Dashboard Subscription expires in: <1 Day Extend
You have scored 13%
You answered 17 correct out of 134 questions.
Your answers are shown below:
Contraction of the diaphragm results in which of the following effects:
a) Elevation of the diaphragm
b) Increased vertical dimension of the thorax
c) Decreased intra-abdominal pressure
d) Increased anteroposterior dimension of the thorax
e) Increased intrathoracic pressure
Something wrong?
Answer
Contraction of the diaphragm (as in inspiration) results in attening (depression) of the diaphragm with an increase in
vertical dimension of the thorax. This results in decreased intrathoracic pressure and increased intra-abdominal
pressure.
Notes
The diaphragm is a musculotendinous structure that separates the thoracic cavity from the abdominal cavity.
Structure Diaphragm
Primary Respiration – contraction of diaphragm attens diaphragm increasing vertical dimension of thorax
function (inspiration), relaxation of diaphragm elevates diaphragm decreasing vertical dimension of thorax
(expiration)
, Secondary Assists in straining movements by increasing intra-abdominal pressure, acts as functional
functions sphincter on oesophagus preventing acid re ux
Peripheral Xiphoid process of sternum, costal cartilages ribs 7 – 10, ends of ribs 11 and 12, arcuate ligaments
attachments and lumbar vertebrae
Central Fuses with brous pericardium superiorly
attachment
Surface Attachments: vertebrae T8/T9 anteriorly, vertebra T12 posteriorly, Domes: right dome 5th rib,
markings left dome 5th intercostal space
Openings Oesophageal opening at T10 (oesophagus, vagus nerve), aortic opening at T12 (aorta, thoracic
duct and azygos vein), caval opening at T8 (inferior vena cava and right phrenic nerve)
Innervation Phrenic nerve (C3 – C5)
By OpenStax [CC BY 4.0 (http://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons
Function
The diaphragm performs an important function in respiration; contraction of the domes of the diaphragm in inspiration
attens the diaphragm, increasing the vertical dimension of the thorax and vice versa in expiration, with relaxation and
elevation of the diaphragm reducing the vertical dimension of the thorax.
The diaphragm is also involved in non-respiratory functions; helping to expel vomit, faeces, and urine from the body by
,The diaphragm is also involved in non-respiratory functions; helping to expel vomit, faeces, and urine from the body by
increasing intraabdominal pressure, and preventing acid re ux by exerting pressure on the oesophagus as it passes
through the oesophageal opening.
Attachments
The diaphragm is attached peripherally to:
the xiphoid process of the sternum and the costal cartilages of ribs 7 – 10 (the costal margin) anteriorly
the ends of ribs 11 and 12 laterally
the arcuate ligaments and vertebrae posteriorly.
From these peripheral attachments, muscle bres converge to form the central tendon which fuses with the brous
pericardium superiorly.
Surface markings
In the medial sagittal plane, the diaphragm slopes inferiorly from its anterior attachment to the xiphoid at
approximately vertebral level T8/T9 to its posterior attachment to the median arcuate ligament at approximately
vertebral level T12.
At rest the right dome of the diaphragm lies slightly higher than the left; this is thought to be due to the position of the
liver. In normal expiration, the normal upper limits of the superior margins are the fth rib for the right dome, the fth
intercostal space for the left dome and the xiphoid process for the central tendon.
Diaphragmatic openings
Structures travelling between the thorax and abdomen must pass through the diaphragm via three main openings.
The oesophageal opening at vertebral level T10 transmits:
the oesophagus
the anterior and posterior vagal trunks
oesophageal branches of the left gastric vessels
a few lymphatics.
The aortic opening at vertebral level T12 transmits:
the aorta
the thoracic duct
the azygos vein and sometimes the hemiazygos vein.
The caval opening at vertebral level T8 transmits:
the inferior vena cava
the right phrenic nerve.
Innervation
, Innervation
The entire motor supply of the diaphragm is from the right and left phrenic nerves (C3 – C5) which penetrate the
diaphragm and innervate it from its abdominal surface.
Damage to the phrenic nerve will result in hemiparalysis of the diaphragm. Paralysis of the diaphragm produces a
paradoxical movement. The affected side of the diaphragm moves upwards during inspiration (as it is pushed
superiorly by the abdominal viscera that are being actively compressed by the other half), and downwards during
expiration.
A unilateral diaphragmatic paralysis is usually asymptomatic, and is most often an incidental nding on x-ray. If both
sides are paralysed, the patient may experience poor exercise tolerance, orthopnoea and fatigue. Lung function tests
will show a restrictive de cit.
Diaphragmatic herniation
Diaphragmatic hernias are de ned as congenital or acquired defects in the diaphragm. There are two main types of
congenital diaphragmatic hernias; Bochdalek hernias and Morgagni hernias.
Acquired diaphragmatic hernias include traumatic diaphragmatic rupture, hiatus hernia and iatrogenic diaphragmatic
hernias. Depending on the location and size of the defect, retroperitoneal or intra-abdominal organs and tissues can
prolapse into the thoracic cavity due to the negative intrathoracic pressure.
Diaphragmatic rupture usually results from blunt abdominal trauma, which is typically associated with motor-vehicle
accidents; the most commonly herniated viscera are the stomach and colon on the left side, and the liver on the right
side.
In hiatus hernia, the stomach herniates through the oesophageal opening of the diaphragm, typically resulting in
symptoms of acid re ux.
The horizontal ssure of the lung separates which of the following:
a) Right superior and inferior lobes
b) Right superior and middle lobes
c) Left superior and inferior lobes
d) Left superior and middle lobes
e) Right middle and inferior lobes
Something wrong?
Answer
The horizontal ssure separates the right superior lobe from the right middle lobe.
