Thorax Flashcards
What are the cranial and caudal borders of the thorax?
thoracic inlet (cranial) diaphragm (caudal)
What is a serous membrane made of?
mesothelium (simple squamous) with basement membrane & underlying connective tissue
What is the function of serous membranes?
to secrete small volumes of serous fluid for lubrication between organs & body wall
True/False Serous membranes contain organs
False only small amount of serous fluids, otherwise empty
Characteristics of serous membranes
continuous thin translucent
Name the serous membranes throughout the body
pleura (thoracic) (2 of them)
pericardium (around the heart)
peritoneum (abdomen)
List the regional names of the pleura.
parietal membrane
visceral membrane
What is the mediastinum?
the space between the pleural membranes
Draw & label a schematic of the pleural cavities. (transverse)
List the main arteries branching from the aorta.
Which arteries supply the heart?
L&R coronary arteries
List the arteries in the brachiocephalic trunk & what they supply.
L&R caroted arteries - supply the head
R subclavian artery - supplies forelimb, neck, cervicothoracic region
What are the intercostal arteries?
9 paired (L&R) branches of blood vessels between the ribs
branch off the aorta
supply intercostal muscles
Explain the progression of the subclavian artery.
L originates at the aorta
R originates at the brachiocephalic trunk
each has 4 branches
after branches runs into the axillary arteries
axillary arteries supply the forelimbs
List the main veins of the thorax & where they come from.
cranial vena cava - head, neck, forelimbs
caudal vena cava - abdominal, pelvic, hindlimbs
azygous vein - intercostal spaces & lumbar
What tributaries form the cranial vena cava? In order from cranial to caudal
external & internal jugular veins
subclavian veins
brachiocephalic veins
cranial vena cava
How would you view the azygous vein most easily?
R side of mediastinum
dorsal to descending thoracic aorta
drains into cranial vena cava OR R atrium directly
True/False
The azygous vein is paired
False
only one, only R side
Which vein has a fold of mediastinal pleura?
caudal vena cava
Draw & label a schematic of the main thoracic veins.
Draw & label a schematic of the main thoracic arteries.
List the lobes of the lungs.
L: cranial (has cranial & caudal parts) & caudal lobes
R: cranial, middle, diphragmatic, accessory lobes
What is the cardiac notch?
Why is it clinically significant?
where the heart is not overlain with lung tissue
best place to listen to the heart
What is the diaphragm?
skeletal muscle with tendonous centre
cranially-domed air tight partition between thorax & abdomen
covered in parietal pleural & parietal peritoneum
List attachment sites of the diaphragm.
sternal - dorsal surface of sternum cranially to xyphoid
costal - medial surface of ribs 8-13
lumbar - L&R crura at ventral region of 3&4th lumbar vertebrae
What innervates the diaphragm?
L& R phrenic nerves (come from cervical spinal nerves 5-7)
List the foramina of the diaphragm & what passes through them.
aortic hiatus - aorta, azygous vein, thoracic duct, sympathetic trunk
oesophageal hiatus - oesophagus, dorsal & ventral vagal nerves
caval foramen - caudal vena cava
Which muscles are involved in inspiraton?
diaphragm
scalenus
serratus dorsalis cranialis
external intercostal muscles
internal intercostal muscles (ventral interchondral)
Explain the process of inspiration.
ribs move down, out, forewards - increases transverse diameter of thoracic cavity
diaphragm flattens - increases longitudinal diameter
serratus dorsalis cranialis controls rib lifting
increasing diameter causes increased volume, lungs expand, negative pressure draws air in
Explain the processes of passive & active exhalation.
Passive: elastic recoil of lungs d/t elastic costovertebral ligmanets & durface tension in air passages
Active: internal intercostal muscles, serratus dorsalis caudalis, abdominal muscles (contract to re-dome diaphragm) - reduces negative pressure
Describe arrangement of pleura surrounding pleural cavity.
What is the costo-diaphragmatic recess?
What is the clinical significance?
.
Draw & label a schematic of the pleural membranes (dorsal).
What is the costodiaphragmatic recess?
region between line of pleural reflection & caudal border of lungs
lungs can expand here in disease or heavy exercise but not normally
Draw & label a schematic of the pericardium.
List the components of the parietal pericardium.
inner, smooth, serous
outer fibrous - continues to phrenicopericardial ligament & secures to diaphragm
Draw & label a schematic of the thorax including major nerves & organs. (leave lungs out)
