Routes of Innervation

Question 1

route of sympathetic innervation

Answer 1

• originate in the brain and passes down the spinal cord
• exits spinal cord at T1-L2 spinal nerves
• travel in sympathetic chains down either side of the vertebral column
• pass into spinal nerves (anterior and posterior rami)
• pass into splanchnic nerves to supply organs

Question 2

head and neck sympathetic innervation pathway

Answer 2

leaves at T1 and ascends within the sympathetic chain and synapses with superior cervical sympathetic ganglion
travels as postsynpatic to internal and external carotid nerves
ICA enters the cranial cavity and nerves follow the ophthalmic artery

Question 3

route of parasympathetic innervation

Answer 3

leaves CNS via CNIII, VII, IX and X and sacral spinal nerve (craniosacral outflow)

Question 4

what are the four parasympathetic ganglia in the head and neck?

Answer 4

ciliary
pterygopalatine
otic
submandibular

Question 5

location of the ciliary ganglion

Answer 5

bony orbit

anterior to optic canal and superior orbital fissure

Question 6

what synapses at the ciliary ganglion?

Answer 6

CNIII

Question 7

what does CNIII become as it synapses at the ciliary ganglion?

Answer 7

post-synaptic ciliary nerve

Question 8

what other fibres pass through the ciliary ganglion?

Answer 8

sympathetic and general sensory fibres but they do not synapse

Question 9

route of CNIII

Answer 9

leaves mid-brain at pons junction
passes through cavernous sinus
enters orbital cavity by exiting superior orbital fissure
divides into inferior and superior to supply extraocular muscles and inferior synapses in ciliary ganglion