Mediastinal anatomy Flashcards
What are the borders of the Mediastinal?
Superior border- superior thoracic aperture
Inferior border - Diaphragm
Anterior border - Sternum
Posterior border - 12 bodies of Thoracic Vertebrae.
lateral border - two borders (one on each side - mediastinal Parietal Pleura.
How is the mediastinum divided.
Divided into the superior and inferior mediastinum. Division (imaginary line from the Sternal angle to the middle of the and Intervertebral layer between the T4/T5 Thoracic vertebrae.
From the anterior to the posterior border name the structures in the superior mediastinum - in order?
Sternum - Thyroid gland - left and right brachiocephalic vein (which join to form ) Superior vena cava – Aortic Arch and great vessels (from right to left - brachiocephalic Trunk , the left common carotid artery and the left subclavian artery—– Trachea —- Oesophagus (all of these sit in the midline)
Left of the oesophagus is the Thoracic duct. Next to this the Left vagus nerve (thicker) , anterior to this is the left phrenic nerve (thinner) —– Sympathetic trunk (nerve on the lateral side of the
What nerve branches of the left vagus nerve ?
Left recurrent laryngeal nerve.
This hooks under the ligamentum arteriosum - a ligament (runs between the inferior surface of the aortic arch and the superior surface of the left pulmonary artery —remnant of the fetal ductus arteriosus.(connection btw pulmonary trunk and aorta)
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What are the components of the inferior mediastinum ?
- Anterior mediastinum ( in front of pericardium )—– consists of the paired Thoracic arteries , inferior section of thymus gland
- middle mediastinum - (within pericardium)——- superior and inferior vena cava, ascending aorta , heart , phrenic nerves.
Posterior mediastinum - (behind pericardium )
From the anterior to the posterior name the structures in the posterior mediastinum - in order?
Anterior - oesophagus , azygous vein, Thoracic duct and descending Aorta.
Left and right vagus nerve and sympathetic duct which have branches that eventually fuse to become individual nerves which descend into the Thorax behind the diaphragm - Thoracic Splanchnic nerves.
Where is the cardiac apex ?
at the 5th intercostal space on the mid clavicular line. This where the apex beat is felt.
What the brachiocephalic artery bifurcate into?
Right common carotid artery and the right subclavian artery,
What is a leaky and narrowed valve called?
narrowed - Stenosis
Leaky - regurgitation
Difference between right and left ventricular failure?
LVF - blood not pumped effectively out of lungs and round systemic circulation
Consquences
- Shortness of Breath
- Tiredness
- Orthopnoea (breathlessness when lying flat)
- Pulmonary odema - airspaces in lungs.
RVF - blood not pumped effectively in pulmonary circulation.
Consquences
-odema in the legs/feet
-raised jugular pulsation on clinical examination.
What disorders can affect heart function?
Ischaemia - not enough blood supplying myocardium via the coronary arteries.
- Infarction - obstruction of blood supply to myocardium e.g of the coronary arteries (can lead to death)
- heart rhythm disorders - heart is beating to fast or slow becoming inefficient.
Heart valve disorders (stenosis , regurgitation)
- Disease of myocardium- can be cause by systemic diseases or diseases of the heart muscle.
- Pericardial disease - constricts the heart - causes inefficient filling of ventricles.
Cardiac tamponade - bleeding in pericardium compressing the heart , preventing blood return to the heart. ( periacrdiocentosis - procedure performed to aspirate blood from the pericardial sac with large needle and syringe.
Where are the borders of the heart in terms of surface anatomy ?
Upper limits - gently slopes from the 2nd to 3rd costal cartilage (CC) - 1cm to right of Sternum and 2cm for the left.
Right lateral border - 1-2cm right of sternum from 3rd to 6th CC
Left lateral -from 2nd IC space to 5th joining the mid- clavicular line.
Inferior - 6th CC to 5th IC space.
Location of the Tricupsid valve ?
medially to the 4th IC space , just right of midline of sternum.
Location of the Pulmonary valve ?
At the 3rd interchonsternal joint ?
Location of the Mitral valve ?
At the 4th CC , 1-2cm from sternum. listen for it at the apex (5th IC)
