Blue Boxes III Flashcards
rib dislocation
Displacement of costal cartilage from sternum (sternocostal joint).
From impact.
Interchondral joint displacement can occur with false ribs (8, 9, 10) and may damage diaphragm or liver, while leaving a lump at site of displacement.
rip separation
Dislocation of costochondral junction between rib and anterior costal cartilage.
Causes rib to move superiorly over rib above.
intercostal nerve block
local anesthesia of intercostal space.
Anesthetic injection between paravertebral line and the area of required anesthesia.
Dermatome overlap requires 2+ contiguous intercostal nerves to be blocked to achieve complete loss of sensation.
pulmonary collapse
Normal lung remains distended even with open airways due to visceral pleura adhering to parietal pleura on inner surface of thoracic wall (negative intrapulmonary pressure).
Negative intrapulmonary pressure causes air to enter interpleural space if it is perforated. Surface tension between pleura will fail to hold lung in a distended state, causing collapse by its own elastic recoil (secondary atelectasis).
Collapsed lung will appear on radiography as a mediastinal shift toward affected side, with diaphragm elevation and narrowing of intercostal space.
hemothorax
caused by damage to an intercostal or internal thoracic vessel, or from internal lung hemorrhage.
pneumothorax
Caused by penetrating wound to parietal pleura, from rupture of a pulmonary lesion into the pleural cavity (bronchopulmonary fistula) or from fractured ribs tearing the visceral pleura.
hydrothorax
caused by pleural effusion
hemopneumothorax
can be seen by horizontal air-fluid interface on xray
thoracentesis
Insert needle into pleural cavity to sample fluid or remove blood/pus.
With pt upright, fluid accumulates in costodiaphragmatic recess (9th intercostal space).
Insert needle along midaxillary line, angled superiorly to avoid piercing diaphragmatic parietal pleura and diaphragm above liver.
chest tube
For draining severe hemothorax, pneumothorax, or hydrothorax.
Incision at 5th/6th intercostal space (nipple level) at midaxillary line for tube insertion.
Angle superiorly toward cervical pleura (cupola) for pneumothorax, or inferiorly (toward costodiaphragmatic recess for hydro/hemothorax.
lung auscultation/percussion
Auscultation will assess airflow through the tracheobronchial tree.
Percussion will show if the tissue is air-filled (resonant sound), fluid-filled (dull sound) or solid (flat sound).
“Base of lung” may refer to inferoposterior part of inferior lobe, auscultated in T10 intervertebral space on the posterior thoracic wall.
bronchoscopy
view down trachea to carina.
Carina can be distorted, posteriorly widened and immobilized by bronchiogenic carcinoma that has metastasized to tracheobronchial lymph nodes.
Aspirated objects tend to fall into right lung bc R bronchus is straighter, wider, more vertical.
Cough reflex
Mucous membrane covering carina causing choking/coughing when solid objects or fluid come into contact, assisting in bronchial expulsion.
mediastinal shifts
Transverse thoracic plane (divides superior/inferior mediastinum) does not shift with gravity, only the viscera do.
mediastinal shifts: supine
Viscera spread horizontally, pushing them superiorly.
Aortic arch superior to transverse thoracic plane.
Tracheal bifurcation inferior to transverse thoracic plane.
Central tendon of diaphragm lies at xiphisternal junction (T9)
mediastinal shifts: standing
Aortic arch transected by transverse thoracic plane.
Tracheal bifurcation inferior to transverse thoracic plane.
Central tendon of diaphragm lies at mid-xiphoid process (T9-10)
widening of mediastinum
Common from trauma causing hemorrhage after great vessel laceration or from malignant lymphoma enlarging mediastinal lymph nodes.
Congestive heart failure (venous return rate > cardiac output) can cause myocardial hypertrophy, showing an enlargement of the inferior mediastinum.
pericarditis
Inflammation to the pericardium causing chest pain, roughening of the serous pericardium causing a pericardial friction rub, audible on auscultation of the left sternal border.
