Diaphragm and Respiratory Movements Flashcards
What is the diaphragm?
Sheet of skeletal muscle forming the boundary between the thoracic and abdominal cavities.
What type of muscle is the diaphragm composed of?
Skeletal muscle.
What classifies the diaphragm anatomically?
4 attachments
3 major hiatuses and a number of minor ones
What do hiatuses in the diaphragm allow?
Permit structures to pass between the thorax and the abdomen.
What is the diaphragm the main muscle of?
Respiration.
What is the main muscle of respiration?
Diaphragm.
What does the diaphragm assist in raising intra-abdominal pressure in?
Coughing
Vomiting
Defaecation
What does the diaphragm do in coughing, vomiting and defaecation?
Raising intra-abdominal pressure.
What can be identified on the diaphragm?
Central tendon
Left and right crus/crura
Hiatuses for the IVC, oesophagus and aorta
What are hiatuses?
Openings.
What openings exist in the diaphragm?
Hiatuses for the IVC, oesophagus and aorta.
Are there more diaphragms in the body?
Yes- any sheet of skeletal muscle stretching from the midline of the body is termed a diaphragm.
Why does the right diaphragmatic dome lie more superior during normal expiration?
Presence of the liver.
What is the cardiac structure attached to the central tendon?
Fibrous pericardium.
What part of the diaphragm is the fibrous pericardium attached to?
Central tendon.
What is the left crura attached to?
Upper three vertebrae.
What is the right crura attached to?
Corresponding parts of the upper two vertebrae only.
What crura is attached to the upper three vertebrae?
Left crus.
What crura is attached to the upper two vertebrae only?
Right crus.
What is the membrane covering the superior surface of the diaphragm called?
Diaphragmatic pleura.
What happens to the diaphragm on inhalation?
Contracts and flattens out so the chest cavity can enlarge.
What shape is the central tendon?
Trefoil clover.
What attachments does the diaphragm have?
Once central tendinous and 3 peripheral. bony attachments.
What is the tendon attached to the diaphragm?
Central tendon.
What are the costal cartilages attached to the diaphragm?
Ribs 7-10.
What part of the sternum is the diaphragm attached to?
Xiphoid process.
What vertebrae are the diaphragm attached to?
Lumbar vertebrae.
Where is the hiatus for the inferior vena cave?
Vertebral level T8.
Where is the hiatus for the oesophagus?
Vertebral level T10.
Where is the hiatus opening for the aorta?
Vertebral level T12.
Where does the inferior vena cava pass through the diaphragm?
Passes through the vena caval foramen- a quadrilateral opening of tendinous origin.
What does the circulatory function of the diaphragm produce?
Oscillatory composition of IVC blood.
During inspiration, what IVC composition is favoured?
Splanchnic venous return.
During expiration, which IVC composition is favoured?
Venous return of blood below the entry of the hepatic vein.
Why will a structure passing through the diaphragm anteriorly pass through it at a more superior vertebral level?
Dome-like shape.
Name some additional structures that also traverse the diaphragm.
Azygous vein Thoracic duct Sympathetic trunks Phrenic nerves Vagus nerves
What is a hiatal hernia?
Abdominal profusion of a structure into the thorax through a tear or weakness in the diaphragm.
Where does the diaphragm receive innervation?
Receives motor and sensory supply on both its left and right sides and its superior and inferior surfaces.
What are the most important nerves supplying the diaphragm?
Paired phrenic nerves (both motor and sensory to the diaphragm)
Lower intercostal nerves provide sensory supply to peripheral regions.
What supplies both motor and sensory innervation to the diaphragm?
Paired phrenic nerves.
What supplies sensory innervation to peripheral diaphragmatic regions?
Lower intercostal nerves.
Hoe do the paired phrenic nerves supply the diaphragm?
Both motor and sensory supply.
How do the lower intercostal nerves supply the diaphragm?
Provide sensory supply to peripheral regions.
What vertebral levels of the spinal cord contribute to the phrenic nerves?
C3-C5.
What will result in quadriplegia?
Spinal cord injury below the phrenic nerve spinal levels.
What will spinal cord injury above the phrenic nerve spinal nerves result in?
Paralysis of the diaphragm and need for artificial ventilation.
What movements does normal inspiration involve?
Contraction of respiratory muscles to increase the volume capacity of the chest cavity.
Is normal expiration active or passive?
Passive.
What does forced inspiration involve?
Accessory muscles.
What type of inspiration requires the use of accessory muscles.
Forced inspiration.
Does normal inspiration require the use of accessory muscles?
No.
What are accessory muscles usually attached to?
Usually attached to the superior and inferior boundaries of the thoracic cavity (eg. muscles of the neck attaching to the sternum and upper ribs, muscles of the abdomen attaching to the lower ribs).
What can be attached to the superior and inferior boundaries of the thoracic cavity to aid respiratory movements?
Accessory muscles.
What can result in paralysis of the ipsilateral diaphragmatic dome?
Damage to the phrenic nerve.
What penetrating wounds should be suspected of causing damage to the diaphragm?
Below the nipples (4th intercostal space), owing to upwards arching of the domes in quiet expiration to the fifth rib or higher.
