Intercostal structures Flashcards
What makes up the thoracic wall?
Skin
Superficial fascia (anterior and lateral cutaneous branches of intercostal nerves)
Deep fascia
Muscle
What are the three instrinsic muscles of the thorax?
Pectoralis major
Pectoralis minor
Serratus anterior
What is the intercostal space?
It is the space between two ribs
What does each space contain?
Intercostal muscles
Intercostal neurovascular bundle
Lymphatics
What is the most superficial intercostal muscle of the thorax?
External intercostal muscle
What is the origin of the external intercostal muscle?`
From the lower border of the ribs above
What is the insertion of the external intercostal muscles?
Upper border of rib below
Where is the external intercostal muscle located?
Extends from the rib tubercle behind the costo-chondral junction in front
What is the external intercostal muscle replaced with anteriorly?
External intercostal membrane
What layer is the internal intercostal muscle?
Intermediate layer
What direction does the fibres of the internal intercostal muscle run?
Fibres directed downward and backward
Where is the internal intercostal muscle located?
Extends from the sternum in front to the angle of the rib behind
What is the internal intercostal muscle replaced by posteriorly?
Internal intercostal membrane
What are the three intrinsic muscles?
External intercostal
Internal intercostal
Innermost intercostal
What does the intercostal nerves supply?
Muscles of the ribs, anterolateral thorax and abdominal wall
What are the intercostal nerves?
Anterior rami of spinal nerves T1-T11 because they travel in the intercostal spaces between adjacent ribs
What is the nerve T12 called and why?
Subcostal nerve because it arises below the ribs
Do the intercostal nerves form plexuses?
No with the exception of T1
What does T1 intercostal nerve do?
Brachial plexus
What does T2 intercostal nerve do?
Innervates the intercostal muscles of the second intercostal space and is sensory for the axilla and medial surface of the arm
What does T3-T6 intercostal nerve do?
Innervate the intercostal muscles and are sensory for the anterior chest wall
What does T7-T12 intercostal nevre innervate?
the intercostal muscles, the abdominal muscles and the overlying skin.
What is present in the intercostal space?
Intercostal nerve
Intercostal artery
Intercostal vein
What are the arteries of the thoracic wall?
Thoracic aorta
Subclavian artery
Axillary artery
What are the arteries of the thoracic wall?
Thoracic aorta
Subclavian artery
Axillary artery
What does the thoracic aorta divide into?
Posterior intercostal and subcostal arteries
What does the subclavian arteries divide into?
Internal thoracic and supreme intercostal arteries
What does the axillary and superior artery divide into?
Superior and lateral thoracic arteries
What are the two intercostal arteries?
Anterior intercostal arteries
Posterior intercostal arteries
Where do the upper 6 pairs of arteries arise from?
The internal thoracic artery
Where do the 7th, 8th, 9th pairs of arteries arise from?
Musculophrenic artery
What is the origin of the internal thoracic artery?
First part of the subcalvian artery
Where does the internal thoracic artery terminate?
Opposite the sixth intercostal space by dividing into superior epigastric and musculophrenic arteries
Where does the venous drainage occur?
Parallel to the pattern of arterial supply
What is the venous drainage made up of?
Intercostal veins
Azgous vein or into internal thoracic veins
Brachiocephalic veins
What forms the internal thoracic vein?
Formed by the union of the two venae comitantes of the internal thoracic artery behind the third costal cartilage
What path does the internal thoracic vein take?
It ascends close to the artery to terminate in the corresponding innominate vein
