Thorax and Thoracic Viscera Flashcards
What are the cavities within the thoracic cavity?
Left pleural, right pleural, and pericardial
What are the boundaries of the thoracic cavity?
Dorsal - thoracic vertebrae
Lateral - ribs and costal cartilages
Ventral - sternebrae and costal cartilages
Where does the diaphragm attach to the ribs?
At right and left costal parts
Where does the diaphragm attach to the sternum?
At the sternal part
What attaches the diaphragm to the lumbar vertebral bodies?
Right and left crural tendons, dorsally located
What is the central tendon?
All muscular components attach to this centrally located, trefoil-shaped tendon
What is the diaphragmatic line of pleural reflection?
The junction between the costal pleura and the diaphragmatic pleura
What is included in the plica venae cavae?
This fold of the right mediastinal pleura envelops the caudal vena cava and right phrenic nerve
What is the lumbocostal arch?
Area between the crura and the vertebrae; major splanchnic nerve passes through here, though it’s not a true opening; POTENTIAL AREA OF HERNIATION
What passes through the aortic hiatus?
The aorta, azygous vein, and thoracic duct
What passes through the esophageal hiatus?
The esophagus and dorsal and ventral vagal trunks
What passes through the caval foramen?
The caudal vena cava
What is the costodiaphragmatic recess?
The junction where the costal pleura reflects onto the surface of the diaphragm; a “pocket” is generated here
What is the lumbodiaphragmatic recess?
The region where the pleura extends ventrally form the caudal and dorsal thoracic wall (at the lumbar region) to the crura of the diaphragm; spans the lumbocostal arch; POTENTIAL AREA OF HERNIATION
What does the internal thoracic a. continue as?
The musculophrenic a.
What type of innervation is found in the phrenic nerves?
Somatic –> skeletal muscle
Where are parietal serous membranes found?
Lining the walls of a cavity
Where are visceral serous membranes found?
Covering organ surfaces
What is parietal pleura?
Where the two pleural sacs are adherent to the walls of the thoracic cavity and to the mediastinum
What is the endothoracic fascia?
The underlying connective tissue “glue” that attaches the parietal pleura to the thoracic walls
What are the pleural cavities?
The spaces within the pleural sacs; these are separate from each other and from the thoracic cavity
What is the mediastinum?
The space between the two pleural sacs where they meet medially within the thoracic cavity; continuous with the cervical visceral space
What is the costal (parietal) pleura?
Where the pleura is in contact with the ribs and costal cartilages
What is the sternal (parietal) pleura?
Where the pleura is in contact with the sternum
What is diaphragmatic (parietal) pleura?
Where the pleura is in contact with the diaphragm
What is the mediastinal (parietal) pleura?
Located where the left and right pleural sacs meet centrally within the thorax
What is the pericardial mediastinal pleura?
The mediastinal pleura that is in direct contact with the pericardium
What is the pleural cupula?
Located at/near the thoracic inlet where the pleura reflects from the costal wall to the cranial mediastinum; may extend into the cervical visceral space
What are the species differences of the pleural cupula?
Dog: left extends further cranially than the right
Large animals: right extends further cranially and into CVS where it’s susceptible to puncture wounds at the base of the neck and subsequent collapse of the right lung
What is the costomediastinal recess?
Located at the junction where the costal pleura reflects from the ventral thoracic wall and extends dorsally on either side of the mediastinum; bilateral
What is the mediastinal recess?
A recess located between the right mediastinal pleural and the plica venae cavae; the accessory lobe of the right lung is located within this recess
What is the visceral pleura?
The mesothelium that covers the lungs; is continuous with the parietal pleura
What is the fibrous pericardium?
The continuation of the endothoracic fascia as it extends from the surface of the diaphragm; the middle layer of the pericardial sac
What is the phrenicopericardial ligament?
The continuation of the fibrous pericardium to the diaphragm forms this in the dog/cat
What is the sternopericardial ligament?
The continuation of the fibrous pericardium to the diaphragm forms this in the horse/ox
What is the parietal pericardium?
Innermost layer of the pericardial sac; a serous membrane lining the walls of the pericardial cavity
What is the pericardial mediastinal pleura?
The outermost layer of the pericardial sac; this region is in direct contact with the pericardium
If you were to shoot an arrow through the heart, what is the order of the layers the arrow would pass through?
Pericardial mediastinal pleura –> endothoracic fascia/fibrous pericardium –> parietal pericardium –> visceral pericardium/epicardium
What are the structures within the mediastinum?
Trachea Esophagus Aorta Lymphatic structures Thymus Right and left vagus nerves/dorsal and ventral vagal nerve trunks Right and left recurrent laryngeal nerves Right and left phrenic nerves Pericardium and heart
What is the trachealis muscle?
Completes the cartilaginous rings of the trachea dorsally
What are the principal bronchi?
Originate where the trachea bifurcates
What is the carina?
The partition between the left and right principal bronchi at their origin from the trachea
What are the lobar bronchi?
Branch from the principal bronchi and supply the lobes of the lung; the lobation of each lung is determined by the lobar bronchi
What are the segmental bronchi?
Branch from the lobar bronchi and supply bronchopulmonary segments, which are separated from the rest of the lung by a connective tissue septum
What are the bronchioles?
Branches of the segmental bronchi which ultimately terminate as respiratory bronchioles; exchange portion of respiratory system begins here
What is the functional blood supply to the lungs?
Pulmonary arteries and veins
What is the nutritional blood supply to the lungs?
Bronchoesophageal artery and azygous vein
Which species does not have external lobations in the lungs?
The horse; they are very evident in bovine and porcine
What is the tracheal bronchus?
A bronchus that branches directly from the trachea cranial to the cranial bifurcation that supplies the cranial lobe of the right lung of ruminants
