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)