Flashcards in Neurosurgery Cortex Deck (368)
what is the function of the corticobulbar tracts
contains UMN of the cranial nerves to provide innervation of the face, head and neck
they innervate the cranial motor nuclei bilaterally
(except the hypoglossal nuclei and the lower facial nuclei which are innervates contralaterally only)
explain the differences between a UMN and LMN facial paly
7th CN nucleus in pons
upper half of nucleus= upper half of face and same for lower and lower
upper half of nucleus receive motor input bilaterally, lower half of nucleus recieves only contralateral info
UMN will have paralysis of contralateral lower facial muscles with forehead sparing (as info from other side)= central facial palsy
LMN will have paralysis of the ipsilateral half of the face= bells palsy
what tracts originate from the brainstem and control involuntary movements
what is the role of the vestibulospinal tract, and where does it originate
originates from the vestibular nucleus in the pons
it controls balance and posture by innervating the antigravity muscles (extensor for legs, flexor for arms)
what is the origin and function of the reticulospinal tract
Originates from the reticular formation in the medulla and pons:
The pontine reticulospinal tract facilitate voluntary/reflex responses and increases tone.
The medullary reticulospinal tract inhibits voluntary/reflex responses and decreases tone (think dulling down)
what is the origin and function of the rubrospinal tract
Originates from the red nucleus in the midbrain. It excites flexor muscles and inhibits extensor muscles of the upper body.
what is the origin and function of the tectospinal tract
Originates from the superior colliculus in the midbrain. It co-ordinates movements of head and neck to vision stimuli.
how many vertebrae all together
what does C1 lack
a spinous process or body
what is different about C2
has dens (ondontoid process)
what is different about C3-4
have short and bifid spinous processes
where does the posterior ligament run
within vertebral canal, posterior to the vertebral bodies
what does the ligamentum flavum do
It runs vertically connecting the lamina of adjacent vertebrae. It helps maintain an upright posture and assist straightening the spine after flexion.
where are LP done
what are the layers a needle has to go through in an LP
what is the usual age range for mechanical back pain
when is mechanical back pain worse
morning stiffness which resolves with movement
pain is made worse by prolonged sitting or when rising from a seated position
what can happen when facet joints are hypertrophied
patients will get referred pain from the nerve supplying the facet join that mimics sciatica, but doesn't radiate below the knee
describe a paramedian prolapse
compresses travering disc
describe a far lateral prolapse
compress the exiting nerve
what can a central/ medial herniation cause
lumbar stenosis or if large enough CES
what is radiculopathy
dysfunction of a nerve root causing dermatomal sensory deficit with weakness of the muscle groups supplied by the nerve
what is sciatic pain like
Shooting pain radiating from the buttocks down to the posterior knee/leg. The pain can be exaggerated by coughing or sneezing.
what does a straight leg raise test positive mean
with the patient lying down on their back, lift the patient's leg while the knee is straight. If the angle to which the leg can be raised before eliciting the patient's sciatic pain is <45° then the test is said to be positive.
what are the clinical features of an L5/S1 prolapse disc involing S1 root
Pain along the posterior thigh with radiation to the heel.
Weakness of plantar flexion (on occasion).
Sensory loss in the lateral foot.
Reduced or absent ankle jerk.
what are the clinical features of an L4/5 prolapse affecting L5
Pain along the posterior or posterolateral thigh with radiation to the dorsum of the foot and great toe.
Weakness of dorsiflexion of the toe or foot.
Paraesthesia and numbness of the dorsum of the foot and great toe.
Reflex changes unlikely.
what are the clinical features of an L3/4 prolapse affecting L4
Pain in the anterior thigh.
Wasting of the quadriceps muscle.
Weakness of the quadriceps function and dorsiflexion of foot.
Diminished sensation over anterior thigh, knee and medial aspect of lower leg.
Reduced knee jerk.
what are the indications for a discectomy following a prolapse
Failure of conservative treatment (physiotherapy and analgesia) - First line management
Central disc prolapse: Patients with bilateral sciatica or other features indicating a central disc prolapse, such as sphincter disturbance and diminished perineal sensation, should be investigated promptly.
if what reflex is present does it make it unlikely to be CES