Session 5 Flashcards
(10 cards)
Where do sympathetic nerves arise from?
The thoracolumbar spinal column T1 -> L2
Describe how the sympathetic nerves travel from the spinal cord to the head and neck
They travel up the sympathetic chain to synapse with cervical ganglia in the neck. Most synapse at the superior cervical ganglion at the top of the sympathetic chain (some middle cervical). They then “hitchhike” on the blood vessels and on CNV distally to reach their target tissues.They travel to the face (sweat glands and smooth muscle) or eye.
Pathology involving what structures can cause autonomic dysfunction in the eye and face?
Carotid arteries and lung apex
What is Horner’s syndrome and how does it present?
Damage to the sympathetic fibres along their course to the head and neck. Miosis (constricted pupil), partial ptosis and anhydrosis.
Which cranial nerves carry parasympatheitc fibres from the brainstem?
CNIII, CNVII, CNIX, CNX
What are the 4 parasympathetic ganglia in the head and neck?
Cilary (CNIII)
Pterygopalatine and submandibular (CNVII)
Otic (CNIX)
How are postganglionic parasympathetic fibres carried to their target tissues?
With the trigeminal nerve (except vagus)
What is the difference between the signs seen in Horner’s Syndrome and those seen in an
oculomotor nerve lesion?
In a lesion of CNIII the ptosis is usually more severe (a greater proportion of muscles keeping the eye open are voluntary), eye is in down an out position and the pupil is dilated not constricted.
Describe how lesions at different points along the facial nerve lead to different outcomes in parasympathetic function
At or before geniculate ganglion - all parasympathetic functions
After geniculate ganglion - does not involve petrosal nerve (lacrimal gland spared)
Further along - all parasympathetic functions may be spared (chorda tympani also given off) however facial expression is affected.
Why does increased intracranial pressure affect parasympathetics of CNIII first?
They are on the outside of the nerve.
