Oesophagus, heart and mediastinum exam Flashcards
Describe the blood supply and lymphatic drainage of the oesophagus
Arterial supply:
–> upper 1/3rd: Inferior thyroid artery (thyrocervical trunk)
–> middle 1/3rd: Branches of descending thoracic aorta
–> lower 1/3rd: Branches from left gastric artery, inferior phrenic artery
Venous drainage
–> Upper 1/3rd: inferior thyroid vein
–> Middle 1/3rd: Azygous vein
–> lower 1/3rd: oesophageal branches left gastric vein
Lymphatic drainage:
–> upper 1/3rd: deep cervical nodes
–> Middle 1/3rd: superior and posterior mediastinal nodes
–> lower 1/3rd: Left gastric nodes and coeliac plexus
Describe the musculature of the oesophagus
-Upper 1/3rd: striated
-MIddle 1/3rd: mixed
-Lower 1/3rd: smooth
What is the anatomical mechanism that normally prevents gastro-oesophageal reflux?
Lower oesophageal sphincter: functional sphincter which is a high pressure zone ~2-5cm
-Angle of his: oesophagus enters stomach at acute angle
-Phreno-oesophageal ligament which encircles gastro-oesophageal junction
-Prominent mucosal folds at gastro-oesophageal junction
-Increase in intra-abdominal pressure causes compression of abdominal part of oesophagus
What type of diaphragmatic hernias do you know of?
Congenital
-Bochdalek
-Morgagni
Aquired
Hiatus hernia
–> sliding
–> rolling
Risk factors for hiatus hernia
-Age related degeneration
Chronically raised intra-abdominal pressure
–> coughing
–> obesity
–> pregnancy
Why is a sliding hiatus hernia a risk factor for gastro-oesophageal reflux?
-Migration of LES into chest results in loss of high-pressure zone. This predisposes pt to GORD
What are the constrictions of the oesophagus?
Cricoid cartilage at C5/6 –> 15cm from incisors
Arch of aorta T4/5 –> 22.5cm from incisors
Left principal bronchus –> 27cm from incisors
Diaphragmatic hiatus T10/11 –> 40cm from incisors
ABCD:
-Arch of aorta
-left main bronchus
-Cricoid cartilage
-Diaphragm
What is the cell lining of oesophagus?
Stratified squamous
What is barrett’s oesophagus?
Columnar metaplasia with increased risk of developing adenocardinoma
What is achalasia?
-Oesophageal motility disorder involiving the smooth muscle layer of the oesophagus and LES. It is characterised by incomplete LES relaxation, increased LES tone and lack of peristalsis of the oesophagus
What is the microscopic picture of achalasia?
-Hypertrophied musculature with the abscence of a myenteric plexus
Course of oesophagus
-Originates at level of C6 (inferior border of cricoid cartilage)
-Runs in superior/posterior mediastinum
-Enters abdomen at diaphragmatic hiatus (T10)
-Abdominal part terminates by joining cardiac orifice of stomach at T11
How many cusps does the pulmonary valve have?
3
What is the vertebral level of the pulmonary valve?
T6
Where would you auscultate the valves?
-Pulmonary: 2nd ICS left parasternal edge
-Aortic: 2nd ICS right sternal edge
-Mitral: 5th ICS mid clavicular line
What are the tributaries of the azygous vein?
Right handed PM Loves Eating Burgers
-Right superior intercostal vein
-Hemiazygous and accessory hemiazygous
-Pericardial veins
-Mediastinal veins
-Lower right posterior intercostal veins
-esophageal veins
-Bronchial veins
What are the branches of the ascending aorta?
-Right and left coronary arteries arising from the aortic sinus opposite the aortic valve
also13, 19
What are the branches of the aortic arch?
-Brachiocephalic (right subclavian, right common carotid)
-Left common carotid
-Left subclavian
Describe subclavian steal syndrome
-Retrograde flow of blood down to the vertebral artery due to vertebral artery due to stenosis in the subclavian artery proximal to the vertebral artery
-This will lead to brainstem ischamemia on arm excercise
-symptoms include syncope, neurological deficit eg tinnitus, vascular insufficiency of arm
Describe thoracic outlet syndrome
-Compression of the neurovascular bundle (brachial plexus, subclavian artery) between the scalenus medius and scalenus anterior–> neurological and vascular symptoms in the arm
How on the skeleton where to put a chest tube
5th intercostal space mid axillary line
Why do you get bradycardia after chest tube insertion?
-Due to irritation of the vagus nerve
Thoracic inlet and mediastinum
What are the boundaries of the posterior mediastinum?
Anterior: pericardium
Posterior: T5-T12 vertebrae
On either side: mediastinal pleura
Floor: diaphragm
Roof: imaginary line extending from sternal angle (T4)
Contents superior mediastinum
PVTS Last BATTLE
Phrenic nerve
Vagus nerve
Thoracic ducts
Left recurrent laryngeal
Brachiocephalic vein
Aortic arch
Thymus
Trachea
Lymph node
Oesophagus
What are the contents of the posterior mediastinum?
on the DATE Vivian Slapped Larry
Descending thoracic aorta
Azygous/hemiazygous vein
Thoracic duct
Esophagus
Vagus nerve
Splanchnic nerves
Lymphatics
Vessels: thoracic part of descending aorta, azygous and hemiazygous veins
Nerves: Vagus + splanchnic nerves (arising from sympathetic trunk to supply viscera in thorax + abdomen)
Viscera: oesohpagus
Others: Lymph nodes + thoracic duc
Tributaries of azygous vein
Right handed PM Loves Eating Burgers
-Right superior intercostal vein
-Hemiazygous and accessory hemiazygous
-Pericardial veins
-Mediastinal veins
-Lower right posterior intercostal veins
-Oesophageal veins
-Bronchial veins
Contents of middle mediastinum
-Pericardium
-Heart
-Aortic root
-Arch of azygous vein
-Main bronchi
Where do preganglionic fibres of sympathetic trunk come from?
-Corresponding spinal nerves T1-L2
What connects the sympathetic trunk to the spinal nerves?
Preganglionic fibres from the spinal nerves and the sympathetic ganglia. Post ganglionic fibres then arise from the sympathetic ganglia and travel to target organs throughout the body.
How do sympathetic nerves leave the sympathetic chain?
Through the spinal nerves forming plexuses around blood vessels (cardiac and pulmonary plexuses, greater splanchnic nerve, lesser splanchnic nerve)
