Thorax Anatomy Flashcards
Borders of the superior thoracic aperture
- Posterior = body of T1
- Lateral = medial border of 1st rib
- Anterior = manubrium
Borders of the inferior thoracic aperture
- Posterior = body of T12
- Posterolateral = rib 12 and distal end of rib 11
- Anterolateral = distal ends of ribs 7-10 and costal cartilage
- Anterior = xiphoid process
Characteristics of a thoracic vertebrae
- Heart-shaped body
- Long spinous process
- Circular foramen
- Broad lamina
- Flat superior articular surfaces
- Club-shaped transverse processes
What are the true ribs and why
- Ribs 1-7
- Articulate with the sterum directly
What are the false ribs and why
- Ribs 8-10
- Articulate anteriorly with the costal cartilage of the ribs above
What are the floating ribs and why
- Ribs 11 and 12
- Free anteriorly
List the 3 articulations of ribs 2-9
- Superior costal facet (with head of its own rib)
- Inferior costal facet (with head of rib below)
- Transverse costal facet (with tubercle of its own rib)
Describe the posterior formation of a typical rib
- Head - expanded with two articular facets
- Neck - separates head from tubercle
- Tubercle
Which rib border contains the costal groove
Inferior border
Describe the scalene tubercle of the 1st rib
- Two grooves present on superior surface
- Anterior caused by subclavian vein
- Posterior by subclavian artery and lowest trunk of brachial plexus
- Functions as attachment of scalenus anterior
What structures are attached to the 1st rib
- First digitation of serratus anterior
- Sibson’s fascia to inner border
Fracture of which ribs risk splenic trauma
9-11
Why does rib notching occur in coarctation of the aorta
- Collateral vessels develop above and below the blockage
- Superior intercostal artery supplies blood to intercostal arteries of aorta to bypass blockage
- Intercostal vessels dilate and erode the lower border of the ribs
Compromise caused by cervical rib
- Post-stenotic dilatation of the subclavian artery
- Subclavian aneurysm
- Subclavian vein thrombosis
- C8/T1 paraesthesia
Which costal cartilages articulate with the manubrium
First and upper parts of sternum
What is the angle of Louis
Articulation between body of sternum and manubrium
Anatomical relations of the manubrium
- Anterior boundary of superior mediastinum
- Lowest part related to arch of aorta
- Left brachicephalic artery and vein, left common carotid, left subclavian
- Laterally to pleura
Which ribs does the body of the sternum articulate with
Contains facets for ribs 2-7 (demifacets for 2 and 7)
What type of cartilage is costal cartilage
Hyaline
Describe the costovertebral joints
- Facets of the rib head with facets of the vertebrae above and below
- Contain two synovial compartments divided by the intra-articular ligament
- It is a synovial plane joint
Describe the costotransverse joints with its ligaments
- It is a synovial plane joint
- Between rib tubercle and transverse process of corresponding vertebrae
- Costotranverse ligament
- Lateral costotransverse ligament
- Superior costotransverse ligament
Describe the sternocostal joints
- Between rib and sternum
- 1st is a primary cartilaginous jount (symphysis)
- 2nd to 7th are plane synovial joints
- Joint between 2nd rib and sternum has two compartments separated by an intra-articular ligament
What type of joint is the manubriosternal joint
Secondary cartilaginous joint (symphysis)
Outline the 3 muscles contained within the intercostal spaces
- External intercostal - fibres pass downwards. Most active on INSPIRATION. Moves ribs superiorly.
- Internal intercostal - fibres pass backwards. Most active on EXPIRATION. Moves ribs inferiorly.
