Lungs And Mediastinum Flashcards
Thoracic cavity contents
. 2 pleural sacs and mediastinum
. Pleural sacs: closed serous sacs that contain lungs and pleural cavities
. Mediastinum: central compartment containing most remaining thoracic structures
Post. Thoracic wall
. Includes thoracic vertebral bodies, sympathetic trunks and intercostal spaces
. Related to mediastinal structures but not part of mediastinum
Mediastinum boundaries
. Sup: sup. Thoracic aperture . Inf: diaphragm . Sternum ant. . Thoracic vertebral bodies post. . Lat: R/L pleural sacs
Superior mediastinum
. Btw sup. Thoracic aperture and transverse thoracic plane
. Oblique plane through sternal angle and T4-5 disc
. Contains thymus, great veins, aortic arch w/ branches, vagus, and phrenic nn., trachea, esophagus, thoracic duct
Inferior mediastinum
. Extends inf. From transverse thoracic plane to diaphragm
. Subdivided into ant., middle, and post. Mediastinum
Anterior mediastinum
. Btw. Sternal body and pericardial sac
. Contains CT, fat, and lymph nodes
Middle mediastinum
. Pericardial sac and contents
. Contains pericardium, heart, root of great vessels, phrenic nerves
Posterior mediastinum
. Btw pericardial sac and vertebral column
. Contains esophagus, thoracic duct, descending aorta and branches, and a yoga venous system
T/F mediastinum anatomical conduit for structures traveling btw head, neck, thorax, and abdomen
T
Longitudinal structures generally moves from ___ mediastinum to ___ mediastinum
. Superior
. Posterior or middle
Mobility of viscera in mediastinum
, lie one vertebra higher in supine position
. Lie lower during inspiration than expiration
Thymus
. Lymphoid organ
. Post. To sternum
. Products T-lymphocytes
. Large in youth, replaced by fatty CT in adults
Great veins
. Drain head, neck, and upper extremities
. Brachiocephalic vv. formed by union of internal jugular and subclavian vv.
. Sup. Vena cava: formed by union of R/L brachiocephalic vv., terminates in middle mediastinum
R versus L brachiocephalic vv. Pathway
R: descends vertical and is shorter
L: courses obliquely ant. To aortic arch and it’s branches
Aortic arch
. Direct continuation of ascending aorta
. Sup. To transverse thoracic plane
. Courses posteriorly and to the left
. Gives 3 branches (brachiocephalic trunk, left common carotid, and left subclavian a.)
. Connected to L Pulmonary a. By ligamentum arteriosum (remnant of fetal ductus arteriosus)
Brachiocephalic trunk divides to form ____
. R common carotid
. R subclavian aa.
Aortic dissection
. Tear in aortic intima permits formation of subintimal hematoma
. Usually on ascending aorta or aortic arch
. Rupture assoc. w/ abrupt onset of severe chest and back pain and is frequently fatal
Trachea
. Membranous tube extending from larynx to level of T4-5 intervertebral disc
. Terminates by bifurcation into R/L primary bronchi marked by carina (keel-shaped)
. C-shaped cartilages that are deficient post. To permit food
Esophagus
. Continuous btw sup. And post. Mediastinum
. Musculomembranous tube connecting pharynx w/ stomach
. Immediately post. To trachea and ant. To vertebral bodies in sup. Mediastinum
. Immediately post. To pericardium and L atrium in post. mediastinum
Dysphagia
. Difficulty swallowing
. Can be caused by enlargement of mediastinal lymph nodes or hypertrophy of L atrium
Thoracic duct
. Enters thorax via aortic hiatus and drains into venous system at junction of L subclavian and internal jugular vv.
. Lies lat. to esophagus and post. To aortic arch in sup. Mediastinum
. Lies an. Vertebral column, btw azygos v. And descending aorta, and post. To esophagus in the post. Mediastinum
Structures restricted to post. Mediastinum
. Descending aorta
. Azygos system
Descending aorta and branches
. Continuation of aortic arch
. Descends on left side of vertebral column
. Branches: bronchial aa (bronchial tree and lungs), esophageal aa., sup. Phrenic aa. (Diaphragm), and post. Intercostal aa. ( to intercostal spaces and thoracoabdominal wall, right post. Intercostal cross ant. To vertebral bodies)
Coarctation of aorta
. Distal to attachment of ligamentum arteriosum postductal)
. Collateral circulation can develop via subclavian, internal thoracic, ant. And post. Intercostal aa. To maintain blood flow through descending aorta
Azygos system
. Venous networks draining thoracoabdominal wall and mediastinal viscera
Azygos v.
