Normal Lung Anatomy Flashcards
Tracheal rings are completed posteriorly by a flat band of muscle and connective tissue called
Posterior tracheal membrane
Left lateral wall of the distal trachea is indented by
Transverse portion of aortic arch
Length of trachea im adults
12 cm
Normal coronal diameter of trachea in men
25 mm
Normal coronal diameter of trachea in women
21 mm
Normal coronal to sagittal diameter ratio of trachea
0.6:1.0
Narrowing of the coronal diameter of trachea is termed _____ seen in patients with chronic obstructive pulmonary disease
Saber sheath trachea
Superior limit of trachea
Cricoid cartilage
Inferior border of trachea
Main bronchi
Interface of the rigt upper lobe with the right lateral tracheal wall is called
Right paratracheal stripe
The right paratracheal stripe should not exceed ____ in thickness
4mm
Tracheoesophageal stripe should not exceed ____mm
5mm
Thickening of tracheoesophageal stripe is commonly seen with
Esophageal carcinoma
Bronchus with more obtuse angle with the long axis of trachea
Right
Longer bronchus with length of 5cm
Left
Short bronchus with length of 2.2 cm
Right
1-3 mm airways are called
Bronchioles
Bronchioles bearing alveoli on their walls are termed
Respiratory bronchioles
The airway just before the first respiratory bronchiole is the
Terminal bronchiole
Smallest bronchiole without respiratory exchange structures
Terminal bronchiole
In average, total of ____ to _____ generations are found between the trachea and alveoli
21-25
Invaginations of the visceral pleura. Divides the lungs
Interlobar fissure
Upper lobe bronchus and its artery arise from _____, branch into 3 segmental branches: anterior, apical and posterior
Truncus anterior
Middle lobe bronchus arises from the
Intermediate bronchus
Blood supply of the middle lobe is from
Branch of right interlobar pulmonary artery
Right lower lobe is supplied by the RLL bronchus and _____
pulmonary artery
Gas exchanging units of the lung
Alveolar ducts and alveolar sacs
Minor fissure projects at what rib level
Right 4th rib
Most common accessory fissure that is found in approx 10-20 % of individuals
Inferior accessory fissure
Invagination of the right apical pleura by the azygos vein
Azygos fissure
Separates the superior segment from the basal segments of the lower lobe
Superior accessory fissure
Sheet of connective tissue that extends from the hilum superiorly to a level at or just above the hemidiaphragm. Contains inferior pulmonary vein superiorly and a variable number of lymph nodes
Inferior pulmonary ligament
Pulmonary arteries arises from the
Right ventricle
Direct continuation of the main pulmonary artery
Left pulmonary artery
Hypoarterial
Left hilar bronchus
Eparterial
Right main bronchus
Primary nutrient vessels of the lung
Bronchial arteries
Supplies bronchial walls to the level of terminal bronchioles, tracheal wall, middle third of the esophagus, visceral pleura, mediastinal lymph nodes, vagus nerve, pericardium and thymus
Bronchial arteries
Bronchial arteries usually arise from the
Proximal descending thoracic aorta at the level of carina
Arises from the posterolateral wall of aorta in common with an intercostal artery as an intercostobronchial trunk
Right bronchial artery
Arise individually from the anterolateral aorta or rarely from an intercostal artery
Left bronchial arteries
Approximately 2/3 of the blood from bronchial arterial system returns to the pulmonary venous system via
Bronchial veins
Arise within the interlobular septa from the alveolar and visceral pleural capillaries
Pulmonary veins
2 major lymphatic pathways in the lung and pleura
Visceral pleural lymphatics
Parenchymal lymphatics
The perivenous lymphatics and their surrounding connective tissue when distended by fluid account for the radiographic appearance ofs
Kerley A lines
Scaffolding of the lung and as such provides support for the airways and pulmonary vessels
Pulmonary interstitium
Interstitial compartment that extends from the mediastinum and envelopes the bronchovascular bundles is termed the
Axial interstitium
The axial fiber system continues distally as the _____ along with the arterioles, capillaries and bronchioles to provide support for the air-exchanging portions of the lung
Centrilobular interstitium
Parts of the peripheral interstitium which divides secondary pulmonary
Subpleural interstitium and interlobulat septa
Edema involving the axial interstitium is recognized radiographically as
Peribronchial cuffing
Radiographically, edema of the peripheral and subpleural interstitum accounts for _____ lines or interlobular lines on HRCT and thickened fissures on chest radiograph
Kerley B lines
The upper ribs have smooth superior and inferior cortical margins while the middle and lower ribs have flanged inferior cortices where the ______ run
Intercostal neurovascular bundles
Cervical ribs are identified in 2% of individuals and may be associated with symptoms of
Thoracic outlet syndrome
Reflects contact of the anterosuperior aspect of the upper lobes
Retrosternal airspace
On frontal radiographs, the _______ line is seen as a thin vertical line that overlies the thoracic spine. It is the inferior extension of upper lobe reflections off the innominate veins
Anterior junction line
Radiolucent region representing contact of the posterosuperior portions of the upper lobes
Retrotracheal triangle
Vertically oriented in the midline that extends from upper thoracic spine to level of azygos and aortic arches
