What is the anatomy of the mediastinum in relation to intravascular intervention Flashcards
What is dysphagia?
Difficulty swallowing
Where is the mediastinum?
area between the lungs
What are the borders of the mediastinum?
o superior: thoracic inlet (bounded by ribs 1, T1 vertebrae & jugular notch)
o anterior: transverse thoracic plane (between T4/5 intervertebral disc) sternum and fibrous pericardium
o posterior: posterior heart thoracic vertebrae between T4/5
What is the thymus?
gland/lymphoid organ producing T lymphocyte in childhood- involutes and becomes replaced by adipose tissue after puberty
Where is the thymus?
Anterior mediastinum
What does the middle mediastinum contain?
o pericardium o heart o parts of the great vessels that connect with the heart; -inferior part of SVC -superior part of IVC -pulmonary trunk and pulmonary arteries -pulmonary veins -ascending aorta
What does the posterior mediastinum contain?
o the azygous vein: conveys blood from the intercostal veins to the SVC
o sympathetic trunks/chains
o the thoracic duct: carries lymph to venous angle
o vagus nerves
o trachea and 2 main bronchi: the trachea bifurcates at the level of the sternal angle so is in the superior mediastinum
o thoracic aorta: only the thoracic part of the aorta is in the posterior mediastinum
Where do the intercostal veins drain into?
posteriorly into the azygous vein
What are the mediastinal branches from aorta?
o coronary arteries o brachiocephalic trunk o left common carotid o left subclavian artery o bilateral posterior intercostal arteries (one per space)
What are the anterior branches of the aorta?
- bronchial arteries (arterial blood for lung tissue
- oesophageal arteries
- mediastinal arteries
- pericardial arteries
- phrenic arteries
What is the aortic hiatus?
Opening in the diaphragm
Where does the right lymphatic duct drain?
Drains the right side of the head, right arm, right thorax into the right venous angle
Where does the thoracic duct drain?
Drains left head, left thorax and lower body into left venous angle
What does the trachea play a key role in?
Speech
What is the surface anatomy of the left venous angle?
Left sternoclavicular joint
What is the cysternae chyli?
Swollen part of the thoracic duct in abdomen
What is the path of the right phrenic nerve?
passes through the diaphragm with the IVC to supply the diaphragm from the inferior aspect
What is the path of the left phrenic nerve?
pierces through the left dome of the diaphragm to supply it from the inferior aspect
What is the ligamentum arteiosum?
remnant of the ductus arteriosus
Describe the anatomy of the superior mediastinum from anterior to posterior
- brachiocephalic veins & SVC
- arch of aorta & the origin of its 3 branches
- trachea
- oesophagus
- thoracic duct
Describe the anatomy of the superior mediastinum from lateral to medial?
- phrenic nerves
- vagus nerves
- recurrent laryngeal nerves
What are the central veins?
large veins close to the heart such that the pressure is said to be approximately the pressure in the RA
How can we access the central veins?
o internal jugular vein o brachiocephalic vein o SVC o right atrium o inferior vena cava o iliac veins o femoral veins
What the the JVP like in the anatomical position?
the internal jugular veins contain little blood and are collapsed flat
What causes the double pulsation?
atrial contraction then filling of the right atrium against a closed tricuspid valve causes a double pulsation pressure wave conducted in a retrograde direction into the central veins that can be observed in the internal jugular vein
What is the path of the left and right laryngeal nerve?
Right recurrent laryngeal nerve: hooks under the right subclavian artery: does not enter the chest
left recurrent laryngeal nerve: hooks under the arch of the aorts: does enter chest
What are the phrenic nerves formed from?
combined anterior rami of cervical spinal nerves 3. 4 and 5
What is the function of the phrenic nerves?
-somatic motor to diaphragm
-somatic sensory to;
o mediastinal parietal pleura
o fibrous pericardium
o diaphragmatic parietal pleura
o diaphragmatic parietal peritoneum
What cranial nerve is known as vagus?
X
What does the vagus nerve contain?
o somatic sensory nerves for the palate, laryngopharynx and larynx
o somatic motor nerves for the pharynx and larynx
o autonomic parasympathetic nerves for the thoracic and abdominal organs
What are recurrent laryngeal nerves branches of?
branches of the vagus nerve that supply the pharynx and larynx
What do the vagus nerves contain after they give off their recurrent laryngeal branches?
Only parasympathetic efferents
How does pain become referred from the diaphragm?
1) irritates the parietal peritoneum lining the inferior surface of the diaphragm, which is supplied by the phrenic nerve (C3, 4, 5)
2) the supraclavicular nerves (C3, 4) supply the dermatomes over the shoulder tip and enter the spinal cord at the same levels as the phrenic nerve
3) but the brain ‘refers’ the pain to the more superficial structure, the
What does the cephalic vein supply?
superficial vein of the upper limb
Where is the pulse in the neck?
-bifurcation of the common carotid artery (also site for auscultating carotid bruits)
o anterior to sternocleido-mastoid muscle at level of superior border of thyroid cartilage
Where is the brachial pulse located?
o medial to the biceps brachii tendon in the cubital fossa
Where is the radial pulse located?
o lateral to the tendon of the flexor carpi radialis
Where is the femoral pulse located?
o inferior to midpoint of inguinal ligament
Where is the popliteal pulse located?
o in popliteal fossa (immediately posterior to knee joint)
Where is the posterior tibial pulse located?
o between the posterior border of the medial malleolus and the Achilles tendon
Where is the dorsalis pedis pulse located?
o medial to tendon of the extensor halicus longus on the dorsum of the foot
What interventions occur via the radial artery?
cannulation for arterial blood pressure monitor/ABG sampling
What interventions occur via the femoral artery?
intravascular interventions
What interventions occur via the subclavian artery?
insertion of cardiac pacing wire under ultrasound guidance
What interventions occur via the femoral vein?
insertion of central lines and intravascular interventions
What interventions occur via the jugular vein?
insertion of central line under ultrasound guidance
