Thorax 1 & 2 Flashcards
What is the orientation of the heart?
Placed in the thoracic cavity, the apex of the pyramid projects forwards, and inferiorly to the left.
Base: Opposite to the apex, facing the posterior direction
What are the 5 surfaces of the heart?
Diaphgrammatic (Inferior) Anterior (sternocostal) Right pulmonary surfave Left pulmonary surface Base
Which direction does the base of the heart face?
Directed posteriorly, small portion of the right atrium and proximal parts of the superior and inferior vena cavae
Great veins enter the base of heart -> Pulmonary veins enter right and left side of the left atrium
Where do the inferior and superior venae cava drain?
Drain into the right atrium
Where is the base of the heart attached to?
Pericardial wall, opposite the borders of the vertebrae (t5-t8)
Where does the oesphagus lie in relation to the heart?
Posterior
What forms the inferolateral part of the heart?
Apex, left ventricle
Where can the apex of the heart be auscultated?
The left fifth intercostal space
Which cardiac chambers form the anterior surface of the heart?
Right atrium
Right ventricle
Left ventricle
Which chambers form the diaphragmatic surface?
Left ventricle, and small right ventricle
What separates the two ventricles on the posterior surface?
Posterior inter ventricular groove
How is the poster inter ventricular groove separated from the base of the heart?
Coronary sinus
What is the left pulmonary surface?
Faces left lung, broad convex structure consisting of the left ventricle, and a portion of the left atrium.
What is the right pulmonary surface?
Faces the right lung, broad convex structure consisting of the right atrium
What are external heart sulk?
Internal partitions divide the heart into four chambers, produces EXTERNAL grooves = sulk
What is the coronary sulcus?
Circles the heart, separates the atria from the ventricles
Which vessels reside within the coronary sulcus?
Right coronary artery
Small cardiac vein
Coronary sinus
Circumflex branch o fate left coronary artery (LCA)
What do the posterior and anterior inter ventricular sulcus separate?
Separates two ventricles
Which artery resides within the posterior/anterior inter ventricular groove?
Posterior/anterior inter ventricular artery
Where does the middle cardiac vein reside?
Posterior inter-ventricular sulcus
What are the four cardiac chambers?
Right and left ventricle
Right and left atrium
How is the pressure generated for the systemic circulation achieved?
Left ventricle is thicker with greater presence cardiac muscle
Which septum separates the two ventricles?
Interventricular septum
Which septum separates the atria?
Interatrial septum
Which vein saran into the right atrium?
Superior and inferior venae cava
Which sinus is the site of blood drainage from the wall of the heart?
Coronary sinus
Which orifice does the blood from the right atrium pass into the right ventricle ?
Right atrioventricular orifice
When is the atrioventricular closed?
Closed during ventricular contraction by the tricuspid valve
Which valve closes the right atrioventricular orifice?
Tricuspid valve
What is the shallow vertical groove of the right atrium?
Sulcus terminalis cordis
What is the sulcus terminalis cordis?
Extends superior vena cava to inferior vena cava
Which division indicates the the sulcus terminalis cordis?
Crista terminalis
What is the crista terminalis?
Smooth muscular ridge at the roof of atrium, at the opening of superior vena cava, extends inferiorly along the lateral walls to anterior of IVC
What is posterior to the crista terminalis?
Sinus of the vena cava
What is the term for the right atrium proper?
Right auricle
Which muscles cover the atrial walls?
Muscle pectinate (pectinate muscles), fan from crista overlaps the ascending aorta
Where does blood from the cardiac veins drain into?
Opening of the coronary sinus
What is the intertribal septum?
Separates the right atrium from the left
What is the fossa ovalis?
Prominent margin -> Lumbus fossa ovalis
What is the formaina of the venae cordis minimae?
Opening of the cardiac veins, drains myocardium into right atrium
Which cardiac chamber is the most anterior surface of the heart?
Right ventricle, portion of the diaphragmatic surface, anterior and left of the right atrioventricular orifice
What is the outflow of the right ventricle?
Pulmonary trunk
What is attached to the right ventricular walls?
Trabecular carnea
Which muscles are located within right ventricular walls which helps close the tricuspid valve?
Papillary muscles
What is the point of attachment for the cusps of the tricuspid valves?
Chordae tendinae
What is the triscuspid valve?
The right atrioventricular orifice, is closed during ventricular contraction by the tricuspid valve. Base of the cusp secured to the fibrous ring that assist to maintain the shape of the opening.