Posterior junction line
Convexity of the superior third of the azygoesophageal recess interface should suggest
Subcarinal lymph node enlargement or mass
The azygoesophageal recess, while normally straight or concave, the middle 3rd may have slight rightward convexity at the level of
Right inferior pulmonary veins
Or as a result of the confluence of right pulmonary veins or right border of left atrium
Left atrial dilatation will enlarge and laterally displace this interface, producing a double-density interface composed of right lateral borders of both right and left atria
Azygoesophageal recess
Convexity of the inferior third of the ______ recess is most commonly due to a sliding hiatal hernia
Azygoesophageal recess
Straight, vertical interface extending the length of the right hemithorax and represents contact of the right lung with a small amount of tissue lateral to the thoracic spine
Paraspinal interface
Individuals with pectus excavatum have leftward cardiac displacement and may not demonstrate the _____ interface
Paraspinal
In the uppermost portion of the left mediastinum, one or more interfaces may be recognized cephalad to the aortic arch. The interface most often visualized is the
Subclavian artery
Aortic nipple represents the _____ vein as it arches anteriorly from its paraspinal position around the aortic arch to drain into posterior aspect of left innominate vein
Superior intercostal vein
Aortic nipple normally measures
<5mm
This interface enlarges with elevation of right atrial pressure or with congenital or acquired obstruction of venous return to the right heart
Aortic arch
Immediately inferior to the aortic arch, the left upper lobe contacts the mediastinum to produce the ______ interface
Aortopulmonary window
Immediately inferior to the aortopulmonary window is the left lateral border of the _____ artery
Main pulmonary artery
Enlargement of this interface/structure is seen in idiopathic condition in young women, as a result of post stenotic dilatation in valvular pulmonic stenosis, left to right intracardiac shunts
Main pulmonary artery
Reflection of left lower lobe with the esophagus anterior to the descending aorta, extending vertically from the undersurface of the aortic knob
Preaortic recess interface
Represents the reflection of the left lung off the paraspinal soft tissues, which largely consist of fat but also contain the sympathetic chain, proximal intercostal vessels, intercostal lymph nodes and hemiazygos and accessory hemiazygos veins
Left paraspinal interface
Etched in black (negative Mach effect)
Preaortic recess
Etched in white (postitive Mach effect)
Left paraspinal interface
Neurogenic tumors, hematoma, paraspinal abscess, lipomatosis and medial pleural effusion can cause lateral displacement of this interface
Left paraspinal interface
Forms a concave interface immediately below the MPA. Straigtening or convexity of this interface used to be seen commonly in rheumatic mitral valve disease but may be seen in patients with left atrial enlargement of any cause
Left atrial appendage
Comprises most of the left heart border
Left ventricle
_______ fat pad is usually unilateral or more prominent on the left and is most often seen in obese patients and those on corticosteroids
Epipericardial fat pad
Apex of the right hemidiaphragm typically lies at the level of ____ rib
6th anterior rib
Bordered by the posterior border of trachea/esophagus, anterior border of spine and top of aortic arch
Retrotracheal (or Raider) triangle
Inferiorly the left lung may be excluded from contracting the anteromedial chest wall by a round or triangular opacity which represents the cardiac apex and adjacent extrapleural fat. This impression on the anterior surface of the lingular has been termed
Cardiac incisura
Represent pericardial layers between the epicardial and pericardial fat. Nodularity or thickness >2.0 mm suggests disease or effusion
Anterior pericardium
More vertically oriented lung fissure
Left major fissure
Narrow, vertically oriented structure that resides between the medial parieral pleural layers of the lungs. Contains central cardiovascular, tracheobronchual structures and esophagus enveloped in fat with intermixed lymph nodes
Mediastinum
Contents of thoracic inlet
Thymus Confluence of right and left IJV and subclavian veins Right and left carotid arteries Right and left subclavian arteries Trachea Esophagus Prevertebral fascia Phrenic, vagus, recurrent laryngeal nerves Muscles
Contents of the anterior mediastinum
Internal mammary vessels
Internal mammary and prevascular lymph nodes
Thymus
Contents of middle mediastinum
Heart and pericardium
Ascending and transverse aorta
Main and proximal right and left pulmonary arteries
Confluence of pulmonary veins
Superior and inferior vena cava
Trachea and main bronchi
Lymph nodes and fat within mediastinal spaces
Contents of posterior mediastinum
Descending aorta Esophagus Azygos and hemiazygos veins Thoracic duct Sympathetic ganglia and intercostal nerves Lymph nodes
Triangular or bilobed structure that is maximal in size at puberty and then undergoes gradual fatty involution
Thymus
Thymus is predominantly fatty with little or no intermixed glandular (soft tissue) component at what age
35 years
Anatomic route for routine transcervical mediastinoscopy
Pretracheal space
This space containes fat, lymph nodes, ligamentum arteriosum and left recurrent laryngeal nerve