Chronic inflammation can cause calcification or pericardial effusions (may cause cardiac tamponade) - non inflammatory effusions can resule from congestive heart failure (decreased cardiac output causes right cardiac hypertension
cardiac tamponade
Heart compression due to pericardial effusion limiting cardiac output. Hemopericardium can result in status post-MI or after cardiac surgery causes rapid compression leading to circulatory failure, jugular venous distension (blood backup from SVC).
Pneumothorax can dissect CT, causing pneumopericardium.
pericardiocentesis
Used to drain pericardial effusions to relieve cardiac tamponade.
Two methods of entry: (1) insert a needle thru 5th/6th intercostal space close to sternum with needle entering bare area made by cardiac notch of left lung.
(2) Insert a needle angled upwards thru infrasternal angle
valvular heart disease: Stenosis
valve does not open fully.
valvular heart disease: regurgitation
Valve does not close fully. Increases cardiac workload.
Reduces cardiac output.
Causes blood turbulence heart as murmurs and sometimes felt as thrills.
mitral valve prolapse/insufficiency
Flaps extend back to LA during systole, allowing blood to regurgitate back to LA during LV contraction
pulmonic valve stenosis
Valve cusps fuse forming a dome with a narrow opening, restricting RV outflow and causing RV hypertrophy
Infundibular pulmonary stenosis
Underdevelopment of conus arteriosus (conical ouch formed by the upper left angle to the right ventricle before the pulmonary trunk) causes restricted flow to pulmonary artery.
pulmonic valve incompetence
Valve lunules (edges of cusps) become inflexible, causing valvular insufficiency, allowing retrograde flow back to the RV during diastole.
aortic valve stenosis
Commonly caused by degenerative calcification or rheumatic fever.
Causes LV hypertrophy.
Seen age >60.
aortic valve insufficiency
Aortic regurgitation back to the LV causing a murmur and collapsing pulse (rapidly diminishing forcible pulse).
coronary artery disease
Coronary occlusion, resulting in any of the following:
acute MI
coronary atherosclerosis
angina pectoris
acute MI
Region of myocardium perfused by occluded coronary artery become infarcted, most commonly due to LAD stenosis, followed by RCA and Circumflex branch of the LCA.
coronary atherosclerosis
Lipid deposition of arterial intima.
Causes slow stenosis with compensatory expansion of collateral arteries (often insufficient during exercise) leading myocardial ischemia and MI
angina pectoris
Severe, constricting chest pain due to transient ischemia and MI that does not induce infarction.
Ischemia triggers limited anaerobic metabolism, causing lactic acid accumulation, that triggers pain response. Common with exercise, cold exposure, or stress.
Pain relieved by 1-2 min of rest or sublingual nitroglycerin to dilate coronary arteries.
Pain may radiate in T1/2/3 distributions.
CABG
Coronary Artery Bypass Graft.
Grafting of a vein (great saphenous) or redundant artery (radial, internal thoracic) from the aortic arch (or proximal to the stenosis) to a point distal to the coronary stenosis.
Use of the internal thoracic artery does not require it to be detached entirely, it can simply be surgically anastomosed distal to the stenosis.
coronary angioplasty
Percutaneous transluminal coronary angioplasty passes a catheter into the stenosed artery, inflating a balloon to flatten the plaque and stretch the vessel.
Thrombokinase can be injected to dissolve a thrombotic embolus.
After vessel dilation, a stent is placed to maintain luminal patency.
cardiac referred pain
Afferent pain fibers run centrally in the middle and inferior cervical branches and thoracic cardiac branches of the sympathetic trunk to T1-T5 (especially on left side).
Angina carried by lateral brachial, lateral antebrachial cutaneous nerves with t2-T3 intercostobrachial nerves because T1-T3 carries the visceral afferent fibers for the coronary arteries.
