Thoracic anatomy Flashcards
week 1
What are the joints between vertebrae and ribs and what is their function?
Costotransverse
Costverterbral
Elevation + depression
What is the thoracic cage?
The thoracic cage is skeletal.
What is the thoracic wall?
The thoracic wall is muscular.
What is the thoracic cavity?
The thoracic cavity is internal.
What is the function of the superior thoracic aperture?
The superior thoracic aperture allows communication between the thorax, head, neck, and upper limbs.
What is the function of the inferior thoracic aperture?
The inferior thoracic aperture allows communication between the thorax, pelvis, and lower limbs.
What are the boundaries of the superior thoracic aperture?
The boundaries are the manubrium, 1st pair of ribs, and T1.
What are the boundaries of the inferior thoracic aperture?
The boundaries are the xiphoid process, false ribs, and T12 vertebrae.
What are the functions of the thoracic cage?
The functions include protection of organs, support of the weight of upper limbs, and muscle attachment.
What structures make up the thoracic cage?
The thoracic cage is made up of the sternum, ribs, costal cartilages, and thoracic vertebrae.
What are the subclassifications of the ribs?
True ribs (1-7) articulate with the sternum, false ribs (8-10) form the costal margin, and floating ribs (11-12) do not articulate anteriorly.
What type of cartilage is costal cartilage?
Costal cartilage is hyaline.
What structures articulate via the sternocostal joints?
The upper 7 costal cartilages (true ribs) articulate with the sternum.
What are the two joints that vertebrae use to articulate?
The two joints are costovertebral (head of rib) and costotransverse (with transverse process).
What does the thoracic cage expand to in inspiration?
The thoracic cage expands vertically (diaphragm), transversely (ribs), and antero-posteriorly (sternum and true ribs).
What is Boyle’s law?
Boyle’s law states that gas pressure is inversely proportional to volume at constant temperature.
Describe the relationship between thoracic volume and pressure in inspiration and expiration.
Inspiration: increased thoracic volume (diaphragm contracts) leads to decreased pressure. Expiration: decreased thoracic volume (diaphragm relaxes superiorly) leads to increased pressure.
What are the muscles of respiration?
The muscles of respiration are the diaphragm and intercostal muscles.
What are the origins and insertions of the diaphragm?
The diaphragm originates from the xiphoid process and T12 and inserts into the central tendon.
What is the function of the diaphragm?
Contraction of the diaphragm leads to inspiration (creates negative pressure, drawing air inwards), while relaxation leads to expiration.
What innervates the diaphragm?
The diaphragm is innervated by the phrenic nerves.
What are the origins and insertions of the intercostal muscles?
The intercostal muscles originate from the inferior border of one rib and insert into the superior border of the rib below.
What is the function of the intercostal muscles?
The intercostal muscles maintain rigidity to maximize lung volume by preventing bulging or collapse.
What is the innervation of the intercostal muscles?
The intercostal muscles are innervated by the intercostal neurovascular bundle.
What nerves innervate the thoracic wall?
The thoracic wall is innervated by intercostal nerves, lateral cutaneous branch, and anterior cutaneous branch.
What dermatomes make up the thorax and abdomen?
The thorax and abdomen are made up of cervical and thoracic spinal nerves.
What nodes provide lymphatic drainage of the thoracic wall?
The lymphatic drainage is provided by parasternal nodes, intercostal nodes, and diaphragmatic nodes.
Where is the thoracic cavity entered in a thoracostomy?
The thoracic cavity is entered above the rib, usually at the 5th intercostal space and mid-axillary line.
Describe the anatomical position of the neuromuscular bundle.
The neuromuscular bundle is situated inferior to the ribs in the costal groove and lies between the internal intercostal and innermost intercostal muscles.
Where do the posterior intercostal veins drain into?
The posterior intercostal veins drain into the azygous system of veins: right side into the azygous vein and left side into the hemiazygos and accessory hemiazygos veins.
What structures provide arterial supply of the thoracic wall?
The arterial supply of the thoracic wall comes from anterior and posterior intercostal arteries.
What is the course of the anterior intercostal arteries?
The anterior intercostal arteries course from the subclavian artery to the costocervical trunk, then to the supreme intercostal artery, and finally to the superior 2 posterior intercostal arteries.
What structures provide venous drainage of the thoracic wall?
The venous drainage of the thoracic wall is provided by anterior and posterior intercostal veins.
What do the 2nd-6th intercostal nerves supply?
The 2nd-6th intercostal nerves supply the thoracic wall.
What do the 7th-11th intercostal nerves supply?
The 7th-11th intercostal nerves supply the abdominal skin and muscles.
What does the subcostal nerve supply?
The subcostal nerve supplies the skin on the anterior inferior abdominal wall.
What do the lymphatic nodes of the thoracic wall ultimately drain into?
The lymphatic nodes of the thoracic wall ultimately drain into the thoracic duct, which leads to the left brachiocephalic vein.
What parts of the body does the thoracic duct drain?
The thoracic duct drains all of the left side, as well as the right abdomen, pelvis, perineum, and lower limb.
What makes up the inferior thoracic aperture?
The inferior thoracic aperture is made up of the esophagus, aorta, inferior vena cava, thoracic duct, azygous vein, and phrenic nerve.
What makes up the superior thoracic aperture?
The superior thoracic aperture is made up of the esophagus, trachea, brachiocephalic veins, brachiocephalic artery, left common carotid artery, left subclavian artery, phrenic and vagus nerves, and apex of lungs.
What do external, internal, and innermost intercostal muscles allow for?
They keep the intercostal spaces rigid, preventing bulging or being drawn in.
What other muscles are recruited for inspiration?
Other muscles recruited for inspiration include scalenes, sternocleidomastoid, pectoralis major and minor, serratus anterior and posterior, and the levator costarum.
What other muscle is recruited for expiration?
The rectus abdominis is recruited for expiration.
Where do posterior intercostal arteries arise from?
The posterior intercostal arteries arise from the aorta at each cervical level except superiorly.
What are the two features of thoracic vertebrae that relate to the ribs?
The thoracic vertebrae have facets for articulation with the tubercle of the rib and demifacets for articulation with the head of the rib.
What is the joint between ribs and costal cartilage and what is its function?
costochondral joint (synchondroses)
flexible and expansion during inhalation
What types of joint are found in the sternocostal joints?
1st = synchros (caliginous)
2nd-7th = synovial
what are the 2 joints of the sternum and what are their classifications?
manubriosternal (symphysis)
Xiphisternal (symphysis)