Cusps are continuous with each other, near the base, termed commissures.
What cusps form the tricuspid valves?
Anterior, septal and posterior
What are the tricuspid cusps attached to?
To chord tendinea from tips of papillary muscles
How does the triscupid valve close during ventricular systole?
During, diastole the tricuspid valve is open, directing the blood flow into the right ventricle; three cusps project into the right ventricle. Contraction of the papillary muscles attached to the cusps by the chordae tendinea prevents the cusps from being exerted into the right atrium (Keeps the valve closed).
How many papillary muscles form one chord tendinea?
2
What happens to the triscupid valve upon myocardial infarction?
Necrosis, resulting in prolapse
Which valve controls the outflow of the right ventricle into the pulmonary trunk?
Pulmonary valve
How many semi-lunar cusps form the pulmonary valve?
3
What is the nodule of a semi-lunar cusp?
Superior edge of the lumen has a thickens portion
What are the three semi-lunar cusps of the pulmonary valves?
left semilunar
Right semi lunar
Anterior semi lunar
How do the pulmonary cusps close after ventricular contraction?
Recoil of blood fills the pulmonary sinuses forces the cusps to close
What vessels drain into the left atrium?
Four pulmonary veins
What is the intertribal septum?
Forms part of the anterior wall of left atrium, the foramen ovale prevents blood passing from the left atrium into the right atrium
How does blood enter into the left ventricle?
Through the left atrioventricular orifices, flows forward direction towards the cardiac apex
What forms the outflow of the left ventricle?
The aortic vestibule
What are the two types of papillary muscles of the left ventricle?
Anterior and posterior papillary muscles.
What forms the anterior wall separating the ventricles?
Interventricular septum
What two parts fo the inter-ventricular septum?
Muscular and membranous part
What is the muscular part of the inter-ventricular septum?
Thick, forms major part of the septum
Which valve closes the left atrioventricular orifice?
Mitral valve
Which cusps form the mitral valve?
Bicuspid valve, therefore anterior and posterior cusps
Which valve closes the aortic vestibule, the outflow tract of the left ventricle?
Aortic valve
How many semi lunar cusps form the aortic valve?
3
What are the three semi-lunar cusps of the aortic valve?
Right
Posterior
Left
Which sinus is considered to be non-coronary?
The posterior sinus
Where do the right and left coronary arteries originate from?
Right and left aortic sinus
How is blood forced into the coronary arteries?
As blood recoils, after ventricular contraction, it fills the aortic sinuses, forced into the coronary arteries
How do veins return back to the coronary sinus?
Cardiac veins
Where is the coronary sinus located?
Located in the coronary sulcus on the posterior surface between the left atrium and left ventricle, empties into the right atrium
Where does the atrial branch of the right coronary artery pass?
Passes in groove between right auricle and ascending aorta , provides the Sino-atrial branch -> Supplies the SAN
What is the main branch of the right coronary artery?
Right marginal branch
What is the right marginal branch?
Gives off as the right coronary artery descends to the inferior margin of the heart towards the apex
Where does the posterior inventricular artery arise from?
Right coronary artery
Which artery resides within the right posterior inter-ventricular sulcus ?
Right coronary artery forming the posterior inter-ventricular artery
What does the RCA supply?
Supplies the right atrium, right ventricle, SAN, AVN and the intertribal septum
Where does the left coronary artery arise from?
Left aortic sinus
Which two branches arise from the left coronary artery?
Anterior inter-ventricular artery (LAD)
Left circumflex
What is the LAD?
Left anterior descending artery, continues on the left side of the pulmonary trunk, apex of the heart int he anterior inter ventricular sulcus (diagonal branches)
What is the circumflex branch?
Courses left in the coronary sulcus and not the base/diaphgrammatic surface. Ends before reaching the interventricular sulcus, the left marginal artery arises from it and continues across around obtuse margin of the heart
What does the left coronary artery supply?
Supplies majority of left atrium
left ventricle, inter ventricular septum
Which artery is dominant and forms the posterior inter-ventricular artery in 80% of population?
Right coronary artery
What does right heart dominant mean?
Right dominant coronary artery: Posterior interventricular branch arises Supplies posterior wall of left-ventricle; left circumflex artery small contributions.
What does left heart dominant mean?
Posterior interventricular branch arises from the left circumflex artery Left coronary artery has significant supply to the posterior wall.
Which vein are received by the coronary sinus?
Four main:
Great, middle small and posterior cardiac vein
Where do the great cardiac vein ascend from?
