Canine Thorax Flashcards
What are the ventral body cavities? What are they divided by?
thoracic and abdominopelvic cavities. Divided by the diaphragm
What are the 3 main characteristics of body cavities?
- they are bound by muscle and bone
- are lined by serous membranes
- contain viscera
What are the skeletal boundaries of the thoracic cavity?
Dorsally: thoracic vertebrae Laterally: ribs and costal cartilages Ventrally: sternebrae and costal cartilages Cranially: thoracic inlet Caudally: diaphragm
What are the muscles of the thoracic wall primarily utilized for?
respiration
What are the muscles of the thoracic wall?
Serratus dorsalis cranialis and caudalis, external and internal intercostals, retractor costae, scalenus, rectus abdominis, transversus thoracis (intrathoracic)
What are the parts of the diaphragm?
- Muscular (R/L costal parts, sternal part, lumbar part with R/L crura)
- Tendinous (central tendon, R/L crural tendons
What are the attachments/coverings of the diaphragm?
- Pleural covering
- Diaphragmatic line of pleural reflection
- Mediastinal attachment
- Plica venae cavae
What are the openings in the diaphragm?
- Lumbocostal arch
- Aortic hiatus
- Esophageal hiatus
- Caval foramen
How does the diaphragm attach to the bodies of the third and fourth lumbar vertebrae?
tendinous crural attachments
What happens when the diaphragm contracts?
it flattens -> moves the caudal boundary of the thoracic cavity caudally.
What is the tunica serosa?
serous membrane that lines and encloses body cavities, known as serous cavities.
What is the tunica serosa composed of?
a secretory epithelial layer (mesothelium) and an underlying connective tissue layer (eg: endothoracic fascia)
What does the tunica serosa do?
secretes serous fluid to reduce friction as organs are moved against one another and the cavity walls
How are tunica serosa named?
according to their location (parietal or visceral) and the cavity that they define (pleural, pericardial, peritoneal)
What lines the walls of a cavity?
parietal serous membranes
What covers the surface of an organ?
visceral serous membranes
What layers of a serous membrane are continuous?
parietal and visceral layers
What are the three serous cavities within the thoracic cavity?
- left pleural cavity
- right pleural cavity
- pericardial cavity
Where does the pericardial cavity develop? what is this?
mediastinum - the space between two pleural cavities;continuous with the cervical visceral space
What are some specific regions of the parietal pleura of the thoracic cavity?
- costal pleura
- sternal pleura
- diaphragmatic pleura
- mediastinal pleura
- diaphragmatic line of pleural reflection
What is a specific visceral pleura of the thoracic cavity?
pulmonary pleura
What is located between the left and right pleural cavities?
the pericardial cavity which develops within the mediastinal space
Where/how to recesses (pockets) occurr in a pleura?
where the pleura reflects from one cavity wall to another
What are the pleural recesses in the thoracic cavity?
- pleural cupula (protrudes from thoracic inlet)
- costodiaphragmatic
- Costomediastinal
- Mediastinal recess (contains accessory lobe of right lung)
What does the mediastinum extend between?
the thoracic inlet to the diaphragm
What are the subdivisions of the mediastinum?
cranial mediastinum, middle mediastinum, caudal mediastinum
What is the mediastinal space continued cranially through the thoracic inlet by?
the visceral space of the neck (cervical visceral space)
What muscles bind the cervical visceral space?
- sternocephalicus
- sternothyrohyoideus
- longus capitis
- longus coli
What does the cervical visceral space include/contain?
- trachea
- esophagus
- thyroid and parathyroid glands
- recurrent laryngeal nerves
- tracheal lymph nodes
- carotid sheath
What does the carotid sheath contain?
- common carotid artery
- vagosympathetic trunks
- internal jugular veins
What is contained within the mediastinum?
Thymus, trachea, esophagus, phrenic nerves (R/L), vagus nerves (R/L), vagal trunks (R/L), paravertebral (sympathetic) chain of ganglia (R/L), heart (in pericardium), aorta, pulmonary trunk. right azygos vein (right only in dog and horse, R/L in ox), thoracic duct, tracheobronchial lymph nodes
True or false? the lungs are contained within the mediastinum?
false
What are the two portions of the respiratory system?
the exchange portion and conducting portion
what does the conducting portion of the respiratory system contain?
trachea, bronchial tree
What are the parts of the bronchial tree?
- R/L principle bronchi
- carina
- lobar bronchi
- segmental bronchi
- branches of segmental bronchi
- bronchioles
Where does the exchange portion of the respiratory system begin?
at the respiratory bronchioles
What are the parts of the exchange portion?
- respiratory bronchioles (w/ alveoli)
- alveolar ductules
- alveolar saccules
What is the trachea comprised of?
incomplete cartilaginous rings that are connected by tracheal (annular) ligaments
True or false? the veins accompanying the bronchial tree are located dorsal to the arteries
false - they are located ventral to the arteries
What is the functional blood supply to the lungs?
pulmonary arteries and veins
What is the nutritive blood supply to the lungs?
bronchoesophageal artery and azygous vein
What are the lobes of the left lung?
cranial lobe (divided into cranial and caudal parts) and the caudal lobe
What are the lobes of the right lung?
Cranial lobe, middle lobe, caudal lobe, accessory lobe
What is located between the basal border of the lung and the diaphragmatic line of pleural reflection?
the costodiaphragmatic recess
Which lung has the cardiac notch?
right lung
What are the lymph nodes of the lungs?
- R/L tracheobronchial ln
- middle tracheobronchial ln
- pulmonary ln
What are the two major distinguishable branches before the descending aorta?
brachiocephalic trunk and Left subclavian artery
What are the branches of the left and right subclavian arteries?
- costocervical trunk
- vertebral a.
- superficial a.
- internal thoracic a.
What does the costocervical trunk supply?
cranial intercostal spaces and muscles of the neck
What does the vertebral artery supply and extend through?
extends through transverse vertebral foramina; supplies the brain
What does the superficial cervical artery supply?
the superficial structures of the neck
What does the internal thoracic artery supply?
- ventral intercostal aa. (intercostal spaces)
- Musculophrenic (diaphragm)
- cranial epigastric a. (continues as?
What are the veins of the thorax?
- right azygous vein
- caudal/cranial vena cava
- other veins distribute with their arterial counterparts
What are the pulmonary ligaments?
double layers of serous membrane that extend from the mediastinal (parietal) pleura to the visceral pleura
What is the plica vena cava?
a fold of serous membrane (from mediastinal pleura) that envelops the caudal vena cava and right phrenic nerve