. Vertical venous channel that ascends on right of vertebral column
. Arch of azygos passes anteriorly sup. To root of R lung to drain into sup. Vena vena at T4 vertebral level
. Communicates w/ inf. Vena cava inf.
. Receives R sup. Intercostal v and all other post. Intercostal vv. Except 1st post. Intercostal v.
Right sup. Intercostal vein
. Unions of post. Intercostal vv. 2-4
Where does 1st post. Intercostal v. Drains to ___
right brachiocephalic v.
Hemiazygos and accessory hemiazygos vv.
. Vertical venous channels lying left of vertebral column
. Hemiazygos v.: receives post. Intercostal vv. 9-12 on the left then crosses ant. To vertebral bodies to drain into azygos v.
. Accessory: receives post. Intercostal 5-8 before draining into hemiazygos v. W/ azygos v.
1st post. Intercostal and sup. Intercostal v. On left drain directly to ____
Brachiocephalic v.
Superior to diaphragm from thoracic duct receives ____
. All structure inf. To diaphragm
. Post. Intercostal lymph vessels form post. Thoracic wall
. Lymph trunks from left: jugular lymph trunks (drains head and neck), subclavian trunk (drains upper limb), and bronchomediastinal trunk (drains lung and bronchial tree, mediastinum, and ant. Thoracic wall)
Right lymphatic duct
. Receives the right bronchomediastinal trunk draining lung and bronchial tree, mediastinum, and ant, thoracic wall on right
Chylothorax
Lymph accumulation in mediastinum/pleural cavity from thoracic duct damage
. Treatment: Ligate thoracic duct
Phrenic n.
. From C3-5 vnteral rami
. Provides motor and sensory innervation to diaphragm
. sensory innervation to pericardium and parietal pleura
Phrenic n. Pathway in sup. Mediastinum
. L phrenic n. Courses inferiorly post. To L brachiocephalic v. And ant. To aortic arch
. Right phrenic n. Lies lat. to R brachiocephalic v. And sup. Vena cava
Phrenic n. Pathway In inf. Medianstinum
. Lie btw pericardium and mediastinal pleura and ant. To lung roots
Vagus n.
. Provides presynaptic parasympathetic fibers to thoracic and abdominal viscera and motor and sensory innervation to larynx
Left vagus n.
. Courses ant. And lat. to arch of aorta in sup. Mediastinum
. Left recurrent laryngeal n. Lips around aortic arch near ligamentum arteriosum and ascends lat. to trachea
. Descends post. To root of lung and lat. to descending aorta and esophagus in post. Mediastinum before esophageal plexus
Persistent hoarseness from compression of L recurrent laryngeal n. Is warning sign for ____
Aortic aneurysms/ dissection
. Metastatic carcinoma of lung
. Mediastinal lymphoma
Right vagus n.
. R recurrent laryngeal n. Arises in root of neck and loops around R subclavian a.
. Descends post. To great veins and medial to arch of azygos v. In sup. Mediastinum
. Lies post. To root of lung and lat. to esophagus in post. Mediastinum before joining esophageal plexus
Cardiac and pulmonary branches of R/L vagus nn. Contribute to ____
Cardiac and pulmonary autonomic plexuses
Esophageal plexus and vagal trunks
. Fibers of r/L vagus nn. Join esophageal plexus
. Fibers reassemble to form ant. And post. Vagal trunks that accompany esophagus through esophageal hiatus
Anterior vagal trunk
Contains fibers from L vagus n.
Posterior vagal trunk
. Contains fibers rom right vagus n.
Sympathetic trunk (chain)
. 1st thoracic sympathetic ganglion fuses w/ inf. Cervical ganglion to form stellate ganglion
. Trunks lie lat. to vertebral bodies and ant. To necks of ribs
. Contains cell bodies of postsynaptic sympathetic neurons
Thoracic branches of sympathetic chain and pathways
. Cardiac branches: postsynaptic sympathetic fibers pass medially to joint cardiac and pulmonary plexuses
. Esophageal branches: join esophageal plexus
. Thoracic splanchnic nn.: carry presynaptic fibers that synapse on prevertebral ganglia in abdomen
Greater splanchnic nn.
