Session 1.2e - Gray's Anatomy for Students - Thorax - Regional anatomy - Diaphragm etc. Flashcards
- Diaphragm - Movements of the thoracic wall and diaphragm during breathing - Pleural cavities https://www.clinicalkey.com/#!/content/book/3-s2.0-B9780702051319000031?scrollTo=%23hl0001925
What is the diaphragm?
A thin musculotendinous structure that fills the inferior thoracic aperture and separates the thoracic cavity from the abdominal cavity (Fig. 3.33).
What is the diaphragm attached peripherally to?
- xiphoid process of the sternum
- costal margin of the thoracic wall
- ends of ribs XI and XII
- ligaments that that span across structures of the posterior abdominal wall
- vertebrae of the lumbar region
Fig. 3.33
Label and caption the image.
- Right phrenic nerve
- Right pericardiacophrenic artery
- Right vagus nerve
- Esophagus
- Inferior vena cava
- Central tendon of diaphragm
- Phrenic nerves
- Inferior phrenic arteries
- Left phrenic nerve
- Left pericardiacophrenic artery
- Left vagus nerve
- Internal thoracic arteries
- Esophageal hiatus
- Aortic hiatus
- Superior epigastric artery
- Musculophrenic artery
- Right crus
- Abdominal aorta
Diaphragm
How do the muscle fibres of the diaphragm join?
From these peripheral attachments, muscle fibres converge to join the central tendon.
How is the pericardium attached to the diaphragm?
To the middle part of the central tendon.
What occurs to the diaphragm in the median sagittal plane?
It slopes inferiorly from its anterior attachment to the xiphoid, approximately at vertebral level TVIII/IX, to its posterior attachments to the MEDIAN ARCUATE LIGAMENT, crossing anterior to the aorta at approximately vertebra level TXII.
Structures travelling between the thorax and abdomen pass ___
Through the diaphragm or between the diaphragm and its peripheral attachments.
What structures pass through the diaphragm?
- Inferior vena cava
- Oesophagus
- Vagus nerves
- Aorta
- Thoracic duct
- Azygos and hemiazygos veins
Where does the inferior vena cava pass through the diaphragm?
Through the central tendon at approximately vertebral level TVIII.
Where does the oesophagus pass through the diaphragm?
Through the muscular part of the diaphragm, just to the left of midline, approximately at vertebral level TX.
Where do the vagus nerves pass through the diaphragm?
With the oesophagus
Where does the aorta pass through the diaphragm?
Passes behind the posterior attachment of the diaphragm at vertebral level TXII.
Where does the thoracic duct pass through the diaphragm?
Behind the diaphragm with the aorta
Where do the azygos and hemiazygos veins pass through the diaphragm?
Through the aortic hiatus or through the crura of the diaphragm
Other structures outside the posterior attachments of the diaphragm lateral to the aortic hiatus include ___
the sympathetic trunks.
Which nerves penetrate the crura?
Greater, lesser, and least splanchnic nerves.
The arterial supply to the diaphragm is from vessels that arise _____ and ____ to it.
Superiorly and inferiorly (Fig. 3.33)
From above, ___ and ___ arteries supply the diaphragm.
Pericardiacophrenic and musculophrenic
The pericardiacophrenic and musculophrenic are branches of ___?
The internal thoracic arteries.
Which arteries arise directly from lower parts of the thoracic aorta?
SUPERIOR PHRENIC ARTERIES and small branches from intercostal arteries contribute to the diaphragmatic supply.
What are the largest arteries supplying the diaphragm?
INFERIOR PHRENIC ARTERIES
Where do the inferior phrenic arteries arise from?
Below the diaphragm
Where do the inferior phrenic arteries branch?
Directly from the abdominal aorta.
What is the venous drainage of the diaphragm?
By veins that generally parallel the arteries.
Where do the veins drain into?
- the brachiocephalic veins in the neck,
- the AZYGOS SYSTEM OF VEINS, or
- abdominal viens (left suprarenal vein and inferior vena cava)
What is the diaphragm innervated by?
The PHRENIC NERVES (C3, C4 and C5)
How is the phrenic nerve associated with the diaphragm?
It penetrates it and innervates it from its abdominal surface.
How is thoracic volume increased via the diaphragm?
Contraction of the domes of the diaphragm flattens the diaphragm.
What are movements of the diaphragm essential for?
Normal breathing
What is one of the principal functions of the thoracic wall and the diaphragm?
To alter the volume of the thorax and thereby move air in and out of the lungs.
What happens to the thorax during breathing?
The dimensions change in the vertical, lateral and anteroposterior directions.
How does the diaphragm significantly alter vertical dimensions of the thorax?
Via elevation and depression
How does depression of the diaphragm occur?
Results when the muscles fibres of the diaphragm contract.
How does elevation of the diaphragm occur?
When the diaphragm relaxes
Elevation and depression of the ribs causes ___?
Changes in the anteroposterior and lateral dimensions of the ribs (Fig. 3.34).
What do the ribs articulate with?
The posterior ends with the vertebral column
The anterior ends of most ribs articulate with the sternum or adjacent ribs
Fig. 3.34
Label and caption the image.
A - Superior and anterior movement of sternum
- Pump handle
B - Bucket handle movement
- Elevation of lateral shaft of rib
Movement of thoracic wall during breathing. A. Pump handle movement of ribs and sternum. B. Bucket handle movement of ribs.
The _____ ends of the ribs are inferior to the _____ ends.
Anterior, posterior
When the ribs are elevated, they move the sternum ____.
upward and forward
As well as moving the sternum, what else occurs to the sternum when the ribs are elevated?
The angle between the body of the sternum and the manubrium may become slightly less acute.
The sternum moves downward and backward when ___?
The ribs are depressed
How do the ribs change the dimensions of the thorax?
They use a “pump handle” movement to change the dimensions of the thorax in the anteroposterior direction (Fig. 3.34A)
As well as the anterior ends of the ribs being lower than the posterior ends, the ______ __ __ ______ tend to be lower than the two ends.
Middles of the shafts
When the shafts are elevated, the _______ of the shafts move _______.
Middles, laterally
How does the shaft of the rib change the dimensions of the thorax?
This “bucket handle” movement increases the lateral dimensions of the thorax (Fig. 3.34B).
What muscles act as accessory respiratory muscles?
Any muscles attaching to the ribs, as these can potentially move one rib relative to another
What muscles can fix or alter the positions of upper and lower ribs?
Muscles in the neck and the abdomen can fix or alter the positions of upper and lower ribs.
What surrounds the lungs?
Two PLEURAL CAVITIES, one on either side of the mediastinum (Fig. 3.35).
Where do the pleural cavities extend superiorly?
Above rib I into the root of the neck
Where do the pleural cavities extend inferiorly?
To a level just above the costal margin