- Innermost intercostals - may cover more than one intercostal space
Innervation of the 3 layers of intercostal muscles
All are innervated by the intercostal nerves of T1-11
Describe the subcostal muscles
- Same plane as innermost intercostals
- Span multiple ribs
- Extend from innermost surface of one rib to internal surface of next
Describe the transversus thoracis muscles
- Found on deep surface of anterior thoracic wall
- Same plane as innermost intercostals
- Originate from xiphoid process, inferior part of body of sternum, adjacent costal cartilages of lower true ribs
- Pass superiorly and laterally to insert into costal cartilages of ribs 3-6
List the order of the neurovascular bundle from superior to inferior
- V = intercostal vein
- A = intercostal artery
- N = intercostal nerve
Origin of the posterior intercostal arteries
- Upper two = supreme intercostal, branch of costocervical branch of subclavian
- Lower nine = posterior surface of thoracic aorta
Origin of the anterior intercostal arteries
Directly or indirectly as lateral branches of the internal thoracic arteries
Describe the course of the internal thoracic artery
- Branch of subclavian
- Passes anteriorly over dome of pleura and through superior thoracic aperture
- Descends down deep aspect of thoracic wall 1cm lateral to the sternum
- Divides into superior epigastric and musculophrenic artery at level of 6th intercostal space
What artery supplies the intercostal spaces below the 6th rib
Musculophrenic artery
Describe the course and distribution of the anterior intercostal arteries
- Supply the upper 6 ribs
- Have two branches:
1. Passes below margin of upper rib in subcostal groove
2. Passes above margin of lower rib to meet collateral branch of posterior intercostal
Outline the venous drainage of the intercostal spaces
- Intercostal veins
- Azygous vein posteriorly or internal thoracic veins anteriorly
- Internal throacics drain into brachiocephalic and azygous drain into SVC
What supplies sensory innervation to the skin overlying the upper thoracic wall
Cutaneous branches of the supraclavicular plexus which descends from the cervical plexus
Origin of the subcostal nerve
Anterior ramus of T12
List the 3 divisions of the muscular diaphragm
- Sternal part
- Costal part
- Lumbar part
Attachment of the sternal part of the diaphragm
Xiphoid process
Attachment of the costal part of the diaphragm
Internal surfaces of the inferior 6 costal cartilages and their adjoining ribs and forms the domes of the diaphragm
Constituents of the lumbar part of the muscular diaphragm
- Medial arcuate ligament
- Lateral arcuate ligament
- Three superior lumbar vertebrae
Describe the medial arcuate ligament
- Condensation of fascia over psoas major
- Spans between lumbar vertebral bodies and tip of L1 transverse process
- Medial borders join over aorta to form median arcuate ligament
Origin of the right crus
Front of the bodies of L1-3 and their discs
Origin of the left crus
L1-2
Contents of the aortic opening
- Abdominal aorta
- Thoracic duct
- Azygous vein
Level of aortic opening
T12
Site of aortic opening
Behind medial arcuate ligament
Contents of oesophageal opening
- Oesophagus
- Vagus nerve
- Branches of the left gastric artery and veins
Level of the oesophageal opening
T10
Contents of the caval opening
- IVC
2. Right phrenic nerve
Level of the caval opening
T8
Describe the sternocostal triangle of the diaphragm
- Situated between sternal and costal attachments of the diaphragm
- Transmits lymphatic vessels and superior epigastric vessels
Arterial supply of the superior surface of the diaphragm
- Superior phrenic arteries from thoracic aorta
- Musculophrenic arteries
- Pericardiophrenics
Arterial supply of the inferior surface of the diaphragm
Inferior phrenic arteries from the abdominal aorta
Venous drainage of the superior surface of diaphragm
Musculophrenic and pericardiphrenic veins drain into the internal thoracic veins
Venous drainage of the inferior surface of the diaphragm
- Right inferior phrenic vein drains into IVC
- Left inferior phrenic vein drains into IVC and suprarenal vein
Lymphatic drainage of superior surface of diaphragm
In order of flow:
- Diaphragmatic nodes
- Phrenic nodes
- Parasternal nodes and posterior mediastinal nodes
Lymphatic drainage of inferior surface of diaphragm
Superior lumbar lymph nodes
Motor innervation of the diaphragm
Phrenic (C3-5)
Sensory innervation of the diaphragm
- Centrally = phrenic
- Peripherally = intercostal nerves (T5-11) and sub-costal (T12)
Describe the bucket-handle action of the ribs
Raising of ribs 4-7 increases the transverse diameter of the thorax
What is the pulmonary ligament
Fold of loose pleura below the root of the lung which permits distension of the pulmonary vein