Notes
You have scored 13%
You answered 17 correct out of 134 questions.
Your answers are shown below:
Contraction of the diaphragm results in which of the following effects:
a) Elevation of the diaphragm
b) Increased vertical dimension of the thorax
c) Decreased intra-abdominal pressure
d) Increased anteroposterior dimension of the thorax
e) Increased intrathoracic pressure
Something wrong?
Answer
Contraction of the diaphragm (as in inspiration) results in attening (depression) of the diaphragm with an increase in
vertical dimension of the thorax. This results in decreased intrathoracic pressure and increased intra-abdominal
pressure.
Notes
The diaphragm is a musculotendinous structure that separates the thoracic cavity from the abdominal cavity.
Structure Diaphragm
Primary Respiration – contraction of diaphragm attens diaphragm increasing vertical dimension of thorax
function (inspiration), relaxation of diaphragm elevates diaphragm decreasing vertical dimension of thorax
(expiration)
, Secondary Assists in straining movements by increasing intra-abdominal pressure, acts as functional
functions sphincter on oesophagus preventing acid re ux
Peripheral Xiphoid process of sternum, costal cartilages ribs 7 – 10, ends of ribs 11 and 12, arcuate ligaments
attachments and lumbar vertebrae
Central Fuses with brous pericardium superiorly
attachment
Surface Attachments: vertebrae T8/T9 anteriorly, vertebra T12 posteriorly, Domes: right dome 5th rib,
markings left dome 5th intercostal space
Openings Oesophageal opening at T10 (oesophagus, vagus nerve), aortic opening at T12 (aorta, thoracic
duct and azygos vein), caval opening at T8 (inferior vena cava and right phrenic nerve)
Innervation Phrenic nerve (C3 – C5)
By OpenStax [CC BY 4.0 (http://creativecommons.org/licenses/by/4.0)], via Wikimedia Commons
Function
The diaphragm performs an important function in respiration; contraction of the domes of the diaphragm in inspiration
attens the diaphragm, increasing the vertical dimension of the thorax and vice versa in expiration, with relaxation and
elevation of the diaphragm reducing the vertical dimension of the thorax.
The diaphragm is also involved in non-respiratory functions; helping to expel vomit, faeces, and urine from the body by
,The diaphragm is also involved in non-respiratory functions; helping to expel vomit, faeces, and urine from the body by
increasing intraabdominal pressure, and preventing acid re ux by exerting pressure on the oesophagus as it passes
through the oesophageal opening.
Attachments
The diaphragm is attached peripherally to:
the xiphoid process of the sternum and the costal cartilages of ribs 7 – 10 (the costal margin) anteriorly
the ends of ribs 11 and 12 laterally
the arcuate ligaments and vertebrae posteriorly.
From these peripheral attachments, muscle bres converge to form the central tendon which fuses with the brous
pericardium superiorly.
Surface markings
In the medial sagittal plane, the diaphragm slopes inferiorly from its anterior attachment to the xiphoid at
approximately vertebral level T8/T9 to its posterior attachment to the median arcuate ligament at approximately
vertebral level T12.
At rest the right dome of the diaphragm lies slightly higher than the left; this is thought to be due to the position of the
liver. In normal expiration, the normal upper limits of the superior margins are the fth rib for the right dome, the fth
intercostal space for the left dome and the xiphoid process for the central tendon.
Diaphragmatic openings
Structures travelling between the thorax and abdomen must pass through the diaphragm via three main openings.
The oesophageal opening at vertebral level T10 transmits:
the oesophagus
the anterior and posterior vagal trunks
oesophageal branches of the left gastric vessels
a few lymphatics.
The aortic opening at vertebral level T12 transmits:
the aorta
the thoracic duct
the azygos vein and sometimes the hemiazygos vein.
The caval opening at vertebral level T8 transmits:
the inferior vena cava
the right phrenic nerve.
Innervation
, Innervation
The entire motor supply of the diaphragm is from the right and left phrenic nerves (C3 – C5) which penetrate the
diaphragm and innervate it from its abdominal surface.
Damage to the phrenic nerve will result in hemiparalysis of the diaphragm. Paralysis of the diaphragm produces a
paradoxical movement. The affected side of the diaphragm moves upwards during inspiration (as it is pushed
superiorly by the abdominal viscera that are being actively compressed by the other half), and downwards during
expiration.
A unilateral diaphragmatic paralysis is usually asymptomatic, and is most often an incidental nding on x-ray. If both
sides are paralysed, the patient may experience poor exercise tolerance, orthopnoea and fatigue. Lung function tests
will show a restrictive de cit.
Diaphragmatic herniation
Diaphragmatic hernias are de ned as congenital or acquired defects in the diaphragm. There are two main types of
congenital diaphragmatic hernias; Bochdalek hernias and Morgagni hernias.
Acquired diaphragmatic hernias include traumatic diaphragmatic rupture, hiatus hernia and iatrogenic diaphragmatic
hernias. Depending on the location and size of the defect, retroperitoneal or intra-abdominal organs and tissues can
prolapse into the thoracic cavity due to the negative intrathoracic pressure.
Diaphragmatic rupture usually results from blunt abdominal trauma, which is typically associated with motor-vehicle
accidents; the most commonly herniated viscera are the stomach and colon on the left side, and the liver on the right
side.
In hiatus hernia, the stomach herniates through the oesophageal opening of the diaphragm, typically resulting in
symptoms of acid re ux.
The horizontal ssure of the lung separates which of the following:
a) Right superior and inferior lobes
b) Right superior and middle lobes
c) Left superior and inferior lobes
d) Left superior and middle lobes
e) Right middle and inferior lobes
Something wrong?
Answer
The horizontal ssure separates the right superior lobe from the right middle lobe.
Notes
