Posterior Mediastinum Flashcards
how long does the esophagus extend?
C6 - T11
position of the esophagus?
posterior to trachea, anterior to thoracic vertebrae in superior mediastinum
what forms the esophageal plexus of nerves?
right and left vagus nerves
describe the location of the left laryngeal recurrent nerve?
branches off the left vagus nerve, curves under the aortic arch and back up along the esophagus and trachea
where are the possible narrowings of the esophagus?
- junction of esophagus and pharynx
- where esophagus is crossed by the aortic arch
- where the esophagus is compressed by the left main bronchus
- at the esophageal hiatus
blood supply to the esophagus
- thoracic aortic esophageal branches
- bronchial arteries
- the ascending branches of the left gastric artery (distal portion)
what passes through the esophageal hiatus?
- esophagus
- vagus trunks
- esophageal branches of left gastric artery
where is the esophageal hiatus?
T10
what passes through the caval foramen opening?
- inferior vena cava
- terminal branches of right phrenic nerve
- lymphatic vessels from liver
what passes through the aortic hiatus?
- abdominal aorta
- thoracic duct
- azygos vein
what provides parasympathetic innervation to thoracic and abdominal viscera?
vagus nerves
where do the vagus nerves pass?
posterior to lung roots
innervation of esophagus?
vagus nerves form esophageal plexus
trace the left vagus nerve?
branches to form the left recurrent laryngeal nerve, passes posterior to lung roots to form the esophageal plexus, then become anterior and posterior vagal trunks near diaphragm
what relays pain information from the esophagus?
visceral afferents from sympathetic trunks
what relays info about normal physiological process back to CNS for esophagus?
visceral afferents (parasympathetic) from the vagus nerves
where does the thoracic aorta begin?
T4
where does the thoracic aorta end?
T12 as it passes through the diaphragm
location of the thoracic aorta relative to the vertebral column?
left of vertebral column superiorly, then anterior to the vertebral column inferiorly
branches of the thoracic aorta
BEMPPSS
- bronchial
- esophageal
- mediastinal
- pericardial
- posterior intercostal (3-11)
- superior phrenic
- subcostal
what drainage does the azygos vein receive?
the right posterior intercostal veins as high as the 5th intercostal space, then dumps into the superior vena cava
what drainage does the hemiazygos vein receive?
the left lower posterior intercostal veins (9,10,11,12), then crosses around T9 to drain into azyos vein
what drainage does the accessory hemiazygos vein receive?
left posterior intercostal veins 5-8, then drains into azygos vein
what is the right superior intercostal vein?
a single vessel formed by the junction of the 2-4 posterior intercostal veins that drains into the azygos vein
what is the left superior intercostal vein?
receives left posterior intercostal veins 2-4 and drains into the accessory hemiazygos vein
what supplies posterior intercostal arteries 1-2?
supreme intercostal artery off of the costocervical trunk
what supplies anterior intercostal arteries 1-6?
internal thoracic artery
what supplies anterior intercostal arteries 6-11?
musculophrenic artery
what supplies posterior intercostal arteries 3-11?
thoracic aorta
what is the thoracic duct?
principal channel of lymphatic flow, beginning as a confluence of lymphatic trunks in the abdomen
where is the thoracic duct located?
posterior mediastinum, posterior to esophagus in between aorta and azygos vein
what does the thoracic duct receive?
all regions of the body below the diaphragm, left side of thorax, head and neck, left upper limb
what drains into the right lymphatic duct?
right upper limb, right side of thorax, head and neck
where does the thoracic duct drain into?
junction of the left subclavian and left internal jugular veins
where does the thoracic duct enter?
through the aortic hiatus, posterior to the esophagus into the inferior portion of the superior mediastinum
what is the cisterna chyli?
the beginning of the thoracic duct, receiving all lower limb lymph
what are the sympathetic trunks?
a major component of the sympathetic portion of the ANS, 2 parallel cords along the vertebral column with 10-12 ganglia
how are the ganglia of the sympathetic trunks connected to the spinal cord?
they are connected to adjacent spinal nerves by white and gray rami communicantes
what branches off of the sympathetic trunks?
greater, lesser, and least splanchnic nerves
where do the splanchnic nerves travel to?
contain sympathetic preganglionic fibers going to viscera in the abdominal cavity
where are preganglionic cell bodies of the ANS located?
gray matter of CNS (brain or spinal cord)
what are the 2 neuron chains in the ANS?
preganglionic neuron, postganglionic neuron, the two synapse in a ganglion
what is another name for sympathetic divison
thoracolumbar
what is another name for parasympathetic division
craniosacral
where are preganglionic cell bodies in the sympathetic (thoracolumbar) division?
in the intermediolateral (between dorsal gray horn and ventral gray horn) cell column at T1-L2 spinal cord levels
where are preganglionic fibers in the parasympathetic (craniosacral) division?
contained in CN3, CN7, CN9, CN10, and S2-4 spinal cord levels
describe the lengths of pre and postganglionic fibers in the sympathetic divison?