List the 3 parts of the parietal pleura
- Costal
- Mediastinal
- Diaphragmatic
What separates the costal parietal pleura from the thoracic wall
Endothoracic fascia
Where does the parietal pleura reflect to become visceral pleura
Root of the lung
What connects the diaphragmatic parietal pleura to the muscular part of the diaphragm
Phrenicopleural fascia
Describe the pleural cupula
Dome of cervical pleura at the apex of the lung - reinforced by Sibson’s fascia (suprapleural membrane) that attaches to the internal borders of the 1st rib and transverse process of C7
Features of the costal surface of the lung
- Large, smooth and convex
- Related to the costal pleura
- Posterior part is related to the bodies of the thoracic vertebrae
Features of the mediastinal surface of the lung
- Concave
- Inclusive of the hilum
Features of the diaphragmatic surface of the lung
- Base of the lung
- Concave
Describe the anterior border of the lung
- Meeting of the costal and mediastinal surfaces anteriorly
- Indented by the cardiac notch on the left
Describe the inferior border of the lung
Circumscribes the diaphragmatic surface and separates it from the mediastinal and costal surfaces
Describe the posterior border of the lung
Meeting of the costal and mediastinal surfaces posteriorly
When during gestation is the diaphragm formed
Between 5th and 7th weeks
What is the diaphragm formed from embryologically
Progressive fusion of the septum transversum, pleuroperitoneal folds, and lateral muscular ingrowth
What is the origin of the central tendon of the diaphragm
Septum transversum
Which lung is larger
Right
Outline the structure of the right lung
- Three lobes = superior, middle, inferior
- Two fissures = right oblique, horizontal
- Mediastinal surface contains groove for oesophagus and cardiac impression
Outline the structure of the left lung
- Two lobes = superior and inferior
- One fissure = left oblique
- Infero-anterior tongue-like projection = lingula
- Anterior border contains cardiac notch
- Contains continuous groove for arch and descending aorta
Describe the structure of the lung root
- Pulmonary artery - superior left
- Superior pulmonary vein - anterior-most
- Inferior pulmonary vein - inferior-most
- Main bronchus - against and in the middle of the posterior boundary
Level of carina
Lower border of T4 (transverse thoracic plane)
Structure of the trachea
- Fibroelastic tissue and U-shaped cartilaginous rings that are open posteriorly
- Trachealis (smooth muscle) connects the edges
- Lined by columnar epithelium containing numerous goblet cells
Length of right main bronchus
2.5cm
Anatomical relations of the right main bronchus
- Passes down/lateral and behind the ascending aorta and SVC
- Azygous vein arches over it to enter SVC
- Pulmonary artery lies first below and then anterior
Course and divisions of right main bronchus
- Passes down/lateral and behind the ascending aorta and SVC
- Gives off the upper lobe bronchus before entering the lung
- Divides into middle and lower lobe bronchi within the lung
Length of left main bronchus
5cm
Course of left main bronchus
- Passes down and lateral below the arch of aorta
- Passes in front of the oesophagus and descending aorta
- Pulmonary artery lies first anterior to and then above the bronchus
List the order of bronchus division
- Main bronchus
- Lobar bronchi
- Segmental bronchi (to bronchopulmonary segments)
- Conducting bronchioles
- Terminal bronchioles
- Respiratory bronchioles
- Alveolar ducts
- Alveolar sacs
- Alveoli
How many bronchopulmonary segments are there
10
What must a bronchopulmonary segment have
Its own:
- Segmental bronchus
- Segmental artery
- Segmental vein
Outline the course of de-oxygenated blood from the heart to the alveoli
- Right ventricle
- Pulmonary trunk
- Right and left pulmonary arteries
- Lobar arteries
- Tertiary segmental arteries
What is the orientation of the pulmonary arteries to their corresponding bronchus
Artery is usually anterior
Course of the right pulmonary artery
- Passes in front of oesophagus
- Behind ascending aorta and SVC
- Divides into three branches
Course of the left pulmonary artery
- Connected at its origin to the arch of aorta by the ligamentum arteriosum
- Runs in front of left main bronchus and descending aorta
Which pulmonary vein does blood from the middle lobe drain into
Inferior pulmonary vein
Describe the route of oxygenated blood from the lungs to the heart
- Superior and inferior pulmonary veins
2. Left atrium
Outline the bronchial blood supply
Bronchial arteries are branches of the thoracic aorta (two left, one right)
Outline the venous drainage of the bronchial tree
- Bronchial veins drain blood proximally near the hilum (remainder drained by pulmonary veins)
