8 - Head & Neck - Autonomic Innervation Flashcards
Is the ANS part of the central or peripheral nervous system?
Peripheral nervous system
Name the 4 parasympathetic ganglia in the head and neck:
1) Ciliary
2) Pterygopalatine
3) Submandibular
4) Otic
Which cranial nerves do the parasympathetic fibres hitch-hike on, to reach their target organs?
Preganglionic: III, VII, IX, X
Postganglionic: V
Where do the parasympathetic nerves to the sphincter pupillae and the ciliary body originate from?
Edinger-Westphal nuclei
Brainstem
The parasympathetic nerves from the Edinger-Westphal nuclei hitch-hike on which cranial nerves? What are their target tissues?
Preganglionic = CN III Postganglionic = CN V
Ciliary body
Sphincter pupillae
What effect do the parasympathetic nerves have on the eye?
1) Constrict pupil
2) Accomadation reflex = allows near vision
Where do the parasympathetic nerves to the lacrimal, nasal, submandibular and sublingual glands originate from?
Superior salivary nuclei
Brainstem
The parasympathetic nerves from the Superior salivary nuclei hitch-hike on which cranial nerves?
Preganglionic = CN VII Postganglionic = CN V
Where is the parasympathetic ciliary ganglion located?
Bony orbit
- Between lateral rectus + optic nerve
Where is the parasympathetic pterygopalatine ganglion located?
Pterygopalatine fossa
Where is the parasympathetic submandibular ganglion located?
Inferior to Lingual nerve
Where is the parasympathetic otic ganglion located?
Inferior to foramen ovale
What effect do the parasympathetic nerves have on the salivary and lacrimal glands?
Increase secretion
Where do the parasympathetic nerves to the parotid gland originate from?
Inferior Salivary nuclei
Brainstem
The parasympathetic nerves from the inferior salivary nuclei hitch-hike on which cranial nerves?
Preganglionic = CN IX Postganglionic = CN V
Where do the parasympathetic nerves to the smooth muscle and glands of the trachea, bronchi and GI tract originate from?
Dorsal motor nuclei
Brainstem
The parasympathetic nerves from the dorsal motor nuclei hitch-hike on which cranial nerve?
CN X
The parasympathetic nerves to the head and neck originate from which nuclei in the brainstem?
1) Edinger-Westphal nuclei
2) Superior salivary nuclei
3) Inferior salivary nuclei
4) Dorsal motor nuclei
The sympathetic fibres to the head and neck originate from which vertebral level? At which ganglion of the sympathetic chain do they synapse?
T1
T2
Superior cervical ganglion (C1/2 level)
What are the target tissues of the sympathetic nerves to the head and neck?
- Superior tarsal muscle
- Dilator pupillae
- Sweat glands
- Blood vessels
- Nasal glands
- Salivary glands
Describe the route of the sympathetic nerves from the superficial cervical ganglion to the superior tarsal muscle:
- Wind around internal carotid artery into the skull (to cavernous sinus)
- Joins CN III to superior tarsal muscle
What is the function of the sympathetic nerve which hitch-hikes on CN III?
Helps elevate eyelid
- Superior tarsal muscle
Describe the route of the sympathetic nerves from the superficial cervical ganglion to the dilator pupillae muscle:
- Wind around internal carotids artery into the skull (to cavernous sinus)
- Joins on CN V to dilator pupillae muscle
What is the function of the sympathetic nerve which hitch-hikes on CN V?
Pupillary dilation
- Dilator pupillae muscle
Which artery do the sympathetic nerves which innervate structures in/around the eye hitch-hike on?
Internal carotid artery
Which artery do the sympathetic nerves which innervate blood vessels and sweat glands in the face hitch-hike on?
External carotid artery
What is the function of the sympathetic nerves which wind around the external carotid artery?
- Vasoconstriction
- Sweating
- Decreased secretion of nasal and salivary glands
Why may someone with a lung tumour have miosis, partial ptosis and anhydrosis?
Due to damaged or stretched sympathetic nerves, which arise in the chest (therefore can be damaged by a growth in the chest)
What is the classic presentation of Horner’s syndrome?
- Miosis
- Partial ptosis
- Anhydrosis
What is miosis?
Loss of pupillary dilation = constricted pupil
Why is ptosis due to Horner’s syndrome only partial?
- Paralysis of superior tarsal muscle due to loss of sympathetic innervation
- Levator palpebrae superioris is still functioning, and is able to elevate eyelid partially
List some causes of Horner’s syndrome:
- Pancoast (apex) lung tumour
- Trauma
- Carotid artery dissection
- Spinal cord lesion
What is Horner’s syndrome?
Triad of: Partial ptosis, miosis and anhydrosis affecting 1 side of the face
Due to damaged sympathetic fibres to the head and neck
Which cranial nerves ‘carry’ pre-ganglionic parasympathetic fibres, and what are the ganglia associated with each nerve?
III - Ciliary ganglion
VII - Pterygopalatine + Submandibular ganglia
IX - Otic ganglion
X - Many small ganglia located in target organs (not in head/neck)
Name the nerves which branch off CN VII before it enters the parotid gland:
- Greater petrosal nerve
- Nerve to stapedius
- Posterior auricular nerve
- Chorda tympani
- Nerve to digastric
- Nerve to stylohyoid
Which 2 canals does the facial nerve pass through, and remain intracranial?
1) Internal acoustic meatus
2) Facial canal
Via which foramen does the Facial nerve pass through to become extracranial?`
Stylomastoid foramen
Why does an extradural haemorrhage form a lens shape?
The dura mater is tightly adhered to the periosteum
In which layer of the scalp do blood vessels (supplying the scalp) run in?
Dense connective tissue layer
Name the ganglion which is formed by the facial nerve after the greater petrosal nerve has branched off:
Geniculate ganglion
If a lesion of the facial nerve occurred at the geniculate ganglia, how would the patient present?
- Hyperacusis
- Dry mouth
- Loss of taste
- Paralysed facial muscles
(Greater petrosal nerve has already branched off the facial nerve before the geniculate ganglion)
Name the arteries supplying the side of the scalp and forehead:
- Superficial temporal artery
- Supratrochlear artery
- Supraorbital artery