Roots from T5-9 ganglia
Lesser splanchnic nn.
Roots from T10-11 ganglia
Least splanchnic n.
From T12 ganglion
Visceral afferent fibers supplying thoracic structure follow ______ pathways
Sympathetic and parasympathetic
Sympathetic associated visceral afferents
Convey pain sensations from the heart and other thoracic and abdominal viscera
Parasympathetic associated visceral afferent
. Convey sensation from bronchial tree (cough reflex), unconscious sensations related to homeostasis, and sensations of nausea
Pleural sac
. Visceral pleura and parietal pleura
Visceral pleura
. Inseparable from surface of lung and extending into fissures
. Innervated by visceral afferent and insensitive to pain
Parietal pleura
. Lines thoracic wall
. Contains costal pleura (contacts ribs and intercostal muscles), diaphragmatic pleura (contacts sup. Surface of diaphragm), mediastinal pleura (contacts structures of mediastinum), and cervical pleura (dome extending through thoracic inlet sup. To 1st rib)
. Supplied by somatic afferent fibers carried by intercostal and phrenic nn. And highly sensitive to pain
Pain in costal pleura and peripheral portions of diaphragmatic pleura referred to _____
Thoracoabdominal wal
Pain in mediastinal pleura and central portion of diaphragmatic pleura os referred to ____
Lower neck and shoulder
Pleural cavity
. Closed potential space btw visceral and parietal layers
. Contains thin layer serous fluid that acts as lubricant and facilitates free movement of lungs
. Lungs NOT in pleural cavities
Pleuritis/pleurisy
. Inflammation of pleura
. Roughens pleural surfaces creating friction on respiration that is a subtle as pleural fremitis (rub)
. Can lead to pleural effusion or formation of pleural adhesions
Pleural reflections
. Regions of transition btw different portions of parietal pleura
. Lines of pleural reflection mark boundaries of pleural sac
Sternal line
. Marks ant. Reflection of costal pleura to mediastinal pleura
. Left sternal line deviates to left at level of 5th intercostal space leaving pericardial sac ind I react contact w/ ant. Thoracic wall
Pericardiocentesis
. Needle inserted into 5th intercostal space
. Passes to bare area of pericardium w/o encountering parietal pleura
Costal line
. Marks reflection of costal pleura to diaphragmatic pleura and inf. Extend of pleural sac
. Slopes inf. And post.
. Base of lung 2 ribs sup. To costal line
Midclavicular line
Located at level of 8th rib
Midaxillary line
10 rib level
Midscapular line
12th rib level
Pleural recesses
. Region of contact btw layers of parietal pleura at sites of pleural reflection
. Potential spaces that accommodate lung expansion
. Costodiaphragmatic and costomediastinal recesses
Costodiaphragmatic recess
. Lies btw costal and diaphragmatic pleura
. Most inf. Point in pleural cavity
. Frequent site of fluid accumulation
Costomediastinal recess
Btw costal and mediastinal pleura, adjacent and post. To sternum
Pleurocentesis
. Draw off fluid in costodiaphragmatic space
Lung surfaces
. Base: rests of sup. Surface of diaphragm
. Apex: extends into root of neck sup. To 1st rib
. Costal surface: post. And lat.
. Mediastinal: bears impressions of mediastinal structures
Right lung structure
. Shorter, broader, and heavier than left lung
. 3 lobes
. Horizontal and oblique fissure
Left lung structure
. Taller and narrower than right lung . 2 lobes . Oblique fissure . Cardiac notch: accommodates heart . Lingula: tongue-like projection of sup. Lobe just inf. To cardiac notch, corresponds t middle lobe of right lung
Hilus
Indentation on mediastinal surface that transmits structures connecting lung to mediastinum
Root of lung
. Structures that connect lung to mediastinum
. Primary bronchus, pulmonary a. And vv, bronchial aa., vv., nn., and lymph
. Pleural sleeve (encloses root structures)
. Pulmonary ligament: bilaminar fold extending inf. From root of lung
Anthracosis
. Inhaled carbon particles that can’t be cleared from lungs and accumulate in CT and lymph nodes
Coal worker’s pneumoconiosis/black lung
. Causes by extended environmental or occupational exposure leads to inflammation, fibrosis, and severely diminished lung function
Primary bronchi
. Terminal branches of trachea
. R side is shorter, broader and more vertically oriented than the left
Aspirated objects more likely to pass into which lung?