- Right bronchial vein drains into azygous vein
- Left bronchial vein drains into the accessory hemi-azygour veins or the left superior intercostal vein
Innervation of the visceral pleura
Autonomic supply from branches of the vagus sensitive to stretch
Innervation of the parietal pleura
Somatic innervation from the intercostal nerves
Innervation of the diaphragmatic pleura
Phrenic nerve
Which parts of the pleura are sensitive to pain
- Parietal
- Diaphragmatic
Surface anatomy of the lower border of the lung
- 6th rib in MCL
- 8th rib in mid-axillary
- 10th rib at lateral border of erector spinae
Surface anatomy of inferior edge of pleura
Two ribs lower than the corresponding lung level
Anatomical relations of the hilum of the RIGHT lung
- Above = azygous vein and above this is the groove for SVC
- Behind = vertical groove for oesophagus
- Anterior = SVC and right atrium
Anatomical relations of the hilum of the LEFT lung
- Above = furrow of aortic arch and above this groove for left subclavian
- Behind = groove for descending aorta
Describe the course of the LEFT phrenic nerve
- Passes with IJV across anterior scalene and deep to prevertebral fascia
- Crosses anterior to 1st part of subclavian
- Runs posterior to subclavian vein and posterior to internal thoracic artery
- Passes lateral to left subclavian, aortic arch and left ventricle
- Passes anterior to root of lung
- Pierces diaphragm alone
Describe the course of the RIGHT phrenic nerve
- Passes with IJV across anterior scalene deep to preverterbal fascia
- Crosses anterior to 2nd part of subclavian artery
- Runs posterior to subclavian vein and posterior to internal thoracic artery
- Runs anterior to right vagus and lateral to SVC
- Travels to right of pericardium
- Passes over right atrium to exit diaphragm at T8 with the vena cava
What plane divides the mediastinum into superior and posterior compartments
Transverse thoracic plane (T4/T5)
What are the further divisions of the inferior mediastinum
- Middle mediastinum
- Anterior mediastinum
- Posterior mediastinum
What structure subdivides the inferior mediastinum
Pericardium
List the contents of the superior mediastinum
- SVC
- Brachiocephalic veins
- Arch of aorta
- Thoracic duct
- Trachea
- Oesophagus
- Thymus
- Vagus nerve
- Left recurrent laryngeal nerve
- Phrenic nerve
List the contents of the anterior mediastinum
- Thymic remnants
- Lymph nodes
- Fat
List the contents of the middle mediastinum
- Pericardium
- Heart
- Aortic root
- Arch of azygous vein
- Main bronchi
List the contents of the posterior mediastinum
- Oesophagus
- Thoracic aorta
- Azygous vein
- Thoracic duct
- Vagus nerve
- Sympathetic nerve trunks
- Splanchnic nerves
What are the two parts that make up the pericardium
- Fibrous pericardium
2. Serous pericardium
Layers of the serous pericardium
- Parietal
2. Visceral (epicardium)
Where are the parietal and visceral layers of the serous pericardium continuous with each other
- Where the aorta and pulmonary trunks leave the heart
- Where the SVC and IVC enter the heart
Describe the attachments of the fibrous pericardium
- Pericardiophrenic ligament = continuous inferiorly with central tendon of diaphragm
- Continuous superiorly with the tunica adventitia of the great vessels
- Sternopericardial ligament = anterior attachment to posterior surface of the sternum
Where does the pericardial cavity lie
Between the two layers of serous pericardium (visceral and parietal)
Arterial supply of the pericardium
Pericardiacophrenic artery (branch of the internal thoracic artery)
Venous drainage of the pericardium
- Pericardiacophrenic veins (tributaries of brachiocephalic vein)
- Variable tributaries of the azygous vein
Via what nerve is pain transmitted from the pericardium
Phrenic nerve (C3-5) - referred pain felt at the top of the shoulders
List the 5 surfaces of the heart
- Anterior
- Posterior (base)
- Inferior (diaphragmatic)
- Right pulmonary
- Left pulmonary
Contents of the anterior surface of the heart
- Right atrium
- Right ventricle
- Narrow strip of left ventricle
Contents of the base of the heart
- Left ventricle
- Left atrium
- Four pulmonary veins entering left atrium
Contents of the inferior (diaphragmatic) surface of the heart
- Right atrium
- IVC entering right atrium
- Lower part of ventricles
On the surface of the heart what demarcates the atria from the ventricles
Coronary sulcus (AV groove)
On the surface of the heart what demarcates the right and left ventricles
Anterior and posterior interventricular sulci
What forms the right heart border
Right atrium with IVC and SVC
What forms the inferior border of the heart
Right ventricle and apex of left ventricle
What forms the left border of the heart
Left ventricle and auricle of the left atrium
Chest wall anatomical relations of the heart
