Neurology of the Thorax Flashcards
Constrictions of the esophagus (4)
At the cricopharyngeal m.
At the aortic arch
At the left bronchus
At the esophageal hiatus of the thoracic diaphragm
Branches of the vagus n.
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.
Anterior vagal trunk is mostly from:
Left vagus n.
Anterior to esophagus.
Enters abdomen via esophageal hiatus.
Posterior vagal trunk is mostly from:
Right vagus n.
Posterior to esophagus.
Enters abdomen via esophageal hiatus.
Route of the phrenic n.
Anterior rami of C3-5.
Travels into the space between mediastinal parietal pleura and fibrous pericardium to innervate the diaphragm.
Typical intercostal nerves
3rd-6th
Atypical intercostal nerves
1st-2nd and 7th-11th
Branches of the typical intercostal ns. (5)
Rami communicantes Collateral branches Lateral cutaneous branches Anterior cutaneous branches Muscular branches
What makes the 1st intercostal n. “atypical”?
No cutaneous branches and mostly joins the brachial plexus.
What makes the 2nd intercostal n. “atypical”?
It is known as the intercostobrachial n.
What makes 7th-11th intercostal ns. “atypical”?
They do not exist entirely between ribs so they are termed thoracoabdominal ns.
4 general principles of the autonomic nervous system
- Sympathetic stimulation is catabolic.
- Parasympathetic stimulation is anabolic.
- Parasympathetic stimulation has a limited distribution (head, neck, trunk), whereas sympathetic is distributed throughout the body.
- Glandular secretion (except sweat glands) is stimulated by PSNS, the SNS causes vasoconstriction which leads to a decrease in non-sweat gland glandular secretion.
Sympathetic division is from:
Thoracolumbar T1-L2
Route of presynaptic fibers
Lateral horn to anterior root to anterior ramus to paravertebral ganglia of sympathetic chain.
Synaptic options (3)
- Presynaptic fibers can enter the paravertebral ganglion and synapse onto postsynaptic neuron in the same level.
- Presynaptic fibers enter the paravertebral ganglion and travel up or down the sympathetic chain and synapse with a postganglionic neuron there.
- 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.
Cell bodies of postsynaptic fibers exist in:
Paravertebral or prevertebral (4) ganglia.
4 prevertebral ganglia
Celiac ganglion
Superior mesenteric ganglion
Inferior mesenteric ganglion
Aorticorenal ganglion
Cardiac splanchnic ns.
Postsynaptic fibers that become part of superficial and deep cardiac plexuses.
T1-5
Pulmonary splanchnic ns.
Postsynaptic fibers that become the pulmonary plexus.
T2-3
Abdominopelvic splanchnic ns.
Travel from thoracic sympathetic trunk to prevertebral ganglia.
Gives off greater, lesser and least splanchnic ns.
Greater splanchnic n.
T5-9.
Sends fibers to esophageal plexus and to the celiac ganglion in abdomen.
Lesser splanchnic n.
T12
Sends fibers to aorticorenal ganglion.
Parasympathetic innervation of the thorax is from:
Cranial ns. (CN III, VII, IX, X)
Vagus n. and its branches.
Thoracic autonomic plexuses (4)
Pulmonary plexus
Cardiac plexus
Aortic plexus
Esophageal plexus
Pulmonary plexus
Mixed
Sympathetic is from pulmonary splanchnic ns.
Parasympathetic is from pulmonary branches of the vagus n.
Cardiac plexus
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.
Aortic plexus
Mixed
Sympathetic and parasympathetic contributions are both continuous with the superficial cardiac plexus.
Esophageal plexus
Mixed
Sympathetic is from greater splanchnic n.
Parasympathetic is form esophageal branches of vagus n.
