What are the contents of the thoracic cavity?
Heart Lungs Thymus Distal part of trachea Esophagus
What forms the thoracic cage?
the thoracic skeleton
What separates the ribs and their costal cartilages?
the intercostal cartilages
What structure allows for communication between the thoracic cavity and the neck+upper limb?
Superior Thoracic Aperture (the anatomical thoracic inlet)
What are the boundaries of the Superior Thoracic Aperture?
Posteriorly by the T1 vertebra
Laterally by the first pair of ribs and their costal cartilages
Anteriorly by the superior border of the manubrium
What structure allows for communication between the thoracic cavity and the abdomen?
Inferior Thoracic Aperture (the anatomical thoracic outlet)
What structure closes the inferior thoracic cavity and separates the thoracic and abdominal cavities?
Diaphragm
What are the boundaries of the Inferior Thoracic Aperture?
Posteriorly by the T12 vertebra
Posterolaterally by the the 11th and 12th pairs of ribs
Anteriolaterally by the joined costal cartilages of ribs 7-10 forming the costal margin
Anteriorly by the xiphisternal joint
What are the 3 types of ribs and what defines them?
True Ribs (vertebrosternal): attaches to the sternum anteriorly through their own costal cartilages False Ribs (vertebrochondral): have cartilages on the anterior ends that are joined to the cartilage of the rib and so their connection to the sternum is indirect Floating Ribs (Free): the cartilages on the anterior surface of these ribs cannot attach to the sternum at all
Which ribs are considered true ribs?
1st to 7th ribs
Which ribs are considered false ribs?
8th to 10th ribs
Which ribs are considered floating ribs?
11th and 12th ribs and sometimes 10th rib
What separates the superior and inferior articular facets on a typical rib?
Crest of head
What does the smooth articular part of the tubercle on a typical rib articulate with?
corresponding transverse processes of the vertebra
What attaches at the rough non articular part of the tubercle on a typical rib
the fibrous attachment of the process via the costotransverse ligament
Where is the costal groove located on a typical rib?
on the inferior edge of the body of the rib
What is the purpose of the costal groove?
protects the intercostal nerves and vessels
What are the atypical ribs?
1st, 2nd, and 10th-12th
What does the scalene tubercle separate on the 1st rib?
2 shallow horizontal grooves for the subclavian vessels
What is atypical about the 1st rib?
it is broad and its body is widest and its cross section is more horizontal
What is atypical about the 2nd rib?
it is thinner and it has formations for the attachment of the serratus anterior and posterior scalene muscles
What is atypical about the 10th-12th ribs?
they only have 1 facet on their heads
What is atypical about the 11th and 12th ribs?
they are short have no necks or tubercles
What is the purpose of the costal cartiages?
prolong the rib anteriorly and contribute to the elasticity of the thoracic wall