- Posterior sternum
- Medial ends of the 3rd-5th ribs on the left and their costal cartilages
What causes the first heart sound
Closure of the atrioventricular (mitral and tricuspid) valves
What causes the second heart sound
Closure of the aortic and pulmonary valves
What are the layers of the heart wall
- Endocardium
- Myocardium
- Epicardium
What anchors the cardiac muscle
Cardiac fibrous skeleton
Internal features of right atrium
- Sinus venarum = smooth posterior aspect where vena cava and coronary sinus open
- Rough anterior wall of pectinate muscles
- Fossa ovalis
- Crista terminalis (opening of right atrial appendage)
What separates the smooth and rough parts of the right atrium
- Externally = sulcus terminalis
- Internally = crista terminalis
Internal features of the right ventricle
- Infundibulum = outflow tract to pulmonary artery
- Trabeculae carnae = muscular projections
- Moderator band prevents over-expansion of the ventricle
- Anterior, posterior and septal papillary muscles
Describe the tricuspid valve
- 3 cusps (septal, anterior, posterior)
- Smooth atrial surface
- Ventricular surface attached to chordae tendinae
- Chordae tendinae attach to papillary muscles of the ventricular wall
Where does the auricle of the left atrium lie
Overlaps the commencement of the pulmonary trunk
Interior features of the left atrium
- Large smooth walled part
- Muscular auricle of pectinate muscles
- Thicker and smaller than right atrium
Interior features of the left ventricle
- Twice as thick as the right ventricle
- Much thicker and more numerous trabeculae carnae
- Papillary muscles to the chordae tendinae of the anterior and posterior mitral cusps
How many cusps do both the aortic and pulmonary valves have
3
Where are the aortic sinuses situated
Anatomical dilatation of the ascending aorta just above the aortic valve
Function of the aortic sinuses
They give rise to the coronary arteries
Where do the great, middle and small cardiac veins drain
Coronary sinus (which opens into right atrium)
Course of the right coronary artery
- Originates from right aortic sinus
- Follows coronary sulcus between atria and ventricles
- Anastomoses with circumflex and anterior IV branches of LVA
Distribution of the right coronary artery
- Right atrium
- SAN, AVN
- Posterior parts of IVS
Course of the right marginal artery
- Originates from RCA
- Passes to inferior margin of heart and apex
- Anastomoses with IV branches
Distribution of the right marginal artery
- Right ventricle
- Apex
Course of the left coronary artery
- Originates from left aortic sinus
- Courses between pulmonary trunk and left atrial appendage
- Runs in AV groove to give off anterior IV and circumflex branches
- Anastomoses with RCA
Distribution of the left coronary artery
- Left atrium
- Left ventricle
- IVS
- AV bundles
Course of the posterior interventricular artery
- Originates from RCA
- Runs in posterior IV groove to apex
- Anastomoses with anterior IV branch of LCA
Distribution of posterior interventricular artery
- Right ventricle
- Left ventricle
- Posterior 1/3rd of IVS
Course of the anterior interventricular artery (LAD)
- Originates from LCA
- Runs in anterior IV groove to apex
- Anastomoses with posterior IV branch of RCA
Distribution of the anterior interventricular artery (LAD)
- Right ventricle
- Left ventricle
- Anterior 2/3rd of IVS
Course of the circumflex artery
- Originates from LCA
- Passes to the left in AV sulcus and runs to posterior surface
- Anastomoses with RCA
Distribution of the circumflex artery
- Left atrium
- Left ventricle
Artery blocked in inferior MI
Right coronary artery
Artery blocked in lateral MI
Circumflex
Artery blocked in septal MI
LAD
Artery blocked in anterior MI
Right coronary artery
Location of the SAN
- Anterolaterally
- Just deep to epicardium
- At junction of the SVC and right atrium
Arterial supply of the SAN
SA nodal branch of RCA
Location of the AVN
Posteroinferior region in the interatrial septum near the opening of the coronary sinus
Arterial supply of the AVN
AV nodal artery (branch of the interventricular artery, branch of RCA)
Function of AVN
Distributes the myogenic signal from SAN through the AV bundle (bridge between atrial and ventricular myocardium)
Outline the innervation of the heart
- Supplied by autonomic fibres of the cardiac plexus which lies anterior to bifurcation of trachea
- Sympathetics from cell bodies in the intermediolateral cell columns of T1-5/6 which send post-synaptic cardiopulmonary splanchnic nerves
- Parasympathetic is via vagus nerve
Divisions of the left coronary artery
- LAD
- Circumflex
- Left marginal
Superior mediastinum contents from anterior to posterior
- Thymus
- Great vessels (with veins anterior to arteries)
- Trachea
