nervous system Flashcards
Herniation syndromes - types
- Cingulate (subfalcine) herniation under falx cerebri
- Downward transtentorial (central) herniation
- Uncal herniation
- cererbellar tosilar herniation into the foramen
Cingulate (subfalcine) herniation can cause
compression of anterior cerebral artery
Downward transtentorial (central) herniation –> … (mechanism and complication)
caudal displacement of brain stem –> rupture of paramedian basilar artery branches –> duret hemorrhages –> usually fatal
Duret haemorrhages are
small lineal areas of bleeding in the midbrain and upper pons of the brainstem.
Uncal herniation - manifestations and mechanism
- compress ipsilateral CN III (blown pupil, down-and-out gaze)
- compress ispilateral PCA (contralateral homonymous hemianopia with macula sparing)
- compress contralateral crus cerebri at tha Kernohan notch (ipsilateral paresis, a false localization sign)
cererbellar tosilar herniation into the foramen magnum - manifestation and mechanism
coma and death result when these herniations compress the brain stem
femoral nerve - functions
- leg flexion at the hip
- leg extension at the knee
- sensation to the anterior thighh and medial leg via saphenous branch
common peroneal nerve - function
gives rise to superficial and deep peroneal nerves
- muscles of the anterior and lateral leg
- sensation to the anterolateral leg and dorsum of the foot
obturator nerve - function
innervates the medial compartment of the thigh and controls adduction
senseation over the medial thight
tibial nerve function
muscles of the posterior compartment of the thight, posterior compartment of the leg, plantar muscles of the foot
- flexion of the knee and digits, platnar flextion of the foot
- sensation to the leg (except medial side) + plantar foot
4% of patients with spinal cord injuries will develop
post-traumatic syringomyelia –> impaired strength and pain pain/Q sensation in the upper extremities
(MRI is diagnostic) (MONTHS TO YEARS LATER)
a potential complication of thoracic aortic aneurysm (and presentation)
anterior spinal cord infraction –> abrupt onset of bilateral FLACCID paralysis and loss of pain/Q sensation below the level of spinal injury)
- UMN signs develops over sevral days
- VIBRATION AND PROPIOCEPTION ARE PRESERVED
acute shoulder pain after forecful abduction and external rotation at the glenohymeral joint suggests
anterior shoulder dislocation (which can cause injury to axillary nerve)
hypoglossal nerve injury can cause ….
etiology
tongue palsy
sergery below te mandible such as for a tumor of the submandibular salivary gland
epidural hematoma - pathogenesis
trauma to sphenoid bone with tearing of middle meningeal artery
epidural hematoma - clinical features
- brief loss of consciousness followed by lucid intercal
- hematoma expansion leads to:
- intracranial pressure
- uncal herniation (ipsilateral CN 3 palsy and hemiparesis)
epidural hematoma - diagnosis
Head CT: binconvex (lens shaped) hyperdensity that does not cross suture lines (no midline shift)
epidural hematoma - treatment
urgent surgical evacuation for symptomatic patients
diffuse axonal injury
results of traumatic acceleartion/deceleration shearing forces that diffusely damage axons in the brain
- coma, head ct: diffuse small bleeds at the grey-white matter junction
Rotator cuff impingement or tendinopathy
pain with abduction, external rotation
subacrosomial tenderness
nroaml range of motion with positive impigement tests
Rotator cuff tear
similar to rotator cuff tendinopathy
- weakness with abduction + external rotation
- older than 40
Interventions for lowering ICP
- head elevation
- sedation (decreased metabolic demand + control hypertension)
- IV mannitol
- Hyperventilation (CO2 washout –> crebral vasoconstriction)
- Removal of CSF (reduction of CSF volume pressure)
common peronia nerve is aka …. / gives rise to
fibular nerve
- superficial + deep peroneal nerves
superficial vs deep peroneal nerves regarding function
superficial: foot eversion, sense on medial and anterio leg
deep peroneal nerve: foot dorsiflexion, toe extension, sense between big and 2nd toes
symptoms onset in subdural hematoma
gradually (1-2 days)
Tic douloureux
aka trigmenial neuralgia: manifests with short burst of excruciating, lancinating pain lasting from seconds to minuts in the distribution of the 2nd and 3rd branches of the V neve (etiology: compression of V)
