Thorax Flashcards
Mediastinum
Separated into 4 Superior mediastinum Anterior mediastinum Posterior mediastinum Middle mediastinum
Superior mediastinum - borders
Superior: thoracic inlet
Inferior: sternal angle
Anterior: Manubrium
Posterior: thoracic body
Content of superior mediastinum
Arch of aorta/branches
SVC/brachiocephalic vein - azygos, superior intercostal, supreme intercostal veins
trachea, oesophagus, thymus
phrenic nerve - anterior to hilum of lungs
vagus nerve - right one parallel to trachea posterior to SVC; left one anterior to arch but posterior to bronchus
Anterior mediastinum - borders
Superior - sternal angle
Inferior - diaphragm
anterior - body of sternum (T1-T4)
posterior - pericardium
Anterior mediastinum - content
Phrenic nerves
Thymus
Lymph nodes
Thymus
3rd pharyngeal pouch
immunological organ, diminish in size after puberty
Supply - internal thoracic artery
THYMIC APLASIA in DiGeorge syndrome
Posterior mediastinum - borders
Superior - sternal angle
inferior - diaphragm
anterior - pericardium
posterior - thoracic verterbral body (T5-12)
Posterior mediastinum - contents
Descending aorta (T12) posterior intercostal, bronchial, oesophageal, superior phrenic arteries Azygos/hemiazygos/accessory azygos veins Thoracic duct oesophagus vagus nerve sympathetic trunk
middle mediastinum - content
Heart Aortic root pulmonary trunk SVC Hilum/bronchus lymph nodes cardiac plexus
Thoracic spine
Demifacets - to articulate with head of ribs
Costal facet - to articulate with tubercles of ribs
Costotransverse ligaments
Radiate ligaments of head of rib
Muscles of the thorax
Intercostal - external, internal, innermost Transversus thoracis Subcostals Pectoralis major/minor Serratus anterior
external intercostal
runs inferioanteriorly from lower of border of rib to superior border of rib below
ELEVATES rib
Internal intercostal
runs inferioposteriorly from rib above to rib below
DEPRESSES rib
innermost intercostal
separated by internal by neurovascular bundle
medial edge of costal groove to superior border of rib below
Transversus thoracis
posterior surfave of sternum to costal cartilage 2-6
depressed the ribs
Diaphragm
Innervated by phrenic nerve C3-C5
arises from right & left crura
right crus - L1-L3; act as the physiological sphincter of oeseophagus
Left crus - L1-2
3 attachments - lumbar vertebrae & arcuate ligaments; costal cartilage ribs 7-12; xiphoid process of sternum
supplied by superior phrenic and inferior phrenic (aorta)
opening of diaphragm
T8 - IVC, right phrenic nerve
T10 - oesophagus, vagus nerve, oesophageal branches of left gastric
T12 - aorta, thoracic duct, azygos vein
Breast - surface anatomy
lateral border of sternum to midaxillary line
2nd to 6th costal cartilage
Circular body - nipple, areolae
Axillary tail
Anatomical structure of the breast
mammary glands - lobules drain to lacterous duct
connective tissue stroma - suspensory ligament of cooper
pectoral fascia - separates it from pectoralis major
Blood supply & lymphatics of breast
Supplied internal thoracic artery mainly but also from lateral thoracic and thoracoacromial arteries (axillary artery) and lateral mammary branches (intercostal)
Lymphatics drains into axilla, parasternal, posterior intercostal
Skin above drains into axillary, inferior deep cervical/infraclavicular nodes
Pleura - surface anatomy
2.5cm above at medial third of clavicle midline at 2nd rib left - diverges at 4th rib right - diverges at 6th rib midclavicular line - 8th midaxillary line - 10th posterior - 12th
Pleura - structure
Mesothelial cells, serous membrane, both layers are continuous at the hilum
Parietal - internal surface of thoracic wall,
Visceral - covers the lungs
Surface anatomy of the lung
2.5cm above at medial third of clavicles hila lies at level of 3/4 ribs mid clavicular line at 6th rib midaxillary line at 8th rib posterior at 10th rib
