4.2 Autonomic Innervation

Question 1

Where do sympathetic fibres originate?

Answer 1

Thoracic region T1-T6 of spinal cord

Question 2

Describe the sympathetic chain.

Answer 2

Spans from base of the skull to the coccyx formed by nerve fibres and ganglia.

Question 3

Sympathetic ganglia of significance of head and neck?

Answer 3

Superior, middle, inferior cervical

Question 4

Describe the sympathetic trunk.

Answer 4

Preganglionic fibres mainly arise in first thoracic neural segment and synapse in one of the 3 cervical sympathetic ganglia.
After synapsing, posganglionic fibres travel with ICA or ECA to target tissues.

Question 5

Describe the location of the superior cervical ganglion.

Answer 5

Posteirorly to carotid artery and anterior to C1-C4 vertebrae

Question 6

Which nerves originate from the superior cervical ganglion?

Answer 6

Internal carotid nerve
- Structures in eye, pterygopalating A and ICA
External carotid nerve
- Smooth muscles of arteries
Nerve to pharyngeal plexus
- combines with vagus and glossopharyngeal nerves
Superior cardiac branch
- cardiac plexus in the thorax
Nerves to CN II, III, IV, VI, IX.
Gray rami communicantes
- Sympathetic fibres to anterior rami of C1-C4

Question 7

What structures do the ICN and ECN follow?

Answer 7

ICA -ICA

ECN - Common and ECA

Question 8

What vertebral level is the middle cervical ganglion located?

Answer 8

C6,

anterior to inferior thyroid A.

Question 9

What postganglionic fibres come from the middle cervical ganglion?

Answer 9

Gray rami communicantes
Thyroid branches
- Travel along inferior thyroid A
Middle cardiac branch
- cardiac plexus in thorax

Question 10

What vertebral level is the inferior cervical ganglion located at?

Answer 10

C7, anteriorly

Question 11

What postganglionic fibres come from the inferior cervical ganglion?

Answer 11

Gray rami communicates
Branches to subclavian and vertebral arteries
- Smooth muscle present in the A.
Inferior cardiac nerve
-cardiac plexus

Question 12

What is the stellate ganglion?

Answer 12

Combination of the inferior cervical ganglion and the 1st thoracic ganglion.

Question 13

Describe the parasympathetic trunk.

Answer 13

Nerves applying head and neck are situated in 4 nuclei int he brainstem.
Each is associated with a cranial nerve that carrier the fibres out of the brain to a peripheral ganglion near target viscera.
Postganglionic fibres ocntinue to the structures they innervate.

Question 14

What are the pairs of parasympathetic ganglia in the head? Associated nuclei?

Answer 14

Ciliary gangliion - Edinger-westphal
Pterygopalatine - superiorsalivatory
Submandibular- superior salivatory
Otic - inferior salivatory

Question 15

Where is the ciliary ganglion located?

Answer 15

• Lies in the Orbital Cavity, anterior to the superior orbital fissure, lateral to the optic nerve

Question 16

Describe the preganglionic fibres of the ciliary ganglion.

Answer 16

the ciliary ganglion is supplied by fibres from the Edinger-Westphal nucleus (associated with oculomotor nerve)

Question 17

Describe the postganglionic fibres of the ciliary ganglion.

Answer 17

the parasympathetic fibres leave the ganglion via the short ciliary nerves. These fibres continue into the orbit to innervate the structures of the eye.

Question 18

What are the target organs of ciliary ganglion fibres

Answer 18

the post-ganglionic fibres from the ciliary ganglion innervate:
o Sphincter Pupillae (pupil contraction)
o Ciliary Muscles (accommodation)

Question 19

Describe sensory fibres and sympathetic fibres travelling with the postganglionic fibres from the ciliary ganglion.

Answer 19

• Sensory fibres from the eyeball, innervating the cornea, ciliary body and iris pass to the nasociliary nerve

• Sympathetic Fibres come from the Superior Cervical Ganglion
o Via the plexus on the Opthalmic Artery (First branch of the Internal Carotid Artery)
o Distributed to the eyeball, innervate the dilator pupillae muscle

Question 20

Where is the pterygopalatine ganglion located?

Answer 20

• Lies in the Pterygopalatine Fossa – space located inferiorly to the base of the skull.

Question 21

Describe the preganglionic fibres of the pterygopalatine ganglion.

Answer 21

o The pterygopalatine ganglion is supplied by fibres from the superior salivatory nucleus (associated with the facial nerve).
o These fibres travel within the greater petrosal nerve and the nerve of the pterygoid canal to reach the ganglion.

