Thorax: Mediastinum & Heart Flashcards
Where is the anterior mediastinum?
Extends from behind sternum to the pericardium
WHat is located in the anteiror mediastinum?
- Fat
- Lymph nodes
- Thymus (central)
- Located in the anterior/superior mediastinum, anteior to pericaridal sac, all the way up to thyroid glad.
- **Lymphoid organ **
- Growns until puberty then gradually diminished in size become mostly replaced by fat over time .
- Requires good **blood supply. **
Thymus Gland
From above the first rib, down to the sternal angel and T4 above the periocardial sac
Superior Mediastinum
What are the contents of the superior mediastinum?
Retrosternally
- Thymus
- Great veins; brachiocephalic vein & SVC
What are the contents of the superior mediastinum?
**Intermediatly **
- Aortic arch & great branches
- Nerves (vagus, phrenic, sympathetic branches)
What are the contents of the superior mediastinum?
Pre-vertebrally
- Trachea
- Esophagus
- Left reccurent laryngeal nerves
- Thoracic Duct
- Lymphnodes
Some thing is lodged in the trachea in the thoracic level of T2, peircing anteriorly, what will it puncture?
How about a posterior puncture?
Right or left common carotid arterys anteiror
The esophagus posteior
The conduit, lots running up and down.
RUns posterior.
T5- T12
Posterior Mediastinum
Content of the posterior mediastinum?
- Thoracic Descending aorta
- Thoracic Duct
- Primary Bronchi
- Azygous system
- Esophagus
- ANS/Spalachic nevers
- Vagus nerve (sympathetic in posteriro)
Located in the posterior mediastinum, prevertebrally.
Esophagus
WHat are the 3 retrosternal (most superficial layer) great veins of the mediastinum?
- Left brachiocephalic
- RIght brachiocephalic
- Superior Vena cava
Venous RETURN to heart
Formed by the union of the right and left brachiocephalic veins
Superior Vena Cava
Formed by union of left internal jugular and subclavian veins
Left Brachiocephalic Vein
Arm head vein
Formed by union of right internal jugular and subclavian veins
Right Brachiocephalic Vein
Arm head vein
2nd layer, behind venous system, takes oxygenated blood out of LV and to the rest of the body
Aorta; aortic arch,
Anterior= ascending
Posterior= descending
Arterial branch coming off the ascending aorta, to the right side.
Unpaired.
Brachiocephalic Artery (trunk) SINGULAR
Higher into the neck, thr brachiocephalic trunk splits into 1. and 2. ?
- Right subclavian artery
- RIght common carotid artery
2 arterys coming directly off of the aortic arch and going to the left side?
- Left common carotid
- Left Subclavian artery
Thick fiborous connecting running out from the aortic arch and attaching down to the left pulmonary trunk.
Important landmark
Ligamentum Arteriosum
Where in the aortic arch connections is most suseptible to anuresyms?
The transtion from the aortic arch to the left subclavian artery.
The ____ nerve brancnes out once it reaches the aortic arch, and one of its branches loops under the aorta and up becoming what nerve?
Left Vagus nerve -> loops under and up to become the **reccurent laryngeal nerve **
Location T4-T12 All posterior innercostal arterys come off this. Peirces the diaphram at the T12 at what? What name after?
Thoracic Aorta (descending aorta) ; aortic hiatus -> Abdominal aorta
venous drainage of the thoracic cavity, highly variable system.
Azygous System of Veins
Vein on the right side the returns blood to the heart via the SVC.
Recieves blood from posteiror innercostal veins, hemi, acs. hemi.
Comes up and over the lung and into the SVC
Azygous Vein
2 Veins on the **left side **the returns blood to the azygous vein.
- Hemiazygous Vein
- Acessory Hemiazyous vein
The left inferior intercostal veins return blood where?
Hemiazygous Vein
The left superior intercostal veins return blood where?
Acessory hemiazygous vein
If im at T3/T4 and I perforate the esophagus on the lateral right side what structure will also be cut?
Azygous vein!
Lymph vessel returning lymp to the blood.
L2-3 all the way up to dump into venous angel (left jugular trunk & left subclavian vein )
Runs up spinal collum.
Thoracic Duct
Attached to L2-L3, hold the lymphatic fluid coming from the digestive system. Travles upward through thoracic duct!
Cisterna Chyli
What veins recieve lymph fluid from the thoraci duct?
Venous Angle
Left jugular vein & Left subclavian vein
Originates from the base of the skull and travles down
On the left side:
* runs down the side common carotid and subclavian, goes over the arch of the aorta , branches out (reccurent larygeal nerve) and then continues down along the esophagus, forming a plexus, and once it goes through the esophageal hiatus, it becomes the anterior vagal trunk.
On the right side:
* Crosses of over right subclavian artery after it has branches of the brachiocephalic trunk, nerve branches and it then loops down under sub. artery and up into larynx (reccurent larygneal nerve) and continues down along the esophagus, forming a plexus, and once it goes through the esophageal hiatus, it becomes the posterior vagal trunk.
Vagus Nerve (10)
Path of the left Vagus Nerve
On the left side:
* runs down the side common carotid and left subclavian, goes over the arch of the aorta , branches out down and under the arch of the aorta and back up (reccurent larygeal nerve) and then also continues down to the esophageal hiatus as anterior vagal trunk .
Path of right vagus nerve
On the right side:
* Crosses over right subclavian artery after it has branched off the brachiocephalic trunk, nerve branches and it then loops down under right subclavian artery and up into larynx (reccurent larygneal nerve) and also continues down to enter abdomen through the esophageal hiatus as posterior caval trunk
From a lateral view
Where does the right phrenic nerve go?
Pass on top of pericardium TIGHTLY. Outside of fibrous layer. Provides **sensory to fiboruus pericaridum. **
RUns lateral to the vertebral to bodies, most posterior in throrax. T1-L2.
Splanchi nerves come off and run down into the abdomen.
Sympathetic Chain
Unique nerves that carry pre-ganglionic GVE (motor) signals to the abdominal viscera. And** GVA (sensory) **
Splanchnic nerves
Posterior to the trachea, descending.
Traverses both superior and posterior mediastinum
Esophagus
What 3 structures compress the esophagus as it descends?
- Aortic Arch
- Left Main bronchus
- DIaphram
An aortic arch aneurysm (ballon out of vessle) can push posteriorly and constrict what?
Compress the esophagus!
An impingment on the left bronchus can causes what?
Compression of the esophagus!
Stenosis of the esophagyeal hiatus can causes what?
Impingment of the esophagus