Anatomy of lung
right - 3 lobes
left - 2lobes + lingular
Has pulmonary arteries, veins and bronchial arteries and veins
Nerve - pulmonary plexus
parasympathetic - vagus, secretion from glands
sympathetic - dilatation of smooth muscles
Hilum - bronchus posterior to artery & vein
Tracheobronchial tree
C-shaped with trachealis muscles
pseudostratified columnar epithelium and goblet cells
Right bronchus - wider, shorter, straight down
Bronchus divides into lobar bronchi then to segmental bronchi - bronchopulmonary segments
Bronchopulmonary segments
individual units of lung (has its own artery, vein, lymphatics)
right side - 10 segments
upper - 3 = apical, anterior, posterior
middle - 2 = lateral and medial
lower - 5 = apical, anterior, posterior, medial, lateral
left side = 8-9 segments
upper - 2 = apico-posterior, anterior
lingular - 2 = inferior and superior
lower - 4 = superior, anteromedial, posterior, lateral
Bronchioles
no cartilage nor goblet cells
simple cuboidal epithelium with club cells that produce surfactant lipoprotein (reduces compliance)
at the end divides into alveoli (simple squamous epithelium) type 2 alveolar cells secretes surfactant in alveoli
Pericardium
Fibrous - fixes the position and protect from infection
Serous - parietal and visceral layer with serous fluid inside, lubricates the motion of the heart
Transverse pericardial sinus - results of the embryological folding of the heart tube, divides the venous and arterial vessels
Innervated by phrenic nerve
Surface anatomy of the heart
Superior - right 3rd costal cartilage and left 2nd ICS
right side - down to 6th costal cartilage
apex - 5th ICS at midclavicular line
right border formed by right atrium
left border formed by left atrium and ventricle
Right atrium
receives blood from IVC/SVC and coronary veins/sinus
2 sections separated by crista terminalis
sinus venarum - smooth due to sinus venosus
atrium proper - rough due to pectinate muscles
Fossa ovalis - remnant of foramen ovale
originally formed by septum primum with ostium primum then by spetum secundum and ostium secondum
Left atrium
Receives blood from pulmonary veins
posterior aspect of the heart
Inflow portion - smooth from pulmonary vein
outflow portion - pectinate muscles from embryonic atrium
Right ventricle
Pumps towards pulmonary trunk
anterior border of the heart
Inflow portion - trabeculae carnae = ridges, bridges, pillars (papillary muscles - attached to chordae tendineae)
outflow - conus arteriosus
Left ventricle
Pumps outwards to the aorta
forms the apex of the heart
inflow - trabeculae carnae
outflow - aortic vestibule
Atrioventricular valves
Tricuspid - 3 valves
Mitral - 2 valves
attached to chorda tendineae which is attached to papillary muscles
Semilunar valve
Pulmonary valve - 3 cusp
Aortic valve - 3 cusp
left anterior and posterior aortic sinus, where left has Left coronary artery and anterior has right coronary artery
Conduction of the heart
SAN - AVN - Bundle of His - Purkinje fibres
SAN is found at the crista terminalis where the SVC opens in
AVN is in the intraventricular septum - triangle of Koch
Coronary arteries
LCA - LAD (anterior interventricular groove) then left marginal & circumflex
RCA (coronary sulcus) - Right marginal & posterior interventricular
Cardiac veins
Great cardiac follows LAD then into coronary sinus
small cardiac follows RCA then into coronary sinus
middle cardiac, left marginal, left posterior veins joins the coronary sinus
Layers of the heart
Endocardium
Myocardium
Epicardium
Endocardium
innermost layer
lies the cavities and valve of the heart
loose connective tissue with simple squamous epithelial tissue
regulates contraction
Subendocardial layers has purkinje fibres
myocardium
involuntary striated muscles
epicardium
visceral layer of serous pericardium
simple squamous epithelial cells
