A16 & 17: Thorax Flashcards
What is the cranial boundary of the thoracic cavity?
The thoracic inlet
What is the caudal boundary of the thoracic cavity?
Diaphragm
What are the lateral boundaries of the thoracic cavity?
The ribs, costal cartilage & intercostal muscle.
What is the ventral boundary of the thoracic cavity?
Sternum
What is the dorsal boundary of the thoracic cavity?
Thoracic vertebrae.
Which structures pass through the thoracic inlet in a normal dog?
Oesophagus, trachea, vagosympathetic trunk, carotid artery & jugular vein.
Which structures pass through the thoracic inlet in a dog with BOAS?
Oesophagus, trachea, vagosympathetic trunk, carotid artery & jugular vein + right lung.
Which lobe of the left lung has 2 parts?
The cranial lobe has cranial & caudal parts.
How many lobes does each lung have?
Left lung has 2 lobes
Right lung has 4 lobes
What are the lobes of the right lung?
Cranial lobe
Caudal lobe
Middle lobe
Accessory lobe
What is special about the accessory lobe’s location?
It is deep and sometimes protrudes on the left side.
What are the 3 branches of the aortic arch?
Ascending aorta
Brachiocephalic trunk
Left subclavian artery
What are the 3 branches of the brachiocephalic trunk?
Right subclavian artery
Right common carotid artery
Left common carotid artery
What are the 4 branches of each of the subclavian arteries?
Costocervical a.
Vertebral a.
Cervical a.
Internal thoracic a.
What are the 2 branches of the cranial vena cava?
Right and left brachiocephalic veins.
What do each of the brachiocephalic veins branch into?
Subclavian vein (left or right)
Internal jugular vein (left or right)
External jugular vein (left or right)
What is the role of the thoracic duct?
It collects the drainage from lymphatic capillaries from the abdominal cavity & hindlimbs.
What does the thoracic duct drain into?
Left brachiocephalic vein
Where is the thoracic duct located?
Between the dorsal border of the aorta & the ventral border of the azygous vein.
What happens to the left and right vagus nerves once they have passed the diaphragm?
They are no longer left and right but ventral and dorsal branches.
Which nerve is given off by the vagus nerve?
Recurrent laryngeal nerve
Where do the phrenic nerves arise from?
Cervical nerves 5-7
What do the phrenic nerves innervate?
Diaphragm
What do the recurrent laryngeal nerves innervate?
The laryngeal muscles
What vessel does the left recurrent laryngeal nerve wind around ?
The aortic arch
What vessel does the right recurrent laryngeal nerve wind around?
Right subclavian artery.
State the lymph nodes present in the thorax.
Cranial mediastinal lymph node
Tracheobronchial lymph node
Sternal lymphe nodes
Where is the cranial mediastinal lymph node located?
RHS, near cranial vena cava.
Where is the tracheobronchial lymph node located?
Near bronchi
Where are sternal lymph nodes located?
Near the sternum
What is the thymus?
An unpaired bilobed organ that plays a role in the immune system.
Where is the thymus located?
Between the thoracic inlet & the heart
What is a particularity of the thymus?
It is quite large when the animal is young and gets atrophied to adipose tissue as the animal gets older.
What is the function of the diaphragm?
It serves as a division between the thoracic & abdominal cavities and it is involved in respiration.
What is the diaphragmatic cupula?
The domed part of the diaphragm
What are the sternal attachements of the diaphragm?
The dorsal surface of the sternum, cranial to the xiphoid cartilage.
What are the costal attachements of the diaphragm?
The medial surfaces of ribs 8-13
What are the lumbar attachements of the diaphragm?
The transverse processes of the 3rd & 4th lumbar vertebrae. It is attached by the left & right crura.
What are the 3 foramina of the diaphragm?
Aortic hiatus
Oesophageal hiatus
Caval foramen
What structures pass through the aortic hiatus?
Aorta, azygous vein, thoracic duct & sympathetic trunk
What structures pass through the oesophageal hiatus?
Oesophagus & vagus nerves.
What structures pass through the caval foramen ?
Vena cava.
What is the blood supply of the diaphragm?
Phrenic arteries
What is the name of the serous membrane of the thoracic cavity?
Pleura
What separates the left and right pleural cavities?
The mediastinum
What is the cupula pleura?
Where costal pleura reflects to become mediastinal pleura.
What is the costodiaphragmatic recess?
The region between the line of pleural reflection & the basal borders of the lungs.
What is the line of pleural reflection?
Where costal pleura reflects to become diaphragmatic pleura.
What is the pulmonary ligament?
Where pulmonary pleura reflects into mediastinal pleura between the caudal lobe of the lung & mediastinal pleura.
What is costal pleura?
Parietal pleura that covers the ribs
What is mediastinal pleura?
Pleura covering the mediastinum
What is pulmonary pleura?
Visceral pleura covering the lungs
What is diaphragmatic pleura?
Parietal pleura that covers the diaphragm
What is pericardium?
The heart’s serous membrane
What is particular about the pericardium?
It is double layered.
What are the layers of pericardium?
Visceral serous pericardium
Pericardial cavity
Visceral parietal pericardium
Fibrous pericardium
What is fibrous pericardium attached to?
Visceral parietal pericardium & mediastinal pleura
What is the name of the visceral serous pericardium?
Epicardium
What is the mediastinum?
The space between the left and right pleural cavities.
What forms mediastinum?
The left and right mediastinal pleura.
What does the mediastinum contain?
All the structures of the thoracic cavity except the lungs & diaphragm.
What are the divisions of mediastinum?
Cranial mediastinum –> cranial to heart
Middle mediastinum –> level of heart
Caudal mediastinum –> caudal to heart.
Which muscles are involved in inspiration?
Scalenus, serratus dorsalis cranialis, rectus thoracis, external & internal intercostal muscles.
Also diaphragm
Which muscles are involved in expiration?
Serratus dorsalis cranialis & internal intercostal muscles
