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
What is the medial wall of the pleural cavity
The medial wall of each pleural cavity is the mediastinum
Fig. 3.35
Label and caption the image
- Right lung
- Mediastinum
- Rib I
- Left lung
- Rib VIII
- Rib X
- Diaphragm
- Parietal pleura
- Visceral pleura
- Pleural cavity
Pleural cavities
What is each pleural cavity lined by?
A single layer of flat cells, mesothelium, and an associated layer of supporting connective tissue; together, they form the pleura.
What are the two major types of pleura?
Based on location:
PARIETAL PLEURA
VISCERAL PLEURA
What is parietal pleura associated with/
The walls of a pleural cavity (Fig. 3.35)
What is the visceral pleura associated with?
It reflects from the medial wall and onto the surface of the lung, which adheres to and covers the lung (Fig. 3.35)
What is the pleural cavity?
The potential space enclosed between the visceral and parietal pleurae.
What does the pleural cavity contain?
Only a very thin layer of serous fluid.
What is the function of the pleural cavity?
The surface of the lung, which is covered by visceral pleura, directly opposes and freely slides over the parietal pleura attached to the wall (due to the very thin layer of serous fluid in the cavity).
What are the name given to the parietal pleura?
They correspond to the parts of the wall with which they are associated (Fig. 3.36):
- COSTAL PART
- DIAPHRAGMATIC PART
- MEDIASTINAL PART
- CERVICAL PLEURA
What is the costal part of the parietal pleura?
Pleura related to the ribs and intercostal spaces
What is the diaphragmatic part of the parietal pleura?
Pleura covering the diaphragm
What is the mediastinal part of the parietal pleura?
Pleura covering the mediastinum
What is the cervical pleura of the parietal pleura?
The dome-shaped layer of parietal pleura lining the cervical extension of the pleural cavity
What can cervical pleura also be known as?
CERVICAL PLEURA = DOME OF PLEURA or PLEURAL CUPOLA
Fig. 3.36
Label and caption the image.
- Suprapleural membrane
- Cervical pleura
- Pleura surrounding structures in root of lung
- Pulmonary ligament
- Costal part
- mediastinal part
- Diaphragmatic part
Parietal pleura
What covers the superior surface of the cervical pleura?
A distinct dome-like layer of fascia, the SUPRAPLEURAL MEMBRANE (Fig. 3.36)
What is the suprapleural membrane?
A distinct dome-like layer of ascia covering the superior surface of the cervical pleura.
What is the suprapleural membrane attached to?
This connective tissue membrane is attached laterally to the medial margin of the first rib and behind to the transverse process of vertebra CVII.
Superiorly, the suprapleural membrane receives muscle fibres from ___?
Some of the deep muscles in the neck (scalene muscles)
What function do scalene muscles have on the suprapleural membrane?
They keep the membrane taut.
What does the suprapleural membrane do?
Provides apical support for the pleural cavity in the root of the neck.
What happens to the mediastinal pleura in the region of vertebrae TV to TVII?
It reflects of the mediastinum as a tubular, sleeve-like covering for structures (i.e., airway, vesssels, nerves, lymphatics) that pass between the lung and mediastinum.
The sleeve-like covering of the mediastinal pleura, and the structures it contains, forms ___?
The ROOT OF THE LUNG.
The root of the lung joins the medial surface of the lung at an area referred to as ___
the HILUM OF THE LUNG.
The hilum of the lung is where the ____ pleura is continuous with the ____ pleura.
mediastinal and visceral pleura
What is the parietal pleura innervated by?
Somatic afferent fibres.
What is the costal pleura innervated by?
Branches from the intercostal nerves
How is pain of the costal pleura felt?
In relation to the thoracic wall
What are the diaphragmatic pleura and the mediastinal pleura innervated by?
Mainly by the phrenic nerves (originating at spinal cord levels C3, C4 and C5).
Where would you feel pain from the diaphragmatic and mediastinal pleura?
Pain from these areas would refer to the C3, C4 and C5 dermatomes (lateral neck and the supraclavicular region of the shoulder).
What marks the extent of the pleural cavities?
The peripheral reflections of parietal pleura (Fig. 3.37)
Fig. 3.37
Label and caption the image
- MIDCLAVICULAR LINE
- MIDAXILLARY LINE
- Vertebra TXII (posterior)
- Rib X (lateral)
- Rib VIII (anterior)
Pleural reflections.
Superiorly, the pleural cavity can project as much as _____ above the ____ ____ ____ but does not extend above the ____ of ___ _.
3-4 cm, above the first costal cartilage, but does not extend above the neck of rib I.
Why does the pleural cavity not extend above the neck of rib I?
This limitation is caused by the inferior slope of rib I to its articulation with the manubrium.
Anteriorly, how do the pleural cavities approach each other?
Posterior to the upper part of the sternum.
Why does the parietal pleura not reach as close to the midline on the left side of the heart?
Posterior to the lower part of the sternum, the parietal pleura does not come as close to the midline on the left side as it does on the right because the middle mediastinum, containing the pericardium and heart, bulges to the left.
Inferiorly, where does the costal pleura reflect?
Onto the diaphragm above the costal margin.
In the midclavicular line, where does the pleural cavity extend?
Inferiorly to approximately rib VIII.
In the midaxillary line, where does the pleural cavity extend?
Rib X
What happens to the inferior margin of the pleural cavity from the midaxillary line onwards?
