Thorax anatomy Flashcards
Where is the caval opening located?
T8, central tendon of diaphragm
What structures pass through caval opening?
IVC + right phrenic nerve
Where is oesophageal hiatus located?
Right crus diaphragm, T10
What structures pass through oesophageal hiatus?
Oesophagus, posterior and anterior vagal trunks, oesophageal branch left gastric artery
How is aortic hiatus formed? What level is it at?
R and left crura and median arcuate ligament. T12
What passes through aortic hiatus?
Aorta, azygous vein, thoracic duct
Describe venous drainage of anterior chest wall
Anterior: anterior intercostal veins –> internal thoracic vein–> brachiocephalic vein
Describe venous drainage of upper 4 intercostal spaces posterior chest wall
Drained by azygous system into SVC
-1st space: B/l highest (supreme) intercostal vein –> brachiocephalic vein
-2nd-4th: posterior intercostal veins – superior intercostal vein
-R side: superior intercostal vein –> azygous vein
-L side: Superior intercostal vein –> accessory hemiazygous or brachiocephalic vein
Drainage of posterior 5-12 intercostal spaces posterior chest wall
Drained by azygous system into SVC
L side:
–> 5-8 drained by accessory hemiazygous
–> 9-11 hemiazygous vein
–> accessory hemiazygous +hemiazygous–> azygous –> SVC
R side:
-5-11: Azygous vein
How is venous drainage to chest wall divided?
Anterior
Posterior
–> upper 4 ( R + L)
–> 5-11 (R + L)
What is arterial supply of diaphragm?
Superior surface:
-internal thoracic
—>pericardiophrenic artery
—->musculophrenic arteries
-Descending thoracic aorta
—> superior phrenic
Inferior surface
-Abdominal aorta –> inferior phrenic arteries
Describe lymphatic drainage of breast
General rule:
-75% Lateral breast–> ipsilateral axillary nodes: anterior axillary nodes + central axillary nodes –> apical axillary nodes
-Medial breast –> Internal thoracic nodes
However: valveless channels connecting systems allow flow in both directions
Lymph also flows to:
-Infraclavicular + supraclavicular nodes
-Subscapular + interpectoral nodes
-Contralateral breast
Arteries supplying anterior chest wall
1-6: Internal thoracic –> anterior intercostal arteries
7-9: musculophrenic –> anterior intercostal arteries
Arteries supplying anterolateral chest wall:
Axillary artery –> superior + lateral thoracic
Below 12th rib:
–> descending thoracic aorta –> subcostal
Arteries supplying posterior chest wall
1 + 2: subclavian –> costocervical trunk –> superior intercostal arteries –> posterior intercostal arteries
3-12: Descending thoracic aorta –> posterior intercostal arteries
Arteries supplying chest wall
Arteries supplying anterior chest wall
-1-6: Internal thoracic –> anterior intercostal arteries
-7-9: musculophrenic –> anterior intercostal arteries
Arteries supplying anterolateral chest wall
-Axillary artery –> superior + lateral thoracic
-Below 12th rib:
–> descending thoracic aorta –> subcostal
Arteries supplying posterior chest wall
-1 + 2: costocervical trunk–> posterior intercostal arteries
-3-12: Descending thoracic aorta –> posterior intercostal arteries
What is the origin and insertion of pec minor?
Origin: 3rd-5th ribs (near costal cartilages)
Insertion: medial border + superiro surface coracoid process of scapula
What is innervation of pec minor?
Medial pectoral nerve (C8-T1)
What is the action of pec minor?
–> Stabilises scapula by drawing it inferiorly + anteriorly against thoracic wall
–> raises ribs on inspiration
What are the branches of the left and right coronaries?
Left
-LAD
-Left marginal
-Left circumflex
Right
-Right marginal anteriorly
-Posterior interventricular posteriorly (left in 25% of patients)
What territory is supplied by RCA?
R atrium + most of R ventricle, SA (60%) + AV (20%) nodes + posterior 1/3rd interventricular septum + diaphragmatic surface left ventricle
What territory is supplied by right marginal?
Right ventricle
Apex
Left anterior descending territory
Right ventricle, left ventricle, anterior 2/3rd IVS
Left marginal territory
Left ventricle
Left circumflex territory
Left atrium + ventricle
What does left coronary supply?
left atrium/ventricle, IVS, AV node branches
Posterior descending territory:
R ventricle, L ventricle, posterior 1/3rd IVS
What is the arterial supply to the oesophagus?
Arterial supply is segmental
Cervical part: Subclavian–> thyrocervical trunk–> inferior thyroid
Thoracic part: Branches from descending thoracic aorta
Abdominal part: oesophageal branch L gastric + inferior phrenic
Describe venous drainage of oesophagus
Cervical: inferior thyroid
Thoracic: azygous, hemiazygous, accessory azygous
Abdominal: Azygous + left gastric
Name important anatomical structures at level of manubriosternal junction
-SVC entering right atrium
-Bifurcation of trachea
-Bifurcation of pulmonary trunk
-Arch of aorta
-Thoracic duct crosses from right to left mediastinum
-L recurrent laryngeal nerve hooks around aortic arch
Innervation of diaphragm
Motor supply: phrenic nerves C3-C5
Sensory:
–> Central: phrenic nerve c3-5
—> Peripheral: Intercostal nerves T5-T12
Arterial supply to breast
1) Internal thoracic –> medial mammary perforating + anterior intercostal branches
2) Axillary –> Lateral thoracic + thoracoacromial arteries
3) Thoracic aorta –> posterior intercostal arteries
What is first branch of ascending aorta?
Coronary arteries
What is the origin of right and left coronary arteries?
L + R aortic sinus
What territory does R coronary artery supply?