Right lung
Secondary (lobar) bronchi
. Begins at hilus
. Supplies single lobe
Tertiary (segmental) bronchi
. W/in lung tissue
Bronchopulmonary segment
. Pyramidal segment of lung tissue supplied by single tertiary (segmental) bronchus
. Small anatomically and functionally self-contained unit of lung tissue
. Separated from adjacent segments CT septa
. Supplied by tertiary branches of pulmonary aa.
Lung volume reduction surgery
Diseased lung segments respected to improve function of healthy segments
Pulmonary vessels
. Carry deoxygenated blood to lungs and return oxygenated blood to heart.
Pulmonary aa.
. Terminal branches of pulmonary trunk
. Ant. And sup. To bronchi at hilus
. Following branching of bronchial tree
. Tertiary artery branches are intrasegmental and supplies single segment w/ no arterial anastomosis btw adjacent segments
Pulmonary embolism
. Obstruction of pulmonary arteries
. Causes interruption of pulmonary perfusion and acute respiratory distress
. Caused by blood clots, bacteria, fat globules, or gas bubbles in bloodstream
Pulmonary veins
. 2 per side (sup. And inf)
. Located ant. And inf. To bronchi at the hilus
. W/in lung tributaries of pulmonary veins course independently of arteries
. Individual bronchopulmonary segments drained by multiple pulmonary vein tributaries whose courses are intersegmental
Bronchial vessels
. Supply CT of lungs and conducting portions of bronchial tree
. Bronchial aa: direct branches fo descending aorta that follow bronchial tree branching
. Bronchial vv: drain to azygos vein system where blood is distributed by bronchial aa. Returns via pulmonary vein system
. Veins are smaller than bronchial aa.
Lymphatic drainage of lungs
. Follows bronchial tree
. Intrapulmonary lymph nodes drain to bronchopulmonary nodes at hilus of lung
. Bronchopulmonary nodes drain to tracheobronchial nodes located sup. And inf. To bifurcation of trachea
Inf. Tracheobronchial lymph nodes
. Sentinel nodes
. Enlargement dur to infection, lymphoma, or tumor metastasis can produce a deviation of carina that is visible in bronchoscopy
Innervation of lungs and bronchial tree
. Ant, and post. Pulmonary plexuses
. Surround bifurcation of trachea and extend laterally btw layers of pulmonary ligaments
Sympathetic innervation of lungs and bronchial tree
. Inhibit smooth muscle and glands of bronchial tree
. Leads to bronchodilation, reduced secretion
. Stimulate smooth muscle in pulmonary vessels causing vasoconstriction
Parasympathetic stimulation in lungs and bronchial tree
. Stimulate smooth muscles and glands of bronchial tree causes bronchoconstriction and inc. secretion
. Inhibits smooth muscle in pulmonary vessels causing vasodilation
Visceral afferent fibers in lungs and bronchial tree
. Vagus n. To bronchial mucosa (cough reflex), bronchial tree (monitor bronchoconstriction), and pulmonary vessels (chemo/baroreceptors)
. Convey sensations from bronchial tree and visceral pleura (sympathetic)
Pulmonary ventilation
. Lung inflation maintained by physical forces that resist the natural tendency of elastic lung tissue to recoil (collapse)
. Surface tension of serous fluid and neg. pressure w/in pleural cavity maintain contact btw visceral pleura and parietal pleura
Pneumothorax
. Air in pleural cavity causing lung collapse
Ope pneumothorax
. Sucking chest wound
. Occurs when respiratory movements cause air to rush in and out of thorax via open wound
Tension pneumothorax
. Tissue flap admits air but prevents escape
. Air in thorax displaces and compresses mediastinum and interferes w/ venous return to the heart causing jugular vein distension and tracheal shift toward the uninsured side
