pain & temp)
Syringomyelia
- Syrinx at central spinal cord epands and damages the anterior white commissure of the spinothalamic tract
- Results in bilateral, CAPE-LIKE distribution loss of pain and temperature sensation
- Usually at level of C8-T1