Begins at the apex, and ascends in the interventricluar sulcus (anterior), related to the anterior inter ventricular artery. Left from coronary sulcus into base
Where does the coronary sinus drain into?
Right atrium
Where is the small cardiac vein located?
Located anterior section of coronary sulcus
Where is the heart contained?
middle mediastinum
How is the heart separated from other structures within the mediastinum?
By the pericardium
What is contained within the mediastinum?
Thymus gland Pericardial sac, heart trachea Major arteries and veins
What is the function of the mediastinum?
Functionally behaves as a passageway enabling the oesophagus thoracic duct and nerve fibres to traverse the abdomen
What is the anatomical location of the mediastinum?
Extends from the sternum and costal cartilages to the bodies of the vertebrae;
What are the vertical boundaries of the mediastinum?
From superior thoracic aperture to the diaphragm
What is the anterior mediastinum?
Is anterior to the pericardial sac, and posterior to the sternum
What is the posterior mediastinum?
Posterior mediastinum is the region posterior to the pericardial sac & diaphragm, and anterior to the vertebral bodies
What is the middle mediastinum?
Middle mediastinum includes the pericardial sac
What is the pericardium?
The pericardium is a fibroserous sac encapsulating the heart and the roots of the great vessels. Consists of two components: Fibrous pericardium, and the serous pericardium.
What are the two main layers of the pericardium?
Serous layer and fibrous layer
What is the fibrous pericardium?
Connective tissue external layer that defines the boundaries of the middle mediastinum. Base on diaphragm, apex continuous with the Adventitia of great vessels.
What forms the phrenic nerve?
C3-C5
Which nerve innervates the fibrous pericardium?
Phrenic nerve
Which vessels supply the fibrous pericardium?
Pericardiophrenic nerve
What are the two layers that form the serous pericardium?
Parietal and visceral layer
What is the parietal layer of the serous pericardium?
Lines the inner surface of the fibrous pericardium
Which layer adheres to the heart forming the outer covering?
Visceral serous pericardium
What is found within the pericardial cavity?
pericardium fluid
What is the function of the pericardial cavity?
Facilitates the relatively uninhibited movement of the heart
What is the first brach of the aortic arch?
Brachiocephalic trunk
What is the point of origin for the brachiocephalic trunk?
Posterior to the manubrium of the sternum
What does the brachiocephalic trunk divide into?
Right common carotid
Right subclavian artery
What is the second branch of the aortic arch?
Left common carotid artery
Describe the location of the left common carotid artery?
Left common carotid artery; arises immediately to the left, and posterior to the brachiocephalic trunk, ascends through the superior mediastinum.
What is the third branch of the aortic arch?
Left subclavian artery,
Describe the location of the left subclavian artery?
Left Subclavian artery; arises immediately left, and posterior to the left common carotid artery, ascends through the superior mediastinum.
Which two veins unite to form the brachiocephalic veins?
Union of the internal jugular vein and the subclavian vein
How does the left brachiocephalic vein meet up with the right?
Left contra laterally traverses to the right, uniting into the superior vena cava with the right
What is the anterior sternocostal surface associated with?
Right ventricle
What is the inferior surface associated with?
Left ventricle
What is the posterior surface associated with?
Left atrium
What does the apex associated with?
Left ventricle
How thoracic vertebrae are there?
12
What forms the lateral thoracic wall?
Ribs (12 on each side)
What are three intercostal muscles?
External intercostal
Internal intercostal
Innermost intercostal
What forms the anterior intercostal?
Sternum
Describe the angle of the manubrium with the body of the sternum?
Posteriorly angled, forming the sternal angle (Angle of Louis)
What are the three structures that form the manubrium?
Body
Sternum
Xiphoid process
What are the true anterior ribs?
Ribs 1 to 7
Why are ribs 1-7 true ribs?
Have direct anterior articulations with the sternum
What are ribs 7 to 10?
False ribs
Why are ribs 7 to 10 false?
Articulates with the inferior margins of the costal cartilage superiorly suspended
Which ribs are floating ribs?
Ribs 11 to 12
What are the borders o the superior thoracic aperture?
Bordered by vertebrae t1; first rib manubrium of sternum
What is the inferior thoracic aperture?
Left Subclavian artery; arises immediately left, and posterior to the left common carotid artery, ascends through the superior mediastinum.
What forms the thoracic inlet?
1st thoracic vertebrae (T1), 1st ribs, and manubrium of sternum.