Aortopulmonary window
Azygos vein is seen on what side
Right
Hemiazygos vein is seen on what side
Left
Represents the junction of the lung with the mediastinum and is composed of upper lobe pulmonary veins and branches of the pulmonary artery and corresponding bronchi
Hilum
The shape of the right hilum on frontal radiographs has been likened to a sideways V, with the opening pointing rightward. The upper portion of V is composed primarily of
Truncus anterior and posterior division of right superior pulmonary vein
Forms the lower half of V of the right hilum
Right interlobar artery
Upper portion of the right hilum is composed of the
Right superior pulmonary vein, truncus anterior division of RPA and right upper lobe bronchus
It courses vertically, anterolateral to the truncus anterior
RUL pulmonary vein
The lower portion of the right hilum is composed of _______ laterally, and _______ medially
Right descending (interlobar) pulmonary artery laterally, Bronchus intermedius and proximal RLL bronchus medially
Upper left hilar shadow is composed centrally of the
Distal left main pulmonary artery
Forms the lower portion of the left hilar shadow as it descends behind the left heart
Descending aorta
The left superior pulmonary vein courses _______ to the left pulmonary artery
Anteriorly
On fronral radiographs, ______ comprise the predominant portion of the hilar opacity
Right and left pulmonary arteries
90% of normal individuals have higher right/left hilar shadow
Left
The avascular aspect of the composite hilar shadow, inferior to the shadow of the right pulmonary artery and veins and anterior to the descending left pulmonary artery and left superior vein is called
Inferior hilar window
This region is roughly triangular in shape, with its apex at the junction of the LUL and LLL bronchi and its base directed anteriorly and inferiorly
Inferior hilar window
A serosal membrane that envelops the lung and lines the costal surface, diaphragm and mediastinum
Pleura
Blood supply to the parietal pleura
Systemic circulation
Blood supply to visceral pleura
Pulmonary circulation
Composed of striated musclr and a large central tendon separating the thoracic and abdominal cavities
Diaphragm
The diaphragmatic muscle arises anteriorly from the
Posterior aspect of xiphoid process
Diaphragmatic muscle arises anterolaterally, laterally and posterolaterally from the
6th to the 12th costal cartilages and ribs
Originate from the upper lumbar vertebrae and course to the posteroor aspect of the central tendon
Diaphragmatic crura
Diaphragm has how many potential openings and how many gaps
3 normal openings and 2 potential gaps
Lies in the midline, immediately behind the diaphragmatic crura and anterior to the 12th thoracic vertebral body
Aortic hiatus
Aorta, thoracic duct and azygos and hemiazygos veins traverse this opening
Aortic hiatus
Usually lies slightly to the left midline, cephalad to the aortic hiatus and transmits the esoohagus and vagus nerves
Esophageal hiatus
The IVC pierces the central tendon of the diaphragm at the level of
8th thoracic intervertebral disc space
Triangular gaps in the muscles of anteromedial diaphragm
Foramina of Morgagni
This cleft is normally occupies by fat and internal mammary vessels; it is a site of potential intrathoracic herniation of abdominal contents
Foramina of Morgagni
defects in the closure of posterolateral diaphragm at the junction of the pleuroperitoneal membrane with the transverse septum
Foramina of Bochdalek
Curvilinear opacities that arise from the upper 2 or 3 lumbar vertebrae
Crura
The central interstitial compartment extending from the mediastinum peripherally and enveloping the bronchovascular bundles is termed
Bronchovascular interstitium
The axial interstitium is contiguous with the interstitium surrounding the small centrilobular arteriole and bronchiole within the secondary pulmonary lobule where it is called the
Centrilobular interstitium
Most peripheral component of the interstitium in which lies between the visceral pleura and lung surface
Subpleural or peripheral interstitium
Invaginations of the subpleural interstitium into the lung parenchyma form the borders of the secondary pulmonary lobules and represent the
Interlobular septa
Extending between the centrilobular interstitium within the lobular core and interlobular septal/subpleural interstitium in the lobular periphery is a fine network of connective tissye fibers that support the alveolar spaces called the
Intralobular, parenchymal or alveolar interstitium
Subsegment of lung supplied by 3-5 terminal bronchioles and separated from adjacent secondary lobules by intervening connective tissue
Interlobular septa
Unit of lung subtended from a single terminal bronchiole is called
Pulmonary acinus
Located at the center of the secondary lobule
Centrilobular artery and preterminal bronchiole
Run at the margins of lobules within the interlobular septa with lymphatics and connective tissue found within the contiguous subpleural interstitium
Pulmonary veins and lymphatics
Interlobular septa are normally ____ mm thick and can be seen in the lung periphery, particularly along the superior and inferior pleural surfaces
1 mm
Normal airways are visible only to within ___cm of the pleura
3cm
When visible, indicates the locations of interlobular septa
Pulmonary veins
Not normally visible on thin section ct
Peribronchovascular, centrilobular, and intralobular interstitial compartments