Spinal Nerves and their Distribution Flashcards
Why might you want to access the vertebral canal?
Sample CSF for blood or organisms
Measure the pressure of CSF
Injection of anaesthetics
Injection of antibiotics
Injection of chemotherapeutic agents
Why is access safest in the lumbar region
Spinal cord ends at L1/L2
Subarachnoid space extends to S2
Cauda equina unlikely to be damaged
When wouldn’t you do a lumbar puncture?
If a patient has raised intracranial pressure
Can lead to coning- fatal
Where does L4 lie?
Between iliac crest
In a lumbar puncture, where should the needle go through?
Between L3 and L4
L4 and L5
What does a dermatomyotome split into?
Cells which differentiate ventrally and dorsally
What is produced from the cell that differentiate ventrally from the dermatomyotome?
Hypaxial muscles
Anterior muscle wall and anterior limb muscles
What is produced from the cell that differentiate dorsally from the dermatomyotome?
Epaxial muscles- true back muscles
What is the defining characteristic of a true back muscle?
Innervated by dorsal rami
Where do dorsal root ganglia develop?
Neural crest
What is shingles caused by?
Varicella Zoster virus
Describe how varicella zoster virus causes shingles?
Enter as chicken pox
Hides out in dorsal root ganglion
Virus reactivated in later life and rash will appear the skin related to that dorsal root ganglion
What can ventral rami form?
Plexuses
What are the different components of of a reflex?
Receptor
Sensory neuron
Integration centre
Motor neuron
Effector
