Corticospinal Tract
Which gyrus do neurons in the Lateral Corticospinal Tract originate in?
Precentral Gyrus
What is a stroke?
Thrombus (blood clot) that can cause brain damage due to loss of blood flow to area of brain for more than 24 hours
Which artery supplies the Corticospinal Tract in the midbrain?
Paramedian arteries of PCA (posterior cerebral artery)
What does spastic paralysis mean?
Means: Hard & Rigid; shows head tilt, paresis (weakness) of lower facial muscles, elbow flexed, forearm pronated, fingers flexed, hip circumducted, knee extended, foot plantar flexed.
What is Flaccid Paralysis?
Decreased tone of muscles, feels soft (one of the biggest signs)
Name the origin and function of the Corticospinal Tract.
Origin: medial and superior portion of precentral gyrus (Brodmann area 4)
Function: to activate LMNs which innervate flexor muscles of UE and LE, especially distal flexors of wrist and fingers)
What are motor deficits found with Medial Midbrain Syndrome (Weber Syndrome)?
UMN signs for contralateral UE and LE (Hemiplegia or Hemiparesis).
This would mean paramedian arteries of the PCA are affected and the corticospinal tract due to descending through the midbrain.
What artery supplies the Corticospinal Tract in the Medulla?
Anterior Spinal Artery
What does Hyperreflexia mean?
Means over reactive reflexes; response is greater in speed and amplitude as a result of excitability of alpha motor neurons, interneurons, and stretch neurons.
What is Hyporeflexia?
Muscles are less responsive to stimuli
Collection of axons of Corticospinal Tract
You are working with a stroke client who has the clinical signs indicated, hemiplegia and hemianesthesia of left upper and lower limbs. What part of internal capsule is affected? R or L? Anterior Limb or Posterior Limb of the internal capsule?
Right Posterior Limb Internal Capsule
What type of vascular accident results in no brain damage?
TIA : less than 24 hrs, 15-20 mins, results in loss of blood flow to that area
What does Clonus mean?
Means rhythmic contractions, rapid movement between plantarflexion and dorsiflexion
What are signs of muscle atrophy?
Muscle weakness occurring after weeks/months of disuse
What areas of the brain make up the Motor Association Cortex?
Parietal (brodmanns 5,7), Supplementary (superior portion of brodmanns 6), and Premotor (inferior portion of brodmanns 6)
Your client is presenting with loss of touch sensation in their L upper and lower limbs, dizziness, and L hemiparesis. What type of stroke has occurred?
Right side medial medullary syndrome
motor deficits: UMN signs for contralateral UE/LE
SS deficits: loss of discriminative touch and conscious proprioception from contralateral UE/ LE
What is the most common cause for a hemorrhage of lenticulostriate arteries?
Hypertension
What is a positive Babinski reflex?
When large toe extends during flexor plantar response instead of flexing normally
What does the term Fasciculations mean?
Twitches
What is the term for not being able to initiate movements due to damage to the Motor Association Cortex areas? Can produce movement by reflex but cannot voluntarily move.
Apraxia
You are working with a client who had a middle cerebral artery stroke on the left side distal to the lenticulostriate arteries. Which limb is affected?
Right Upper Limb
How does the presentation of an occlusion of the anterior cerebral artery (ACA) differ from an occlusion of the middle cerebral artery (MCA)?
ACA: lower limb
MCA: upper limb and face
At what point does the UMN terminate and become LMN for the Corticospinal tract?
Terminate in the brainstem and spinal cord
At what point do the LMNs terminate?
Terminate in the skeletal muscle