Flashcards in Motor systems II Deck (25):
what is the origin of the corticotectal tract? termination?
1. occipital lobe 2. oculomotor accessory nuclei, superior colliculus (projects to medial longitudinal fasciculus to nuclei of CN 3, 4, 6)
what is the origin of the tectospinal tract? termination?
1. superior colliculus 2. C and T spinal cord levels
what is the function of the corticotectal / corticospinal tracts?
reflex movement of the eyes, neck (head), and upper thorax in response to auditory, vestibular, and/or cutaneous stimuli
how does the rubrospinal tract control movement of the hands and digits?
1. facilitating motor neurons that innervate the digital flexors of the UL 2. inhibiting the motor neurons that innervate the distal extensors of the UL
the rubrospinal and reticulospinal tracts consist of what type of neurons?
the medial (pontine) reticulospinal tract is excitatory to which muscles?
paravertebral and limb extensors
what is the effect of the medial (pontine) reticulospinal tract on paravertebral and limb FLEXORS?
what is the effect of the lateral (medullary) reticulospinal tract on paravertebral and limb FLEXORS?
what is the overall function of the medial and lateral reticulospinal tracts?
modulation of muscle tone and posture maintenance
what is the function of the medial vestibulospinal tract?
1. maintenance of balance in response to vestibular input 2. control of head movement to keep an image on the retina
what is the function of the lateral vestibulospinal tract?
1. excitatory to antigravity muscles (trunk paravertebral and proximal limb extensors) 2. inhibits LMNs that innervate limb flexors
what are the descending tracts of the anteromedial group?
1. anterior corticopinal 2. medial and lateral vestibulospinal 3. medial and lateral reticulospinal 4. tectospinal
what is the general function of the descending tracts of the anteromedial group?
gross movements of axial trunk and proximal limb to maintain balance as postural adjustments are made
what are the descending tracts of the lateral group?
1. lateral corticospinal 2. rubrospinal
what is the general function of the descending tracts of the lateral group?
influence movement of distal muscles of limb (fingers)
what descending tract makes up the cortical group?
lateral corticospinal (only terminates on lower motor neurons)
what is the general function of the descending tract of the cortical group (lateral corticospinal)?
mediate distinct, fractionated movements of the digits (eg typing)
what is the arrangement of cell bodies of motor neurons in the ventral horn, from medial to lateral?
TSAFH (trunk, shoulder, arm, forearm, hand)
what characterizes Brown-Seguard syndrome?
1. loss of discriminative touch at and below lesion (ipsilateral) 2. loss of pain and temperature 1-3 segments below lesion (contralateral) 3. loss of reflex activity at level of lesion (ipsilateral) 4. UMN signs below level of lesion (ipsilateral) 5. LMN signs at level of lesion (ipsilateral)
poliomyelitis affects what part of the spinal cord? what is the result?
1. ventral horns 2. LMN lesion signs
combined systems disease is characterized by degeneration of what areas? what are the results?
1. dorsal funiculus - loss of discriminative touch, two point discrimination, vibratory sense, proprioception; sensory ataxia 2. lateral funiculus - UMN signs (Babinski, hyperreflexia, muscle weakness, spasticity)
the anterior spinal artery supplies what area of the spinal cord?
anterior 2/3 (anterior and lateral funiculi and gray matter)
the posterior spinal artery supplies what area of the spinal cord?
posterior 1/3 (dorsal funiculi and posterior part of dorsal horns)
occlusion of the anterior spinal artery could result in what deficits?
1. loss of pain and temperature sensation (anterolateral system) 2. LMN weakness (anterior horn) 3. UMN signs (lateral corticospinal tracts) 4. incontinence (descending pathways)