Neurology of the Thorax

Question 1

Constrictions of the esophagus (4)

Answer 1

At the cricopharyngeal m.
At the aortic arch
At the left bronchus
At the esophageal hiatus of the thoracic diaphragm

Question 2

Branches of the vagus n.

Answer 2

Left vagus n. gives off the left recurrent laryngeal n. (loops under ligamentum arteriosum).
Right vagus n. gives off the right recurrent laryngeal n.(loops under the brachiocephalic trunk).
Gives pulmonary branches, cardiac branches (superior, middle, inferior), and esophageal branches.

Question 3

Anterior vagal trunk is mostly from:

Answer 3

Left vagus n.
Anterior to esophagus.
Enters abdomen via esophageal hiatus.

Question 4

Posterior vagal trunk is mostly from:

Answer 4

Right vagus n.
Posterior to esophagus.
Enters abdomen via esophageal hiatus.

Question 5

Route of the phrenic n.

Answer 5

Anterior rami of C3-5.

Travels into the space between mediastinal parietal pleura and fibrous pericardium to innervate the diaphragm.

Question 6

Typical intercostal nerves

Answer 6

3rd-6th

Question 7

Atypical intercostal nerves

Answer 7

1st-2nd and 7th-11th

Question 8

Branches of the typical intercostal ns. (5)

Answer 8

Rami communicantes
Collateral branches
Lateral cutaneous branches
Anterior cutaneous branches
Muscular branches

Question 9

What makes the 1st intercostal n. “atypical”?

Answer 9

No cutaneous branches and mostly joins the brachial plexus.

Question 10

What makes the 2nd intercostal n. “atypical”?

Answer 10

It is known as the intercostobrachial n.

Question 11

What makes 7th-11th intercostal ns. “atypical”?

Answer 11

They do not exist entirely between ribs so they are termed thoracoabdominal ns.

Question 12

4 general principles of the autonomic nervous system

Answer 12

1. Sympathetic stimulation is catabolic.
2. Parasympathetic stimulation is anabolic.
3. Parasympathetic stimulation has a limited distribution (head, neck, trunk), whereas sympathetic is distributed throughout the body.
4. Glandular secretion (except sweat glands) is stimulated by PSNS, the SNS causes vasoconstriction which leads to a decrease in non-sweat gland glandular secretion.

Question 13

Sympathetic division is from:

Answer 13

Thoracolumbar T1-L2

Question 14

Route of presynaptic fibers

Answer 14

Lateral horn to anterior root to anterior ramus to paravertebral ganglia of sympathetic chain.

Question 15

Synaptic options (3)

Answer 15

1. Presynaptic fibers can enter the paravertebral ganglion and synapse onto postsynaptic neuron in the same level.
2. Presynaptic fibers enter the paravertebral ganglion and travel up or down the sympathetic chain and synapse with a postganglionic neuron there.
3. Presynaptic fibers enter paravertbral ganglion and exit without synapsing and continue through an abdominopelvic splanchnic n. on the way to a prevertebral ganglion where its postsynaptic neuron is.

Question 16

Cell bodies of postsynaptic fibers exist in:

Answer 16

Paravertebral or prevertebral (4) ganglia.

Question 17

4 prevertebral ganglia

Answer 17

Celiac ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Aorticorenal ganglion

Question 18

Cardiac splanchnic ns.

Answer 18

Postsynaptic fibers that become part of superficial and deep cardiac plexuses.
T1-5

Question 19

Pulmonary splanchnic ns.

Answer 19

Postsynaptic fibers that become the pulmonary plexus.

T2-3

Question 20

Abdominopelvic splanchnic ns.

Answer 20

Travel from thoracic sympathetic trunk to prevertebral ganglia.
Gives off greater, lesser and least splanchnic ns.

Question 21

Greater splanchnic n.

Answer 21

T5-9.

Sends fibers to esophageal plexus and to the celiac ganglion in abdomen.

Question 22

Lesser splanchnic n.

Answer 22

T12

Sends fibers to aorticorenal ganglion.

Question 23

Parasympathetic innervation of the thorax is from:

Answer 23

Cranial ns. (CN III, VII, IX, X)

Vagus n. and its branches.

Question 24

Thoracic autonomic plexuses (4)

Answer 24

Pulmonary plexus
Cardiac plexus
Aortic plexus
Esophageal plexus

Question 25

Pulmonary plexus

Answer 25

Mixed
Sympathetic is from pulmonary splanchnic ns.
Parasympathetic is from pulmonary branches of the vagus n.

Question 26

Cardiac plexus

Answer 26

Mixed
Sympathetic is from cardiac splanchnic ns.
Parasympathetic is from superior, middle and inferior cardiac branches of vagus n.
Postsynaptic fibers end near the SA and AV nodes.

Question 27

Aortic plexus

Answer 27

Mixed

Sympathetic and parasympathetic contributions are both continuous with the superficial cardiac plexus.

Question 28

Esophageal plexus

Answer 28

Mixed
Sympathetic is from greater splanchnic n.
Parasympathetic is form esophageal branches of vagus n.