What is contained within the thoracic inlet?
Conduit for great vessels (Subclavian, and internal jugular vein) heading for neck, and upper limb, oesophagus, trachea and lymphatics
What projects into the root of the neck?
Apex of the right lung
What is the superior articular process?
Superior articular processes: Flat, articular processes face posteriorly
What is the inferior articular process?
project from the laminae, articular facets face anteriorly.
What are the main facets of the vertebrae?
Partial facets
Superior costal
inferior costal
Oval facet
What does the superior costal facet articulate with?
With part of the head of own rib
What does the inferior costal facet articulate with?
Articulates with part of the head of the rib below
What does the first costal rib articulate with?
Manubrium
What does the second costal rib articulate with?
Articulates with manubriosternal joint
What do the 3-7 costal cartilages articulate with?
Body of the sternum
What do the false ribs articulate with?
Anterior superior costal cartilages, articulating with they inferior margin (false ribs)
What do the free floating ribs lack?
An anterior attachment
How do the ribs articulate with on a posterior surface?
Via the head of the rib of the thoracic vertebrae (facet o the superior articular process)
Tubercle is articulates with the facet of the transverse process
What does the costal cartilage attach too?
Attaches the rib to the sternum
What is the inferior margin of the rib?
Costal groove
What is deep to the intercostal spaces separating the structures from the underlying pleura?
Endothoracic fascia (Variable layers of fat)
What is superficial to the intercostal spaces?
Deep fascia, superficial fascia and skin
What is the order of the neuromuscular bundles in the costal groove superior to inferior?
Veins
Artery
Nerve
Which intercostal muscles are most superficial?
External intercostal muscles
What is the superior attachment of the external intercostal muscles?
Inferior margin of the rib above
How many pairs of intercostal muscles are there ?
11
Which direction to the external intercostal muscle fibres move?
Extend from inferior margins of the ribs above to the superior margins to the ribs below, obliquely anteroinferorly.
Which intercostal muscles reside intermediate to the internal and inner most?
Internal intercostal muscles
What direction to the internal intercostal muscles point?
Pass most inferior lateral edge to spoiler margins of the ribs below, pass obliquely, posterior inferiorly
Which is the deepest intercostal muscles?
Innermost intercostal muscles
What are the orientation of the innermost intercostal muscles?
Same as internal intercostal muscles
Where do the thoracic arteries arise from?
Subclavian arteries
What are the two main arterial supplies to the thoracic wall?
Anterior and posterior intercostal arteries
Where do the upper two posterior intercostal arteries arise from?
Supremer intercostal artery
How many pairs of posterior intercostal arteries are there?
9 Pairs
Where do the 9 pairs of posterior intercostal arteries arise from?
Arise from the posterior surface of the thoracic aorta (left side of the vertebral column), posterior intercostal vessels passing right side cross midline anterior to the border
Where do the anterior intercostal arteries arise from?
As lateral branches from the internal thoracic arteries, each internal thoracic artery arises as a major branch of the subclavian artery
What is the central venous drainage of the thoracic wall?
Azygous system odf veins
Where do the azygous system of veins eventually drain?
Into the brachiocephalic veins
Where do the upper posterior intercostal veins drain into?
Left superior intercostal veins empties into left brachiocephalic
Where does the right superior intercostal vein empty into?
Azygous vein
Which nerves innervate the majority of the thoracic cavity?
Intercostal nerves
Which spinal nerves form the majority of the intercostal neves?
T1-T11
What is the subcostal nerve?
T12
Where does the subcostal nerve lie in relation to the rib XII?
Inferior to rib XII
Which intercostal nerve branch passes laterally around the thoracic wall in an intercostal space?
Lateral cutaneous
What two branches does the lateral cutaneous branch into?
Anterior and posterior branch
Where does the anterior cutaneous branch emerge from?
Emerges parasternal between adjacent costal cartilages
What two branches does the anterior cutaneous branch divide into?
Lateral nad medial branches
Which artery supplies the 7th to 9th intercostal spaces?
Musculophrenic artery
Which artery supplies the 10 and 11th intercostal spaces?
Posterior intercostal arteries
What is the diaphragm?
Flat central tendon with muscle radiating to costal margin and vertebrae
How does the diaphragm increase thoracic volume?
Dome flattens; the increases the vertical diameter of the chest; pulls the costal making up to increase transverse and anteroposterior diameters.
What role do the intercostal muscles play during breathing?
