Lecture 11 Flashcards
How are sensory inputs in the face broken down
three regions: V1, V2, V3
Nerve for sensory imputs from the face and branches
trigeminal nerve (CN V), sensory info from face, also have motor branch for chewing (mastication)
Where do branches of trigeminal nerve travel to
Come back to large ganglion where cell bodies of primary sensory neurons are located- trigeminal ganglion sits in merkels cave
Axons travel from these cell bodies and travel back to brainstem (at level of pons) where they synapse on nuclei situated throughout brainstem and upper spinal cord
3 different nuclei that make up trigeminal nucleus
mesocephalic trigeminal nucleus, chief trigeminal nucleus, spinal trigmeninal nucleus
Describe mesocephalic trigeminal nucleus
sits in midbrain, receives info from proprioception of jaw (mastication/chewing)
Describe chief trigmeninal nucleus
receives nerve axons from receptors related to fine touch, corollary of PCML pathwa in face
Pathway of chief trigmeninal nucleus
Nerves sits at rostal pons, synapse on cell bodies for second order sensory neurons which then cross midline and ascend to contralateral thalamus, 3rd order sensory neurons travel to face region of somatosensory cortex
Describe spinal trigeminal nucleus
receives info for crude touch, pain and temp, corollary of anterolateral pathway
Pathway of spinal trigeminal nucleus
axons enter at level of pons and descend to caudal medulla and rostal spinal cord, synapse on cell bodies in these region for second order sensory neurons, cross midline to opposite thalamus to face region of cortex
result of damage to trigeminal nerve
ipsilateral damage
Result of damage to somatosensory cortex of thalamus
contralateral damage
Identify this
mesencephalic tract of CN V
Identify this
Trigeminal ganglion
Identify this
Primary snesory neurons
Identify this
Chief sensory nucleus of CN V
Identify this
Spinal tract of CN V
Identify this
Spinal nucleus of CN V
Describe damage with loss of pain and temp info on left face and right side of body
Damage to lateral pons affecting trigmeminal nerve and anterolatetal pathway. Body has already crosse over, face cross at higher cervical levels
Describe damage to right side of face and right side of body
Damage to the thalamus, where body and face fibers converge, or damage to entire comatosensory cortex on contralateral side (unlikely if purley sensory symptoms)
Describe what spinal cord sydomes can include
can include motor loss, sensory losss or both!
What does spinal cord syndomes loss depend on
areas affected by injury, and pathways affected. Kinds of symptoms/ levels affected dependant on level and location of injury
Damage to various areas of SC results
dorsal horn where primary sensory afferents come in, posterior column carry vibration an position sense, damage these areas sensory loss. Damage to anterolateral pathways, affect pain and temp sense, damage to anterior horn, motor losses
Causes of transverse cord lesion
trauma, tumors, multiple sclerosis
Describe degree/area of damage of transverse cord lesion
entire cord, both sides
Describe symptoms for transverse cord lesion
Motor:
-LMN symptoms for muscles innervated at level of injury, bilaterally
-Damage to lateral corticospinal tract UMN symptyoms for muscles innervated below level of injury
Sensory:
-damage to posterior column and dorsal horn- loss of proprioception, vibration and light touch at mytome at level of injury and below level of injury bilaterally
-damage to anterolateral pathways and commisure- loss of pain, crude touch, temp at level of injury and below level of injury bliaterally
Causes of central cord syndrome
syringomyelia (fluid filled cavity in spinal cord), tumors, multiple sclerosis
Describe degree area of damage of central cord syndrome
small lesion in central part of cord as gets larger involves other areas. Effects posterios column, amnd anterior horn as well as anterior commisure (affects second order sensory neurons anteriorlateral pathway) one/2 segments below.
Causes of posterior cord syndrome
trauma e.g. compression of post cord, tumors in post column, multiple sclerosis (damage to white mater), Vit b12 deficiency
(if severe enough can lead to degeneration of axons that run in posterior column), tabes dorsalis (disease causing degeneration of fibers)
Describe symptoms fpr posterior cord syndrome
If purely damage to PCML pathways, loss of proprioception and light touch. Affects level of injury and levels below injury bilaterally. If have trauma dorsal horn may be affected too.
Motor function, pain and temp function normal
Causes of anterior cord syndrome
trauma, tumors, multiple sclerosis, infarct
Describe area degree/ area of damage of posterior cord
damage to posterior cord, including posterior columns bilaterally
Degree/area of damage of anterior cord syndrome
affects anterior part of cord, bilaterally
Symptoms of anterior cord syndrome
motor:
- LMN symtoms at level of injury bilaterally
- Damage to corticospinal tracts , UMN sumyoms for muscles innervated below level of injury bilaterally
Sensory:
-damage to anterior lateral pathway and anterior commisure loss of pain, temp, crude touch 1 level below injury and all levels below that (preserved sensation at level of injury)
- proprioception, light touch function preserved, comes in dorsal horn.
Causes of hemicord lesion
-associated with brown-sequard syndrome: damage to one half of spinal cord
Causes: penetrating trauma, compression from tumors, multiple sclerosis
Symptoms of Hemicord lesion
Motor:
- damage to anterior horn, LMN symptoms for muscle innervated at level of injury on ipsilateral side
- Damage to corticospinal tract, UMN symptoms for all muscles below level of injury on ipsilateral side
Sensory:
- loss of proprioception, light touch at level of injury and below level of injury ipsilaterally
- Damage to primary sensory neuron and second order sensory neuron, Loss of pain and crude touch for strip of dermatomes at level of injury and one segment below on ipsilateral side
- loss of pain and temp for dermatomes 2 segments and below on contralateral side
