Neuro Cases Flashcards
What does degeneration of the corticospinal tract cause?
Positive Babinski sign!
What can damage to the corticobulbar tract cause?
Contralateral face paralysis and deviation of tongue upon protrusion
What can damage to the corticospinal tract cause?
Contralateral hemiparesis, hyperreflexia, positive babinski
What spinal cord segments innervate the thenar, hypothenar and interosseus muscles?
C8-T1
In the patient with Syringomyelia, why were tactile sensibility, joint position and vibration sense spared?
Dorsal Column/Medial Lemniscus Tract doesn’t cross through the anterior white commissure. [The spinothalamic tract does!]
Do segmental signs of atrophy indicate an UMN or LMN?
LMN lesion. UMN lesions present initially as flaccidity (spinal shock), then as increased muscle tone. LMN lesions present as atrophy/flaccidity.
What nerve supplies the Hypothenar & Interosseus muscles?
Ulnar Nerve (C8 & T1)
What nerve supplies the thinner muscles?
Median nerve (C5, C6, C7) + (C8, T1) (Recurrent branch)
What does syringomyelia cause?
Progressive loss of sensation in both upper extremities and back of neck. Loss of pain and temperature sensation.
What is the mechanism of syringomyelia?
- Excess CSF in the central canal of spinal cord is called hydromyelia.This excess CSF is secreted by the ependymal cells.
- When fluid dissects into he surrounding white matter forming a cystic cavity or syrinx, the term syringomyelia is applied.
- The cyst forms along the spinal canal and as it grows it eventually compresses the anterior white commissure. This is the location of crossing for the secondary neurons of the spinothalamic tract.
- The diffuse nature of the pain and temperature loss can be attributed to the primary neurons ascending and descending 1-2 spinal segments in lisseurs tract.
What would syringomyelia look like on an MRI?
You would see a cyst (dark for T1, white for T2) between C5-T1.
What area does syringomyelia harm in the spinal section?
Central circle coving the anterior white commissure.
What does decreased proprioception on the right mean?
Damage to the medial lemniscus on the left.
What does right upper & lower extremity weakness, increased reflexes and a positive babinski sign (toes in extension) indicate?
Damage to the left corticospinal tract.
What does a tongue deviating to the left mean?
Left hypoglossal nucleus has been damaged. (or right UMN)
What does the corticospinal tract control?
Motor information
What does the medial lemniscus tract control?
Sensory information
If there is damage to the left corticospinal tract, left medial lemniscus and left hypoglossal nucleus, where is the lesion?
Medial medulla - in medial lemniscus on left side
What is the blood supply to the medial medulla (left side of medial lemniscus)?
Left Anterior Spinal Artery (Left ASA) - middle branch off the two vertebral arteries
What condition does blockage of the anterior spinal artery cause?
Medial medullary syndrome (weakness in right upper and lower extremities, tongue deviates to the left).