Secondary role to stiffen the chest wall to improve efficiency of breathing movements. Intercostal muscles are situated between adjacent ribs
sternum and ribs help increase the thoracic volume
What happens when the diaphragm contract?
The height of. the dome decreases, subsequently increasing thoracic volume
What is the relation of the aorta and diaphragm?
Aorta passes posteriorly
Vena cava most anterior
Where does the oesophagus penetrate the diaphragm?
T10
Where does the aortic hiatus penetrate the diaphragm?
T12
Where does the vena cava penetrate the diaphragm?
T8
Which nerve innervates the diaphragm?
Phrenic nerve
Where does the diaphragm occupy?
Occupies the inferior thoracic aperture, separates the thoracic cavity from the abdominal cavity
Which part of the sternum does the diaphragm end with?
Xiphoid process
Which ribs does the diaphragm end at?
Ribs 11 & 12
What is the action of the intercostal muscles?
Elevates the ribs, increasing the thoracic volume. Pull ribcage up and out (Inspiration )
ACTIVE process
What type of process is exerted by the external intercostal muscles?
Active process
Describe the orientation of the external intercostal muscle fibres?
Downwards and medially from the inferior margin of the rib above to the superior margin o nth rub below
What is the muscle replaced with at the rib cartilage junction?
Membrane
Which nerves innervate the external intercostal muscles?
T1-T11 INTERCOSTAL nerves
What bundle separates the internal and inner most intercostal muscles?
Neurovascular bundles residing within the lateral portion o fit intercostal spaces.
Describe the attachments of the inner most intercostal muscle?
Originates from the medial edge of the costal groove, inserting into the superior surface of the rib below
What are the actions of the innermost intercostals?
The interosseous region reduces the thoracic volume by depressing the ribcage, the interchodnral part elevates the ribs
What effect does the internal intercostal muscles have on the ribcage?
Pulls ribcage downward and inwards = forced expiration
What are the borders of the chest drain safe area?
Anterior border of lattismus dorsi
Lateral border of the pectorals major
A lie superior to the horizontal nipple, and apex below the axilla, the drain should be inserted just above the rib
What lines each pleural cavity?
Mesothelium
What is a mesothelium?
A thin layer of flattened cells supported by connective tissue that lines each pleural cavity, and covers the exterior of the lungs
What is parietal pleura?
Associated with walls of a pleural cavity
What are the three parts of the parietal pleura?
Costal part
Diaphragmatic part
Mediastinal part
What is the costal part of parietal pleura?
Related to the ribs and the intercostal space
What is the diaphragmatic part of the parietal pleura?
Covers the diaphragm
What is the mediastinal part of the parietal pleura?
Covers the mediastinum
What is the cervical pleura?
Dome shaped layer of parietal pleura lining the cervical extension of the pleural cavity, innervated by somatic efferent fibres
What covers the superior surface of the cervical pleura?
Suprapleural membrane
What is the supra pleural membrane?
Connective tissus membrane is attached laterally to the medial margin of the first rib
What is visceral pleura?
Reflects from the medial wall onto the surface of the lungs adheres and covers the lung
Where is the visceral pleura continuation with the parietal pleura?
At the hilum of each lung
What is a potential space?
Enclosed within the visceral and parietal pleurae, containing serous fluid
What fluid is contained within the potential space?
serous fluid
What layer covers the surface of the lung?
Visceral pleura
What is a pleural recess?
Lungs do not completely fill the anterior or posterior inferior regions of the pleural cavities, recess - > Two layers of parietal pleura become opposed
Expansion of lungs into spaces occurs during forced inspiration, recess provides potential space in which flies can collect, and from which fluids can be aspirated
What is the costodiaphgramatic recess?
Occurs between the costal pleura and diaphragmatic pleura
Regina between the inferior margin of the lungs, and the inferior margin of the pleural cavities
Deepest after forced expiration and shallowest after forced inspiration
What is pleural effusion?
Occurs when excess fluid accumulates within the pleural space, fluid accumulation within the pleural space the underlying is composed, and may collapse as the volume of fluid increases
What is a pneumothorax?
Air within the pleural cavity
Which cavities surround both the left and right lung?
Pleural cavities
How does air leave and enter through into the lungs?
Primary bronchi (branches of the trachea)
Describe the relative location of the pulmonary artery at the hilum of the left lung?
most superior
What is the role of pulmonary arteries?
Delivers deoxygenated blood to the lungs from right ventricle of the heart
How is oxygenated blood returned back to the heart?
