Thorax and Thoracic Viscera

Question 1

What are the cavities within the thoracic cavity?

Answer 1

Left pleural, right pleural, and pericardial

Question 2

What are the boundaries of the thoracic cavity?

Answer 2

Dorsal - thoracic vertebrae
Lateral - ribs and costal cartilages
Ventral - sternebrae and costal cartilages

Question 3

Where does the diaphragm attach to the ribs?

Answer 3

At right and left costal parts

Question 4

Where does the diaphragm attach to the sternum?

Answer 4

At the sternal part

Question 5

What attaches the diaphragm to the lumbar vertebral bodies?

Answer 5

Right and left crural tendons, dorsally located

Question 6

What is the central tendon?

Answer 6

All muscular components attach to this centrally located, trefoil-shaped tendon

Question 7

What is the diaphragmatic line of pleural reflection?

Answer 7

The junction between the costal pleura and the diaphragmatic pleura

Question 8

What is included in the plica venae cavae?

Answer 8

This fold of the right mediastinal pleura envelops the caudal vena cava and right phrenic nerve

Question 9

What is the lumbocostal arch?

Answer 9

Area between the crura and the vertebrae; major splanchnic nerve passes through here, though it’s not a true opening; POTENTIAL AREA OF HERNIATION

Question 10

What passes through the aortic hiatus?

Answer 10

The aorta, azygous vein, and thoracic duct

Question 11

What passes through the esophageal hiatus?

Answer 11

The esophagus and dorsal and ventral vagal trunks

Question 12

What passes through the caval foramen?

Answer 12

The caudal vena cava

Question 13

What is the costodiaphragmatic recess?

Answer 13

The junction where the costal pleura reflects onto the surface of the diaphragm; a “pocket” is generated here

Question 14

What is the lumbodiaphragmatic recess?

Answer 14

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

Question 15

What does the internal thoracic a. continue as?

Answer 15

The musculophrenic a.

Question 16

What type of innervation is found in the phrenic nerves?

Answer 16

Somatic –> skeletal muscle

Question 17

Where are parietal serous membranes found?

Answer 17

Lining the walls of a cavity

Question 18

Where are visceral serous membranes found?

Answer 18

Covering organ surfaces

Question 19

What is parietal pleura?

Answer 19

Where the two pleural sacs are adherent to the walls of the thoracic cavity and to the mediastinum

Question 20

What is the endothoracic fascia?

Answer 20

The underlying connective tissue “glue” that attaches the parietal pleura to the thoracic walls

Question 21

What are the pleural cavities?

Answer 21

The spaces within the pleural sacs; these are separate from each other and from the thoracic cavity

Question 22

What is the mediastinum?

Answer 22

The space between the two pleural sacs where they meet medially within the thoracic cavity; continuous with the cervical visceral space

Question 23

What is the costal (parietal) pleura?

Answer 23

Where the pleura is in contact with the ribs and costal cartilages

Question 24

What is the sternal (parietal) pleura?

Answer 24

Where the pleura is in contact with the sternum

Question 25

What is diaphragmatic (parietal) pleura?

Answer 25

Where the pleura is in contact with the diaphragm

Question 26

What is the mediastinal (parietal) pleura?

Answer 26

Located where the left and right pleural sacs meet centrally within the thorax

Question 27

What is the pericardial mediastinal pleura?

Answer 27

The mediastinal pleura that is in direct contact with the pericardium

Question 28

What is the pleural cupula?

Answer 28

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

Question 29

What are the species differences of the pleural cupula?

Answer 29

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

Question 30

What is the costomediastinal recess?

Answer 30

Located at the junction where the costal pleura reflects from the ventral thoracic wall and extends dorsally on either side of the mediastinum; bilateral

Question 31

What is the mediastinal recess?

Answer 31

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

Question 32

What is the visceral pleura?

Answer 32

The mesothelium that covers the lungs; is continuous with the parietal pleura

Question 33

What is the fibrous pericardium?

Answer 33

The continuation of the endothoracic fascia as it extends from the surface of the diaphragm; the middle layer of the pericardial sac

Question 34

What is the phrenicopericardial ligament?

Answer 34

The continuation of the fibrous pericardium to the diaphragm forms this in the dog/cat

Question 35

What is the sternopericardial ligament?

Answer 35

The continuation of the fibrous pericardium to the diaphragm forms this in the horse/ox

Question 36

What is the parietal pericardium?

Answer 36

Innermost layer of the pericardial sac; a serous membrane lining the walls of the pericardial cavity

Question 37

What is the pericardial mediastinal pleura?

Answer 37

The outermost layer of the pericardial sac; this region is in direct contact with the pericardium

Question 38

If you were to shoot an arrow through the heart, what is the order of the layers the arrow would pass through?

Answer 38

Pericardial mediastinal pleura --> endothoracic fascia/fibrous pericardium --> parietal pericardium --> visceral pericardium/epicardium

Question 39

What are the structures within the mediastinum?

Answer 39

``` 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 ```

Question 40

What is the trachealis muscle?

Answer 40

Completes the cartilaginous rings of the trachea dorsally

Question 41

What are the principal bronchi?

Answer 41

Originate where the trachea bifurcates

Question 42

What is the carina?

Answer 42

The partition between the left and right principal bronchi at their origin from the trachea

Question 43

What are the lobar bronchi?

Answer 43

Branch from the principal bronchi and supply the lobes of the lung; the lobation of each lung is determined by the lobar bronchi

Question 44

What are the segmental bronchi?

Answer 44

Branch from the lobar bronchi and supply bronchopulmonary segments, which are separated from the rest of the lung by a connective tissue septum

Question 45

What are the bronchioles?

Answer 45

Branches of the segmental bronchi which ultimately terminate as respiratory bronchioles; exchange portion of respiratory system begins here

Question 46

What is the functional blood supply to the lungs?

Answer 46

Pulmonary arteries and veins

Question 47

What is the nutritional blood supply to the lungs?

Answer 47

Bronchoesophageal artery and azygous vein

Question 48

Which species does not have external lobations in the lungs?

Answer 48

The horse; they are very evident in bovine and porcine

Question 49

What is the tracheal bronchus?

Answer 49

A bronchus that branches directly from the trachea cranial to the cranial bifurcation that supplies the cranial lobe of the right lung of ruminants