- Left recurrent laryngeal
- Oesophagus
- Thoracic duct and lymphatic trunks
Describe the thymus
- Primary lymphoid organ
- Flat gland with flask-shaped lobes
- After puberty it undergoes involution and is replaced primarily by fat
Blood supply of the thymus
Anterior intercostal and anterior mediastinal branches of the internal thoracic arteries
Where is the brachiocephalic vein formed and by what
- Posterior to the sternoclavicular joints
- Union of IJV and subclavian veins
Where do the brachiocephalic veins unite to form the SVC
Level of 1st costal cartilage
At what level does the SVC enter the right atrium
Level of 3rd costal cartilage
At what level does the azygous vein join the SVC
Transthoracic plane (T4/5)
Describe the course of the arch of aorta
- Begins posterior to 2nd right sternocostal joint at the level of the sternal angle
- Arches superiorly, posteriorly, and left anterior to right pulmonary artery
- Turns inferior and descends posterior to left lung root
- Becomes descending aorta at 2nd sternocostal joint
Describe the ligamentum arteriosum
- Connects root of left pulmonary artery to inferior surface of aortic arch
- Remnant of fetal ductus arteriosus
What constitutes the azygous venous system
- Azygous vein
- Hemiazygous vein
- Accessory hemiazygous veins
- Left superior intercostal vein
Function of the azygous venous system
Drain the thoracic wall and upper lumbar region via the lumbar veins and posterior intercostal veins
Describe the course of the azygous vein
- Arises from union of right ascending lumbar vein and right subcostal vein at T12
- Enters thorax via aortic hiatus
- Ascends on right side of vertebral bodies, arching over right main
- Enters SVC at T4
What does the accessory azygous vein drain
Superior left hemithorax
At what level does the hemiazygous vein join the azygous vein
Crosses under oesophagus to joint at T9
Describe the course of the brachiocephalic trunk
- First branch of aortic arch
- Arises posterior to manubrium and anterior to trachea
- Posterior to left brachiocephalic vein
- Divides into right subclavian and common carotid at level of SC joint
Outline the course of the vagus nerve
- Exits cranium via jugular foramen
- Descends in carotid sheath posterolateral to common carotid
- Enters mediastinum posterior to SC joint and brachiocephalic vein
- Right vagus enters thorax anterior to subclavian and gives off right RLN that hooks around right subclavian
- Left vagus enters mediastinum between left common carotid and left subclavian (separated from phrenic by left superior intercostal vein). Gives of left RLN which passes inferior to arch of aorta lateral to ligamentum arteriosum
Difference in path of phrenic and vagus nerves at lung root
- Vagus passes POSTERIOR
- Phrenic passes ANTERIOR
Outline the course of the right phrenic nerve
- Enters mediastinum between subclavian artery and brachiocephalic vein
- Pass anterior to roots of the lungs
- Passes alongside right brachiocephalic vein, SVC and pericardium over the right atrium
Outline the course of the left phrenic nerve
- Enters mediastinum between subclavian artery and brachiocephalic vein
- Descends between left subclavian and left common carotid
- Crosses the left surface of the aortic arch
- Runs anterior to lung root
- Descends along the fibrous pericardium superficial to the left atrium
Vagus neck branches
- Superior and inferior cervical cardiac branches
- Right RLN
Vagus thoracic branches
- Left RLN
- Thoracic and cardiac branches
Histological structure of the oesophagus
- Mucosa = non-keratinised stratified squamous epithelium
- Submucosa = glandular tissue
- Muscularis externa
- Adventitia
(5. Loose connective tissue outer covering in the thorax)
Where does the thoracic aorta commence
Left side of the body of T4
Outline the course of the thoracic aorta
- Begins at T4
- Descends down the left side of T5-12 (surrounded by aortic plexus)
- Lies posterior to the root of the right lung, pericardium, oesophagus
- Passes through aortic hiatus with thoracic duct and azygous vein on its right side
Where is the thoracic duct situated
Lies on the anterior aspect of the bodies of the inferior 7 thoracic vertebrae
Where does the thoracic duct conduct lymph from
- Lower limbs
- Pelvic cavity
- Abdominal cavity
- Left upper limb
- Left side of the thorax
- Head and neck
Where does the thoracic duct originate
Cisterna chyli
Describe the course of the thoracic duct
- Originates at cisterna chyli
- Ascends through aortic hiatus of diaphragm
- Ascends through posterior mediastinum
- Aorta on its left
- Azygous vein on its right
- Oesophagus anteriorly - Crosses to the left under oesophagus to ascend superior mediastinum
- Drains into venous system near union of left IJV and subclavian veins