- preganglionic fibers are SHORT, because ganglia are near the CNS
- post ganglionic fibers are LONG
describe the lengths of pre and postganglionic fibers in the parasympathetic divison?
- preganglionic fibers are LONG, because the ganglia are located a distance from the CNS
- postganglionic fibers are SHORT, because the ganglia are associated with target organs
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the liver?
T6-T9
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the stomach?
T6-T9
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the pancreas?
T6-L2
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the kidneys?
T10-L1
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the spleen?
T6-T8
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the duodenum?
T8-T10
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the jejunum?
T9-T10
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the ileum?
T8-T10
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the cecum/appendix?
T10
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the ascending colon?
T10
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the transverse colon?
T11
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the descending colon?
T12-L1, L2
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the sigmoid colon?
S2
what segment is involved in spinal sensory/sympathetic/visceral afferent pain innervation of the rectum?
S4
upon entering a sympathetic trunk ganglion a preganglionic fiber may do? (3)
- synapse with a ganglionic neuron within the same ganglion
- ascend or descend the sympathetic trunk to synapse in another trunk ganglion
- pass through the trunk ganglion and emerge without synapsing - uses splanchnic nerve to exit instead of gray rami communicans
what is within a white rami communicans?
always pre-ganglionic fibers from T1-L2 spinal cord levels
what is within a gray rami communicans?
always post-ganglionic fiber
what is the white rami communicans?
bundle of preganglionic fibers that are myelinated that travel toward the sympathetic chain ganglia from the ventral horn
follow the path of a normal synapse at the level of entry?
preganglionic sympathetic fibers from T1-L2 ventral horns travel to the ventral roots -> spinal nerves -> ventral rami -> white rami communicans -> sympathetic chain ganglia -> gray rami communicans -> ventral ramus to target
how are splanchnic nerves used in sympathetic signaling?
a preganglionic fiber moves through ventral ramus to root, to spinal nerve to ventral rami through white rami communicans to just PASS THROUGH the ganglion and exit through the greater, lesser,least and lumbar splanchnics to terminate in a collateral ganglion located adjacent to the main arterial branches in the abdominopelvic cavity
where does the greater splanchnic nerve originate?
T5-T9
where does the lesser splanchnic nerve originate?
T9/10 - T10/11
where does the least splanchnic nerve originate?
T12
where does the lumbar splanchnic nerve originate?
L1-L2
function of the splanchnic nerves?
provide visceral efferent and afferent sympathetic fibers to and from organs
what are the pelvic splanchnics?
S2-S4
pathway of parasympathetic division travel
preganglionic fibers in these nerves synapse on postganglionic neurons in ganglia that are on/near the target organ
what innervates lung structures and visceral pleura?
anterior and posterior pulmonary plexuses that originate from the sympathetic trunks and vagus nerves
what makes up the anterior and posterior pulmonary plexuses?
sympathetic trunks and vagus nerves
what role do the vagus nerves play in the innervation of the lungs?
they constrict the bronchioles (conserve energy), promote secretion
what role does the sympathetic trunks play in the innervation of the lungs?
they dilate the bronchioles, reduce secretion to increase max air exchange
what is the heart innervated by?
the cardiac plexus, made of sympathetic and parasympathetic innervations, regulates HR, force of contraction, CO
what contributes to the sympathetic innervation of the heart?
preganglionic fibers from upper 4-5 thoracic spinal cord levels that synapse in the cervical and upper thoracic chain ganglia
action of the sympathetic innervation on the heart?
increase HR, force of contraction
what contributes to the parasympathetic innervation of the heart?
vagus nerves
action of parasympathetic innervation of the heart?
decrease HR, reduce force of cardiac contraction and constricts the coronary arteries
where is the cardiac plexus located?
between the bifurcation of the trachea and the arch of the aorta
where is the anterior pulmonary plexus located?
between tracheal bifurcation and primary bronchus
where is the posterior pulmonary plexus located?
inferior to bifurcation and primary bronchus
borders of the posterior mediastinum
anteriorly: pericardium, postiorly: thoracic vertebra 5-12, inferiorly: diaphragm, laterally: parietal pleura/mediastinal pleura, superiorly: sternal angle/T4
location of cell bodies of preganglionic neurons of sympathetic system?
lateral horns/intermediolateral cell columns
what spinal cord segments associated with upper limbs and thoracic organs?
T1-T4
what spinal cord segments associated with innervation of organs in abdominal cavity/foregut
T5-T9
what nerves carry cardiac sympathetic efferent fibers from sympathetic ganglia to thoracic viscera and afferent fibers for pain?
cardiopulmonary splanchnic/thoracic visceral nerves
what nerve is responsible for parasympathetic innervation of the lungs?
vagus nerve
what nerve innervates the pericardium?
phrenic nerve