Returns to the left atrium through the pulmonary veins
Which lung is bigger than the other?
Right lung
Why is the right lung is larger than the left?
The middle mediastinum, containing the heart bulges more to the left than the right
Describe the base structure of the lungs ?
Concave base
Why do the lungs have a concave base?
The diaphragm is convex
What structure does the diaphragm separate on the right side?
Right lung from the right lobe of the liver
What abdominal organs are separated from the left lung?
Left lobe of the liver, stomach and spleen
Which rib does the lung apex project above?
Rib 1
What are the three surfaces of the lungs?
Costal surface
Mediastinal surface
Diaphragmatic surface
What is the costal surface of the lung?
Lies immediately adjacent to the ribs and intercostal spaces fo the thoracic wall.
What is the mediastinal surface of the lung?
Against the mediastinum anteriorly, and the vertebral column posterior, contains the hilum of the lung
Which surface of the lung contains the hilum?
Mediastinum
What are the three borders of the lung?
Inferior
Posterior
Anterior
What is the inferior border of the lung?
Inferior border of the lung is sharp and separates the base from the costal surface
What is the anterior and posterior borders of the lung?
Separates the costal surface from the medial surface
Which pleura covers the hilum?
Mediastinal pleura
Which structures enter and leave the hilum?
Principal bronchus Pulmonary artery Pulmonary veins Bronchial arteries Pulmonary plexus of nerves
What are the two fissures of the right lung?
Oblique fissure and horizontal fissure
What is the main fissure of the left lung?
Oblique fissure
What are the three lobes of the right lobe?
Upper lobe
Middle lobe
Lower lobe
Which ligament stabilises the position of the lower lobe?
Pulmonary ligament
Which structure is most superior at the hilum in the left lung?
Pulmonary artery
Which structures are most inferior at the hilum of the lungs
Pulmonary veins
Where does the main bronchus reside in relation to the lung?
Posterior in position
What is the main impression on the left lung?
Cardiac impression of the aortic arch and thoracic aorta
What is the main impression on the right lung?
Azygous vein impression
Where does the trachea extend from the vertebral level?
C6 TO T4/5
Which type of cartilage holds open the trachea?
C-shaped cartilage rings
What forms at the inferior margin of the trachea?
Carina
What happens at the carina?
Bifurcation into the primary left and right bronchi
At what vertebral level does the trachea bifurcate at?
T4/5
Why are objects are likely to be aspirated into the right lung than the left?
The right primary bronchi has a relatively larger diameter and takes a more vertical course in comparison to the left bronchi
What bronchi are formed within the lungs from the primary bronchi?
Lobar secondary bronchi
What is the name of tertiary bronchi?
Segmental bronchi
Which bronchi supply the bronchopulmonary segments?
Segmental bronchi
What is the average number of bronchopulmonary segments in each lung?
10
What supplies each bronchopulmonary segment?
Pulmonary artery branch and segmental bronchus
What does the oblique fissure separate ?
Separates the lower lobe from the upper lobe and the middle lobe of the right lung
What does the horizontal fissure separate?
Separates the superior lobe from the middle lobe
What forms the superior vena cava?
union of the left and right brachiocephalic veins
Which vein drains blood within the thoracic wall?
Azygous vein
The movements of which two structures is associated with increases the capacity of the thoracic cavity?
Diaphragm
Ribs
How is the pleural cavity expended during breathing?
Expanded by muscles in the wall, the elastic lungs expand with the pleural cavity, this reduces intrathoracic pressure, generating a pressure potential gradient, inhalation of air through the trachea and bronchi into the lungs
What is quiet expiration?
Passive activity not requiring muscles; depends on the elastic recoil in the elastic tissue throughout the lungs and ribcage
What is forced expiration?
Assisted by muscles of the abdominal walls that compresses the abdominal organs against the diaphragm and pull the lower ribs downwards
What is the most anterior structure within the diaphragm?
Inferior vena cava
How is the vertical dimension of the thoracic cavity affected during contraction of the diaphragm?
Increases
What happens do the abdominal viscera due to diaphragm contractions?
Descend due to relaxation of the abdominal wall during inspiration
What is the diagram attached to?
The diaphragm is attached to:
Costal margin (lower border of the rib cage
Xiphoid process
Ends of the free floating ribs (XI & XII)
Lumbar vertebrae posteriorly
The dome of the diaphragm expands superiorly into the ribcage High abdominal organs including the liver are covered by the diaphragm, pleura & lung.
