Intercostal Muscles Flashcards
Where are the intercostal muscles located?
Between the ribs
External intercostal are …. To the internal intercostals
They are superficial (closer to the surface) to the internal intercostals
What is the deepest type of intercostal muscles?
The innermost intercostals
How many sets of intercostals are there?
11 sets of each
How does venous drainage occur?
Occurs via the intercostal veins
What are the intercostal veins innervated by?
By the intercostal nerves
What is the intercostal neurovascular bundle?
The intercostal artery, vein and nerve travel together in the intercostal space
Where does the intercostal neurovascular bundle lie?
They lie at the lower border of each rib
Where do external intercostal muscles extend from?
The lower border of the rib to the upper board of the rib below
Where do external intercostals run?
Around the wall of the thorax -
When do the external intercostals end?
They end anteriorly in thin membranes called the anterior (external) intercostal membranes which continue forward to the sternum
What do the external intercostals do?
They pull the ribs upwards and forwards during inspiration causing an increase in both the lateral and anteroposterior diameters of the thorax
Where are the internal intercostal muscles found?
Between the most inferior lateral edge of the costal grooves of the ribs to the superior margins of the ribs below
Where do the internal intercostals begin?
At true ribs (1-7) and at the edge of the cartilages of the false ribs (8-12)
What’s the membrane called that the internal intercostals reach?
The posterior (internal) intercostal membranes
What happens to the internal intercostal muscles during inspiration?
They pull the ribs down and inward during active respiration
What are the innermost intercostal muscles described as?
Incomplete and variable
Describe the innermost intercostals
They pass from the rib to deep into the internal intercostals. Their fibres run in the same direction as the internal intercostals
What are the innermost internal intercostals separated by?
The bundle of intercostal blood vessels and nerves
What muscles assist in the expansion of the thoracic cavity to maximise the respiratory efficiency but DO NOT have functions that are related to breathing?
Sternocleidomastoid, pectoral is minor and the scalene muscles