Visceral referred pain transmitted by visceral afferent fibers which accompany sympathetic fibers, felt in the regions of distribution covered by the spinal root into which they enter.
thoracic duct laceration
Thin walled, white/colorless alongside the azygous vein and feeding into the L venous angle commonly damaged during surgery in the posterior mediastinum.
Damage causes leakage of lymph/chyle into the thoracic cavity, causing chylothorax and requiring thoracentesis with possible ligation of the duct (rerouting flow to a point superior to ligature via the venous system).
acending aorta aneurysm
The aorta is only reinforced with a fibrous pericardium at the beginning of the arch. The acending region more proximal to the heart is weaker, thus the high pressure in aorta during systole may cause an aneurysm.
Commonly presents as chest pain radiating to the back, and may exert pressure on the trachea, esophagus, and recurrent laryngeal nerve causing dysphagia and dyspnea.
aortic corarctation
Stenosis of the aortic arch diminishing flow to the inferior parts of the body.
Commonly occurs at the ligamentum arteriosum, either before it (preductal coarctation) or after it (postductal coarctation).
postductal coarctation
Allows good collateral circulation to develop between aorta proximal and distal to the coarctation via the intercal thoracic a, which causes enlargement of this artery and the intercostal arteries (visible on radiograph, causing rib notching)
preductal coarctation
Congenital malformation that reduces flow to the lower part of the body, but does not develop good collateral circulation, causing poor lower body development and cyanosis.
probe-patent foramen ovale
small opening in adult fossa ovalis.
Often clinically insignificant.
(osteum secundum defect)
Cor trilocurlare biventriculatum
congenital absence of atrial septum
sinus venosus defect
improper development of septum secundum, leaving an opening above the fossa ovalis.
cor triloculare biatriatum
congenital absence of ventricular septum
retroesophageal right subclavian artery
Right subclavian originates proximal and inferior to the left subclavian off the aortic arch, crossing behind the esophagus, causing dysphagia.
persistent truncus arteriosus
Failure to form a trunoconal septum at all due to abnormal neural crest cell migration.
Includes ventricular septal defect (no membranous interventricular septum).
Causes mixing of oxygenated/deoxygenated blood.
transposition of the great vessels
Due to failure of the truncoconal septum to spiral.
Causes left ventricle to empty into pulmonary circulation and the right ventricle to empty into systemic circulation, causing cyanotic heart disease.
Not immediately fatal if there is mixing of blood thru patent foramen ovale or ductus arteriosus.
tetralogy of Fallot
Due to formation of truncoconal septum too far toward pulmonary (anterior) side of truncus arteriosus.
1) pulmonary stenosis: due to decreased size of pulmonary trunk, with enlarged aorta.
2) Ventricular septal defect: misalignment of truncoconal septum prevents fusion with muscular ventricular septum prevents fusion with the muscular ventricular septum, so no membranous ventricular septum forms.
3) Overriding aorta: aorta extends over right ventricle from the left ventricle.
4) Right ventricular hypertrophy: due to excess blood sent to RV from the higher pressure LV system.
The deoxygenated blood erroneously pumped into aorta from RV causes severe cyanosis.
Variations of great a. (anomalies of branches off arch of aorta)
branches of arch of aorta
- could have L comm carotid originating of brachiocephalic trunk
- could have no formation of brachiocephalic trunk –> each of 4 a.s (R/L comm. carotid and subclavian a/) originate independently from arch of aorta
- could have L vertebral a. originating from arch of aorta
- could have retroesophageal R subclavian a. as last branch of arch of aorta (crosses posterior to esophagus to reach R upper limb –> dysphagia)
- could have an accessory a. to thyroid gland (thyroid ima a.) arising from arch of aorta or brachiocephalic a.
Variations of great a. (anomalies of arch of aorta)
- sometimes arch curves over the root of the right lung and passes inferiorly on the right side, forming a right arch of the aorta
- arch could pass over root of R lung, pass posterior to esophagus to reach usual position on L.
- double arch (vascular ring around esophagus and trachea)