-All surfaces R atrium
-25-30% right ventricle
-Inferior wall right ventricle
-SA node 60% + AV node
What territory does L coronary supply?
-L atrium
-Most of L ventricle
-Part of R ventricle
-Most of interventricular septum
-SAN in 40%
What territory does L coronary supply?
-L atrium
-Most of L ventricle
-Part of R ventricle
-Most of interventricular septum
-SAN in 40%
What is the action of pec major?
Clavicular head: flexes + adducts arm
Sternal head: Adducts and medially rotates arm, accessory muscle of inspiration
What is origin and insertion of pec major?
Origin
-Clavicular head: anterior border medial 1/2 of clavicle
-Sternocostal: anterior surface of sternum, superior 6 costal cartilages
Insertion
-Lateral lip bicipital groove of humerus
What is innervation of pec major?
Clavicular head: C5-C6 (lateral pectoral nerve)
Sternocostal head: C7-T1 (medial pectoral nerve)
What is the contents of the superiro mediastinum?
PVT Left BATTLE
Phrenic nerve
Vagus nerve
Thoracic ducts
Left recurrent laryngeal
Brachiocephalic vein
Aortic arch
Thymus
Trachea
Lymph node
Oesophagus
What are the contents of middle mediastinum
Vessels: ascending aorta, lower 1/2 SVC, Azygous vein, pulmonary arteries + veins
Nerves: Phrenic nerves
Viscera: Heart + Pericardium, tracheal bifurcation
Others: bronchial lymph glands
What are the contents of the posterior mediastinum?
on the DATE Vivian Slapped Larry
Descending thoracic aorta
Azygous/hemiazygous vein
Thoracic duct
Esophagus
Vagus nerve
Splanchnic nerves
Lymphatics
Vessels: thoracic part of descending aorta, azygous and hemiazygous veins
Nerves: Vagus + splanchnic nerves (arising from sympathetic trunk to supply viscera in thorax + abdomen)
Viscera: oesohpagus
Others: Lymph nodes + thoracic duct
What are the branches of subclavian artery?
1st part medial to anterior scalene, 2nd behind, 3rd lateral
VITCD
1st part
–> vertebral artery
–> Internal thoracic artery
–> Thyrocervical trunk
2nd part
–> Costocervical trunk and dorsal scapular artery
3rd part
–> No branches (occasionally dorsal scapular)
Name layers gone through when inserting chest drain
Superficial to deep:
Skin
Subcut fat
Deep fascia
Serratus anterior
External intercostal muscles (infero-anterior orientation of fibres)
Internal intercostal (infero-posterior) lateral part intercostal space only
Innermost intercostal -lateral part intercostal space only
Endothoracic fascai
Parietal pleura
What is a bronchopulmonary segment?
1) Segment of lung
2) Segmental/tertiary bronchus
3) Segmental branch tertiary arteries
4) Segment of lung tissue
5) Surrounding connective tissue septum
How many bronchopulnonary segments does each lung have?
Right has 10
–> upper lobe 3, middle 2, lower 5
L has 10
–> upper + lower 5 each
What are the boundaries of the posterior mediastinum?
Anterior: pericardium
Inferior: diaphragm
Posterior: Thoracic vertebrae
Lateral: mediastinal pleura
Roof: line from sternal angle + T4 vertebra
Describe musculature of the oesophagus
2 planes: external longitudinal fibres + internal circular
upper 1/3rd: Striated
Middle 1/3rd: mixture of striated and smooth
Lower 1/3rd: smooth muscle
Where does the breast lie anatomically?
Base of breast:
–> sternum to mid-axillary line
–> 2nd-6th rib
2/3rd medially overlies pec major
1/3rd laterally overlies serratus anterior
What is the blood supply to the breast?
Mainly lateral thoracic
Also:
–> internal thoracic
–> Thoraco-acromial
–> posterior intercostals
How does right bronchus differ from left?
-Right is shorter, wider and more vertical
-Therefore foreign bodies preferentially go down right main bronchus
-Material aspirated by supine/anaesthetised pt also gravitates to apical part of right lung: common site for aspiration pneumonia/abscess
What is the superior limit of pleura? What is the clinical significance of this?
2.5cm above medial 1/3rd clavicle
Does not extend above 1st rib
Injuries above clavicle (e.g. central line) can involve pleura
—> pneumothorax
What is the lower border of pleura?
Extends below medial border 12th rib, behind upper border of kidney
Structures at hilum
-Bronchus is posterior, artery always superior, vein inverior
-BAV: bronchus, artery, vein
Relations of lungs
Right: SVC, oesohpagus, azygouis
Left: Aorta, heart, oesophagus
Both
-Diaphragm
How do you orientate side of lungs?
-Diaphragm faces down
-Thinner sharper border faces forwards
Branches axillary artery
Semen tastes like sweet apple pie
Superiro thoracic
thoraco-acromial
Lateral thoracic
Subscapular
Anterior circumflex humeral
Posterior circumflex humeral
Describe venous drainage of chest wall
Anterior: anterior intercostal veins –> internal thoracic vein–> brachiocephalic vein
Upper 4 spaces posterior:
Drained by azygous system into SVC
-1st space: B/l highest (supreme) intercostal vein –> brachiocephalic vein
-2nd-4th: posterior intercostal veins – superior intercostal vein
-R side: superior intercostal vein –> azygous vein
-L side: Superior intercostal vein –> accessory
5-12 posterior chest wall:
Drained by azygous system into SVC
L side:
–> 5-8 drained by accessory hemiazygous
–> 9-11 hemiazygous vein
–> accessory hemiazygous +hemiazygous–> azygous –> SVC
R side:
-5-11: Azygous vein
