Anatomy of Sympathetic Cervical Ganglia

- Superior Cervical Ganglion (SCG): is the largest of the cervical ganglia and embedded within soft tissue anterior to the transverse processes of the C2-C3 vertebrae.
- Middle Cervical Ganglion(MCG): is the smallest of the cervical ganglia and is often absent and is located anterior to the transverse process of the C6 vertebra, usually beneath the inferior thyroid artery
- Stellate Ganglion: located anterior to the transverse process at the level of the C6 vertebra, superior to the subclavian artery & the posterior aspect of the pleura, and posterior to the vertebral vasculature
Although all of the cervical ganglia supply postganglionic fibers to the head and neck region, the SCG is the primary contributor via the oculosympathetic pathway (OSP)
Sympathetic pathway to head and neck ( 3 order neurons):
- First-order neurons descend from the hypothalamus to synapse in the intermediolateral (IML) gray substance of the spinal cord at the levels C8-T2 (known as the Ciliospinal Center of Budge-Waller)
- Second-order neurons exit the Ciliospinal Center of Budge-Waller via white rami communicantes and ascend through the stellate and middle cervical ganglia (without synapsing) and culminating with synapse in the superior cervical ganglion
- Third-order neurons exit the superior cervical ganglion as postganglionic fibers that travel with either the internal or external carotid artery to reach their final destination.
Branches of Superior Cervical Ganglion
1. Internal carotid nerve: The internal carotid nerve travels with the internal carotid artery, eventually forming a plexus of nerves that innervate the internal carotid artery, and critical eye structures (Müller's muscles, pupillary dilator muscles, orbital vasomotor muscles, and lacrimal glands).
2. External carotid nerve: The external carotid network of nerves travel with the common and external carotid arteries to innervate the smooth muscle of arteries and the sweat glands of the face.
3. Gray rami communicantes: Some post-ganglionic fibers distribute to spinal nerves of vertebral levels C1-C4
4. Nerve to pharyngeal plexus: One of the post-ganglionic neurons travels to the pharyngeal plexus, where it becomes intertwined with branches from the vagus and glossopharyngeal nerves.
5. Superior cardiac nerve: The superior cardiac nerve travels to the thoracic cavity to reach the cardiac plexus.
Branches of Middle Cervical Ganglion
1. Inferior thyroid nerves: Some post-ganglionic fibers travel along the inferior thyroid artery to innervate the esophagus, pharynx, trachea, and larynx.
2. Gray rami communicantes: Post-ganglionic fibers distribute to spinal nerves of C5-C6 vertebral levels.
3. Middle cardiac nerve: The middle cardiac nerve travels to the thoracic cavity to reach the cardiac plexus
Branches of Inferior Cervical/Stellate Ganglion
1. Nerves to subclavian and vertebral arteries: Branches to these vessels innervate the smooth muscles in the arteries.
2. Gray rami communicantes: Post-ganglionic fibers route to the spinal nerves of C7, C8, and T1.
3. Inferior cardiac nerve: The inferior cardiac nerve travels to the thorax and contributes to the cardiac plexus.
Clinical Relevance of Cervical sympathetic ganglia
Horner Syndrome
Horner syndrome can occur due to damage along any point in the OSP including at preganglionic (first- and second-order neurons) and postganglionic (third-order neurons) fibers.
Cardinal symptoms of Horner syndrome are
1. ptosis (drooping of upper eyelid),
2. miosis (decrease in pupil size),
3. anhidrosis (lack of sweat production).
4. Conjunctival hyperemia due to vasodilation of capillaries secondary to sympathetic denervation is a transient acute sign of HS
Pharmacologic testing with cocaine followed by hydroxyamphetamine can help to diagnose Horner Syndrome and then localize the lesion as preganglionic or postganglionic.
- First-Order Neuron Lesions (Preganglionic): Pharmacologic provocation will show reduced pupillary dilation with cocaine administration, followed by an increase in dilation after administering hydroxyamphetamine.
Examples: Hypothalamic lesions, syringohydromelia, multiple sclerosis, spinal cord neoplasms
- Second-Order Neuron Lesions (Preganglionic): Pharmacologic testing with cocaine and hydroxyamphetamine will have the same results as first-order lesions.
Examples: Pancoast tumors, sympathetic schwannomas, neuroblastic tumors, goiters
- Third-Order Neuron Lesions (Postganglionic): Testing with cocaine solution will show reduced pupillary dilation relative to the normal eye, but hydroxyamphetamine application will reveal no dilation since postganglionic fibers will become depleted of norepinephrine.

[@layanalnosani9577]

I had my head and neck exam today and I think I aced it ! I literally don’t know what I would have done without your h&n playlist! Thank you so much for your efforts!

[@EasyAnatomy]

Layan Alnosani I am so glad to hear that AlhamdulAllah. I wish if I had enough time to provide all students with more videos in shorter time. May o ask you which university are you in?

[@layanalnosani9577]

@@EasyAnatomy sure king abdulaziz university

[@EasyAnatomy]

Layan Alnosani If the one in Jeddah, One of my former Ph D students there as professor in the Department of Maxillofacial Surgery

[@shwshwbw]

Excellent

[@ATIFBSHAFI75]

Excellent. I love the way of explaining. Thanks a lot Professor.

[@donussayn3454]

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[@leonardodavinci9814]

6:40 so the postganglionic branches of ggl. cervicale superius are gonna CREATE internal carotid nerve that’s gonna make the plexus?

[@EasyAnatomy]

Yes

[@practicalanatomy2297]

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[@user-wc5pu1is8w]

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[@msbewhatever]

first!!!