The inferior margin courses somewhat horizontally, crossing ribs XI and XII to reach vertebra TXII.
Where is the inferior boundary of the pleura?
From the midclavicular line to the vertebral column, this can be approximated by a line that runs between rib VIII, rib X and vertebra TXII.
Where is the visceral pleura continuous with the parietal pleura?
At the hilum of each lung
What is the hilum of the lung?
Where structures enter and leave the organ.
What is the visceral pleura attached to?
It is firmly attached to the surface of the lung, including both opposed surfaces of the fissures that divide the lungs into lobes.
What is the visceral pleura innervated by?
Visceral aferent nerves that accompany bronchial vessels
Describe a fact about the visceral pleura sensory innervation.
Pain is generally not elicited from this tissue.
The lungs do not _______ ___ the _____ or ____ _____ regions of the pleural cavities.
completely fill; anterior or posterior (Fig. 3.38)
The lungs do not completely fill the pleural cavity. This results in _____ in which two layers of ____ pleura become opposed.
Recesses in which two layers of parietal pleura become opposed.
Expansion of the lungs into the pleural recesses usually occurs ___?
Only during forced inspiration
What is clinically significant about the pleural recesses?
They provide potential spaces in which fluids can collect and from which fluids can be aspirated.
Fig. 3.38
Label and caption the image
- MIDCLAVICULAR LINE
- MIDAXILLARY LINE
- Vertebra TX (posterior)
- Rib VIII (lateral)
- Costodiaphragmatic recess
- Rib VI (anterior)
- Costomediastinal recess
Parietal pleural reflections and recesses
Where is the costomediastinal recess?
Anteriorly, this occurs on each side where costal pleura is opposed to mediastinal pleura.
Where is the largest costomediastinal recess?
On the left side in the region overlying the heart (Fig. 3.38)
What are the largest and clinically most important recesses?
The COSTODIAPHRAGMATIC RECESSES
Where do the costodiaphragmatic recesses occur?
In each pleural cavity between the costal pleura and diaphragmatic pleura (Fig. 3.38)
What are the costodiaphragmatic recesses?
The regions between the inferior margin of the lungs and inferior margin of the pleural cavities.
When are the costodiaphragmatic recesses deepest?
After forced expiration
When are the costodiaphragmatic recesses shallowest?
After forced inspiration
What happens to the inferior margin of the lung during quiet respiration?
It crosses rib VI in the midclavicular line and rib VIII in the midaxillary line, and then courses somewhat horizontally to reach the vertebral column at vertebral level TX.
Where can the inferior margin of the lung be approximated?
From the midclavicular line and around the thoracic wall to the vertebral column, it can be approximated by a line running between rib VI, rib VIII and vertebra TX.
The inferior margin of the ____ from the midclavicular line to the vertebral column is rib VIII, rib X and vertebra TXII.
Pleural cavity
Where does the costodiaphragmatic recess lie?
Between the inferior margin of the lung and pleural cavity.
During expiration, the inferior margin of the lung _____ and the costodiaphragmatic recess becomes ______.
Rises, larger
(IN THE CLINIC: Pleural effusion)
What is a pleural effusion?
When excess fluid accumulates within the pleural space
(IN THE CLINIC: Pleural effusion)
What occurs when fluid accumulates within the pleural space?
The underlying lung is compromised and may collapse as the volume of fluid increases.
(IN THE CLINIC: Pleural effusion)
What is the treatment once a pleural effusion has been diagnosed?
Fluid often will be aspirated to determine the cause
(IN THE CLINIC: Pleural effusion)
What are the causes of pleural efusion?
Causes can include:
- infection
- malignancy
- cardiac failure
- hepatic disease
- pulmonary embolism
(IN THE CLINIC: Pneumothorax)
What is a pneumothorax?
A collection of gas or air within the pleural cavity
(IN THE CLINIC: Pneumothorax)
What occurs in a pneumothorax?
When air enters the pleural cavity the tissue elasticity of the parenchyma causes the lung to collapse within the chest, impairing the lung function.
(IN THE CLINIC: Pneumothorax)
What may occur to the mediastinum in a pneumothorax?
Occasionally, the gas within the pleural cavity may accumulate to such an extent that the mediastinum is “pushed” to the opposite side, compromising the other lung.
(IN THE CLINIC: Pneumothorax)
What is a tension pneumothorax?
When gas within the pleural cavity accumulates to such an extent that the mediastinum is “pushed” to the other side
(IN THE CLINIC: Pneumothorax)
What type of pneumothorax requires urgent treatment?
A tension pneumothorax
(IN THE CLINIC: Pneumothorax)
What causes most pneumothoraces?
Most are spontaneous (i.e., they occur in the absence of no known pathology and no known lung disease).
(IN THE CLINIC: Pneumothorax)
What are some possible causes of pneumothoraces?
Most are spontaneous, but they may occur also as a result of:
- trauma
- inflammation
- smoking
- other underlying pulmonary diseases
(IN THE CLINIC: Pneumothorax)
What are the severity of symptoms of pneumothorax?
These are often determined by the degree of air leak and the rate at which the accumulation of gas occurs and the ensuing lung collapses.
(IN THE CLINIC: Pneumothorax)
What are the symptoms of pneumothorax?
They include:
- pain
- shortness of breath
- cardiorespiratory collapse, if severe
