Thoracic Cavity Flashcards
What are the skeletal boundaries of the thoracic cavity?
Dorsal: thoracic vertebrae Ventral: sternebra and costal cartilages Lateral: ribs and costal cartilages Cranial: thoracic inlet Caudal: diaphragm
What is the diaphragm?
Provides a muscular tendinous separation between the thoracic and abdominopelvic cavities
What are the muscular portions of the diaphragm?
R & L costal parts
Sternal part
Lumbar portion with R & L crura
What are the tendinous parts of the diaphragm?
Central tendon
Right and left crura to lumbar vertebral bodies
What are the attachments/coverings of the thoracic side of the diaphragm?
Pleural covering: serous membranes of the R and L pleural cavities attach to the surface of the diaphragm
Diaphragmatic line of pleural reflection: junction between the costal pleura and the diaphragmatic pleura
Mediastinal attachment: region where the medial portions of the left and right pleural sacs attach to the diaphragm
Plica vena cavae: a fold of the right mediastinal pleura that envelopes the caudal vena cava and right phrenic nerve
What are the four openings in the diaphragm?
Lumbocostal arch
Aortic hiatus
Esophageal hiatus
Caval foramen
Lumbocostal arch
Area between the crura and vertebrae
Potential area of a hernia
Passage of splanchnic nerve
Aortic hiatus
Passage of aorta, azygous vein and thoracic duct
Esophageal hiatus
Transmits the esophagus and dorsal/ventral vagus trunks
Caval foramen
Transmits caudal vena cava
What are serous cavities?
- Line and enclose body cavities
- Composed of secretory epithelial layers (mesothelium) and a CT layer
- protective layer that secretes serous fluid to reduce friction of organs
What are the two types of serous cavities according to location?
Parietal: lines cavity wall
Visceral: cover organ surfaces
What are three serous cavities within the thoracic cavity?
Left pleural cavity
Right pleural cavity
Pericardial cavity
Parietal pleura
Where the two pleural sacs are adherent to the walls of the thoracic cavity and the mediastinum
Endothorasic fascia
The “glue” that attaches the pleura to the thoracic walls
Pleural cavities
Spaces within the pleural sacs
Mediastinum
Space between the two pleural sacs where they meet medially, continuous with the visceral space
What are the four specific regions of the parietal pleura?
Costal pleura Sternal pleura Diaphragmatic pleura Mediastinal pleura Diaphragmatic line of pleural reflection
What are the recesses of the pleura?
Pleura cupula Costomediastinal recess Costodiaphragmatic recess Mediastinal recess Lumbodiaphragmatic recess
Pleural cupula
Located at the thoracic inlet where the pleura reflects from the costal wall to the cranial mediastinum
Costomediastinal recess
At junction where the costal pleura reflects from the ventral thoracic wall and extends dorsally bilaterally
Costodiaphragmatic recess
Junction where the costal pleura reflects onto the surface of the diaphragm
Mediastinal recess
Located between the R mediastinal pleura and the plica vena cavae (accessory lobe of right lung is located here)
Lumbodiaphragmatic recess
Region where pleura extends ventrally from the caudal and dorsal thoracic walls to the crura of the diaphragm
Spans the lumbocostal arch so there isn’t a true opening
Fibrous pericardium
Dense CT sac
What does the cranial mediastinum continue as?
The cervical visceral space
What are the dorsal and ventral boundaries of the cervical visceral space?
Dorsal: longus capitis & longus coli
Ventral: sternocephalicus & sternothyrohyoideus
What are the contents of the cervical visceral space?
Esophagus
Trachea
Thyroid and parathyroid glands
Recurrent laryngeal nerves
Tracheal lymph nodes
Carotid sheath
Common carotid artery
Vagosympathetic trunk
Internal jugular veinWhat are the contents of the mediastinum?
Trachea Thymus Esophagus Phrenic nerves Vagus nerves Vagal trunk Paravertebral chain of ganglia Heart Aorta Pulmonary trunk Right azygous vein Thoracic duct Tracheobronchial lymph node
What are the three components of the pericardium?
Parietal pericardium
Fibrous pericardium
Pericardial mediastinal pleura
What are the components of the conducting system?
Trachea
Bronchial tree
What is the structure of the trachea?
Comprised of incomplete cartilaginous rings that are connected by tracheal ligaments
Trachealis muscle completes the ring dorsally
Carina
This is the partition between the right and left principal bronchi at their origin from the trachea
Principal bronchi
Left and right originate where the trachea bifurcates
Lobar bronchi
Branch from the principal bronchi and supply the lobes of the lung
Segmental bronchi
Branch from the lobar bronchi and supply bronchopulmonary segments
Bronchioles
Branches of the segmental bronchi which ultimately terminate as respiratory bronchioles (beginning of exchange system)
What makes up the respiratory bronchioles?
Alveolar duct
Alveolar sac
Alveolus
What is the functional blood supply of the lungs?
Pulmonary arteries and veins
What is the nutritive supply of the lungs?
Bronchoesophageal artery and azygous vein
How many lobes does the left lung have?
Carnivores: cranial (divided), caudal
Ruminants: cranial (divided), caudal
Horse: cranial and caudal lobe
How many lobes are in the right lung?
Carnivores: cranial, middle, caudal, accessory
Ruminants: divided cranial, middle, caudal, accessory
Horse: cranial, caudal, accessory (no middle)
Cardiac notch
Notch in the lungs where the heart rests
Where do you listen to the heart on the left side in relation to the notch?
Canine: between 3 & 4 intercostal space
Ruminants: same
Horse: between the 3 & 6 spaces
Where do you listen to the heart in relation to the cardiac notch on the right side?
Canine: within the 4 intercostal space, extends to 5
Ruminants: between 3 & 4
Horse: same
Hilus
Area of lung that is perforated by vessels, nerves and bronchi
Pulmonary ligament
Double layer of connecting pleura extending from mediastinal pleura to the visceral pleura of lungs
What is the nerve supply of the lungs?
Autonomic (SNS & PSNS)
Sensory (stretch receptors)
What are the four lymph nodes associated with the lungs?
Left tracheobronchial lymph node
Right tracheobronchial ln
Middle tracheobronchial ln
Pulmonary ln
What are the branches of the aorta?
Ascending
Aortic arch
Descending
What makes up the brachiocephalic trunk?
Left common carotid artery
Right common carotid artery
Right subclavian artery
What are the four branches of the subclavian artery?
Vertebral artery
Costocervical trunk
Superficial cervical artery
Internal thoracic artery
What makes up the descending aorta?
Bronchoesophageal artery
Dorsal intercostal arteries
What does the costocervical trunk supply?
The first three dorsal intercostal spaces and muscles of the neck
What does the vertebral artery supply?
Supplies the brain
What does the superficial cervical artery supply?
Structures of the neck
What are the species differences of the azygous vein?
Dog and horse: right only
Pig: left only
Ruminants: right and left