Question 22

Describe the postganglionic fibres of the pterygopalatine ganglion

Answer 22

o Parasympathetic fibres leave the ganglion by hitch-hiking on branches of the Maxillary nerve (V2)

Question 23

What are the target organs of pterygopalatine ganglion fibres

Answer 23

o The post ganglionic fibres from the pterygopalatine ganglion provide secretomotor innervation to the:
• Lacrimal gland
• Mucous glands of the posterosuperior nasal cavity
• Nasopharynx
• Palate.

Question 24

Describe sensory fibres and sympathetic fibres travelling with the postganglionic fibres from the pterygopalatine ganglion.

Answer 24

• Sympathetic fibres come from the Superior Cervical Ganglion
o Via the plexus on the Internal Carotid Artery
o Distributed to the nose, palate and nasopharynx

• Sensory fibres from the nose, palate and nasopharynx pass in the branches of the ganglion to the Maxillary Nerve (CN V2)

Question 25

Where is the submandibular ganglion located?

Answer 25

• Suspended from the Lingual Nerve by small branches on the surface of hypoglossus

Question 26

Describe the preganglionic fibres of the submandibular ganglion.

Answer 26

o The ganglion is supplied by fibres from the superior salivatory nucleus (associated with the facial nerve). o These fibres are carried within the Chorda Tympani. o This nerve hitch-hikes along the lingual branch of the mandibular nerve to reach the ganglion.

Question 27

Describe the postganglionic fibres of the submandibular ganglion

Answer 27

o Fibres leave the ganglion and travel directly to the submandibular and sublingual glands.

Question 28

What are the target organs of submandibular ganglion fibres

Answer 28

o Secretomotor innervation to • Submandibular Gland • Sublingual Gland

Question 29

Describe sensory fibres and sympathetic fibres travelling with the postganglionic fibres from the submandibular ganglion.

Answer 29

• Sympathetic fibres come from the Superior Cervical Ganglion o Along the Facial Artery o Pass to the glands in the floor of the oral cavity • Taste fibres may pass through the ganglion

Question 30

Where is the otic ganglion located?

Answer 30

• Located inferiorly to the foramen ovale

Question 31

Describe the preganglionic fibres of the otic ganglion.

Answer 31

From inf. salivatory nucleus | Travel with lesser petrosal nerve of CNIX

Question 32

Describe the postganglionic fibres of the otic ganglion

Answer 32

Auriculotempral nerve of CNV3 hitchhike to parotid

Question 33

What are the target organs of otic ganglion fibres

Answer 33

Secretmotor or parotid gland

Question 34

Describe the vagus nerve parasympathetic.

Answer 34

Travel within vagus nerve, many ganglia located within target tissues. Smooth muscle of bronchi, trachea and GI tract

Question 35

Why does hornet's syndrome occur?

Answer 35

Interruption of cervical sympathetic trunk. | Manifests as absence of sympathetically stimulated functions on ipsilateral side.

Question 36

What are the features of hornet's syndrome?

Answer 36

Miosis - Constriction of pupil due to paralysis of dilator pupillae - sphincter pupillae of pupil is sympathetic, unopposed action Ptosis Dropping of superior eyelid Paralysis of smooth muscle fibres interdigitated with the aponeurosis of legator palpebrae superiors in superior tarsal muscle. Anhydrosis Absence of sweating Same side of face as lesion Loss of innervation to the sweat glands of the face Vasodilation -Loss of sympatheticc tone Increased temp and redness of skin

Question 37

What is the cervical plexus? Where is it located?

Answer 37

Network of nerve fibres that supply innervation to some of the structures in the neck and trunk. Located in the posterior triangle of the neck, halfway up the SCM and within the prevertebral layer of cervical fascia.

Question 38

Where does the cervical pleas originate

Answer 38

C1 - C4 spinal nerves anterior fibres

Question 39

What are the muscular branches of the cervical plexus?

Answer 39

Phrenic nerve - C3, C4, C5 Motor and sensory to diaphragm Sensory to mediastinum Nerve to geniohyoid and thyrohyoid C1 Ansa cervicalis C1, C2, C3 Infrahyoids

Question 40

What are the sensory branches of the cervical plexus?

Answer 40

Greater auricular nerve C2 and C3 Sensation to external ear and skin over parotid Transverse cervical nerve C2, C3 Sensation to anteiror neck Anterolateral skin of neck and upper sternum Lesser occipital nerve C2 Posteiror scalp cutaneous Supraclavicular Nerves C3, C4 Sensation over suprascapular fossa and upper thoracic region

Question 41

Where is entry for cervical nerve block? Who should you be carful of? Why?

Answer 41

Erb's point - middle of posterior border of SCM Regional anaesthesia for neck surgery Affects phrenic nerve so should not bet performed on cardiac patients.