Difference between vertebralcanal and Cranium?

- Epidural space in vertebral canal = real

   there is fat, place for things to expand and grow

- Epidural space in Cranium = fake

   pus, blood, tumor will push cause brain to be pushed on

2 spots where nerve axis gets into trouble?

1. Foramen Magnum - where have transition between SC and medulla of bs can get compression of SC
-2 vertebral arteries - supply BS where RAS is...run transverse foramena and then 2 right angles before going through the foramen magnum - at risk of compression
-tonsils of cerebellum - bumps on bottom of cerebellum -in cases where there is inc. cranial pressure in post cranial fossa the brain can be displaced down into the foramen magnum = tonsilar herniation...crushes opening of ventricular system of SC

2. tentorium  cerebelli inssisure - bs comes through here

if get a midline shift ..can compress BS and RAS will compress and NE will stop = coma due to severe hyperpolarization

also CN 3 also resides here - so when compressed see fixed and dilated pupils and you know that the BS is in trouble

Cauda Equina is made up of?

= roots of the SN

• roots are specific in their function
• SN are mixed
• So if injure CE then you simply have pure sensory or pure motor findings

Cortical Efferent layer

located here are ther:

pyramids on the ventral surface of the medulla + cerebral peduncles on the ventral surface of midbrain

both are part of the cortico spinal pathway - so if see hemorhage here must check for motor control

locus coreleus

• group of cholinergic neurons that have ascending and descending projections of NE to SC and cortex
• keeps us alert, conscious, circadian rhythms behaving
• does this by volumetric release of NE so that NE holds us as threshold and ready for activity
• at some point the NE does dec and you become tired

Upper motor neuron damage

• strength decreased
• tone increased
• stretch reflexes increased = hyperactive reflexes
• atrophy - mild
• clonus
• pathological reflexes arise - babinski
• spastic paralysis - weakness of fine voluntary movements

Lower motor neuron damage

• flaccid paralysis
• atrophy of m
• no primitive reflexes - no babinski
• strengthed dec
• tone dec
• stretch reflexes - dec = hyporeflexive
• fasciculations and fibrilations (spont contraction of m and motor n dies)