Thorax Flashcards
What is the thorax?
Region of the trunk that includes the sternum (breastbone), costal cartilages, ribs, thoracic vertebrae and the structures they enclose.
Name of cartilage that connects ribs to sternum
Costal cartilages (hyaline)
What are the boundaries of the thorax?
the superior thoracic aperture (root of neck) and inferior thoracic aperture / thoracic outlet (closed by diaphragm)
3 compartments of the thorax
left and right pleural cavities (location of lungs) and mediastinum (location of heart)
Why the superior thoracic aperture continuous with the neck?
To allow a communication between the neck and thorax for blood supply and drainage.
What structures make up the border of the superior thoracic aperture?
1st thoracic vertebrae (T1), 1st pair of ribs, manubrium
What is the name of the indent at the superior border of the manubrium?
Jugular notch
How many ribs are there?
12 pairs - 7 are true ribs, 3 are false ribs, 2 are floating ribs
Name of the structure that connects the upper limbs to the thoracic cage
pectoral girdle
What are the bones of the pectoral girdle?
Clavicle (collarbone) and scapula (shoulder bone)
3 parts of the sternum
Manubrium, body, xiphoid process
What is the sternum?
Bone that lies in the anterior midline of thorax and forms part of the ribcage.
What is the sternal angle?
Where the 2nd rib costal cartilage attaches and the manubrium articulates with the body of the sternum. The sternal angle can be palpated.
Name of the joint between rib and costal cartilage
costochondral joint
What is the space between the ribs called?
Intercostal space
Why are rib pairs 1-7 known as true ribs?
They attach directly to the sternum via their own costal cartilage
Why are rib pairs 8-10 known as false ribs?
They articulate indirectly to the sternum by connecting to the costal cartilages of the ribs above.
Why are rib pairs 11 and 12 known as floating ribs?
They do not articulate with the sternum or the costal cartilages of other ribs and instead terminate in musculature.
Why is the thorax described as being unusually shaped?
The inferior thoracic aperture, bordered by the diaphragm, has a curved, unsymmetrical shape (due to liver).
What are the intervertebral discs?
Made of fibrocartilage which compress under weight - weight bearing role
What is the mediastinum?
Area found in midline of thoracic cavity, surrounded by the left and right pleural cavities.
How is the mediastinum divided?
Superior mediastinum extends from the first rib to T4. Inferior mediastinum extends from T4 - T9 (superior to inferior) and from the sternum to pericardium (anterior to posterior). Inferior mediastinum is further divided into anterior, middle and posterior mediastinum.
Which structures are found in the superior mediastinum?
Trachea, carotid artery, aortic arch, pulmonary artery, subclavian artery, thymus.
What structures are found in the anterior mediastinum?
remnants of thymus
What structures are found in the middle mediastinum?
Heart, pericardium, ascending aorta, pulmonary trunk
What structures are found in the posterior mediastinum?
descending aorta and oesophagus
Names of great vessels
venae cava, pulmonary trunk which bifurcates into L and R pulmonary arteries, pulmonary veins (usually 2 on each side), aorta
Which vessels branch from the arch of aorta?
Brachiocephalic trunk which branches into the right subclavian and right common carotid arteries. The left common carotid artery and left subclavian artery directly branch off the aortic arch.