Sympathetic Trunk Flashcards

Study the cervical sympathetic trunk, including its ganglia, anatomical course, vascular plexuses, autonomic pathways, and clinical lesions.

Card 1 of 30Question

What is the sympathetic trunk?

A paired longitudinal chain of sympathetic ganglia and connecting nerve fibers extending from the skull base to the coccyx.

In This Section

1. What is the sympathetic trunk?

A paired longitudinal chain of sympathetic ganglia and connecting nerve fibers extending from the skull base to the coccyx.

2. Where is the cervical sympathetic trunk located?

Posterior to the carotid sheath and anterior to the prevertebral muscles, deep to the prevertebral fascia.

3. How many major cervical sympathetic ganglia are typically present?

Three: superior, middle, and inferior cervical sympathetic ganglia.

4. Where is the superior cervical sympathetic ganglion typically located?

Anterior to the longus capitis muscle near vertebral levels C2 to C3, posterior to the internal carotid artery.

5. Which cervical sympathetic ganglion is usually the largest?

The superior cervical ganglion.

6. Where is the middle cervical sympathetic ganglion typically located?

Near vertebral level C6, close to the inferior thyroid artery.

7. Where is the inferior cervical sympathetic ganglion typically located?

Near the neck of the first rib and the C7 to T1 vertebral region.

8. What is the stellate ganglion?

The cervicothoracic ganglion formed by fusion of the inferior cervical and first thoracic sympathetic ganglia.

9. At which spinal cord levels do sympathetic preganglionic neurons originate?

The intermediolateral cell column of spinal cord segments T1 to L2, with some variation extending to L3.

10. How do preganglionic sympathetic fibers reach the cervical sympathetic ganglia?

They enter the thoracic sympathetic trunk through white rami communicantes and ascend before synapsing in cervical ganglia.

11. Are white rami communicantes present in the cervical region?

No. White rami communicantes are restricted to the thoracolumbar spinal nerve levels.

12. What is the function of gray rami communicantes from the cervical sympathetic trunk?

They distribute postganglionic sympathetic fibers to cervical spinal nerves.

13. Which ganglion provides most postganglionic sympathetic innervation to the head?

The superior cervical sympathetic ganglion.

14. Which plexus carries sympathetic fibers from the superior cervical ganglion along the internal carotid artery?

The internal carotid sympathetic plexus.

15. Which sympathetic plexus accompanies branches of the external carotid artery?

The external carotid sympathetic plexus, derived primarily from the superior cervical ganglion.

16. Which muscle of the iris receives postganglionic sympathetic innervation?

The dilator pupillae muscle.

17. Which orbital smooth muscle receives sympathetic fibers that help maintain upper eyelid elevation?

The superior tarsal muscle, also called Muller's muscle.

18. What autonomic functions are supplied by sympathetic fibers distributed to the face?

Cutaneous vasomotor control and sudomotor innervation of sweat glands.

19. Which nerve arises from the internal carotid plexus and joins the greater petrosal nerve?

The deep petrosal nerve.

20. What is formed by the union of the deep petrosal and greater petrosal nerves?

The nerve of the pterygoid canal, also called the Vidian nerve.

21. Do sympathetic fibers synapse in the pterygopalatine ganglion?

No. Postganglionic sympathetic fibers pass through the ganglion without synapsing.

22. Which cardiac nerve arises from the superior cervical sympathetic ganglion?

The superior cervical cardiac nerve.

23. What is the general function of sympathetic cardiac branches from the cervical trunk?

They contribute to the cardiac plexus and help increase heart rate and myocardial contractility.

24. What is the ansa subclavia?

A sympathetic nerve loop around the subclavian artery connecting the middle and inferior cervical ganglionic regions.

25. Which ganglion commonly provides sympathetic fibers to the vertebral artery plexus?

The inferior cervical or stellate ganglion.

26. What is the relationship between the cervical sympathetic trunk and the vagus nerve?

The sympathetic trunk lies posterior to the carotid sheath, while the vagus nerve travels within the sheath.

27. What is Horner syndrome?

A syndrome caused by interruption of the sympathetic pathway supplying the eye and ipsilateral face.

28. What are the classic clinical findings of Horner syndrome?

Ipsilateral miosis, mild ptosis, and variable facial anhidrosis.

29. How can a superior pulmonary sulcus tumor affect the cervical sympathetic pathway?

It may involve the lower cervical or upper thoracic sympathetic pathway, producing Horner syndrome.

30. Why is the stellate ganglion an important target for sympathetic nerve blocks?

Blocking this region can interrupt sympathetic outflow to portions of the head, neck, and upper limb.