Lecture 14: Diaphragm Flashcards
What is the insertion of the diaphragm?
Converge into central tendon
What is the origin of the diaphragm?
Thoracic outlet, xiphoid process, costal cartilages of ribs 6-12, L1-L3 vertebrae
What is the motor Innervation to the diaphragm?
Right and left phrenic nerve (C3-C5 keeps the diaphragm alive)
What is the sensory Innervation to the diaphragm?
Phrenic nerve = central Intercostal nerve (T5-T11) = periphery
Which dome is higher?
Right
Purpose of crus in diaphragm?
Anchor diaphragm to lumbar vertebrae.
What is the right crus and where does it arise from?
larger & longer, arises from sides of L1-L3 vertebral bodies and IV discs.
What is the left crus and where does it arise from?
arises from sides of L1-L2 and IV disc.
What does the Median arcuate ligament connect?
left and right crura
Medial arcuate ligament covers what muscle?
thickening of fascia covering psoas major muscle
Lateral arcuate ligament covers what?
thickening of fasica covering quadratus lumborum muscle.
Caval opening at what level and what goes through it?
T8: Inferior vena cava and right phrenic nerve
Oesophageal hiatus at what level and what goes through it?
@T10: oesophagus, right and left vagus nerves.
Aortic hiatus at what level and what goes through it?
@T12: aorta, thoracic duct, azygos vein.
Structures passing around the diaphragm
Greater and lesser splanchnic nerves (pass through crura on each side). • Hemiazygos vein (passes through left crus). • Least splanchnic nerves and sympathetic trunks (pass posterior to medial arcuate ligament). • Superior epigastric vessels (anterior to diaphragm, just deep to ribs).
What is a Hiatal hernia?
Protrusion of the stomach into the thoracic cavity through a widening of the right crus of the diaphragm.
During expiration the right and left dome reach what levels?
Right: 5th rib
Left: 5th intercostal space
During inspiration the central tendon does what?
moves inferiorly and domes “flatten out”
What occurs during inspiration?
Diaphragm contracts and lowers.
- Right crus contracts => compresses walls of oesophagus => prevents gastric contents being suctioned up with decrease in intra-thoracic pressure.
- Caval opening widens.
Referred pain of diaphragm? Central region
Pain from the central region of the diaphragm will travel with visceral afferent fibres of the phrenic nerve and therefore be referred to skin of the supraclavicular C3,C4,C5 region.
Referred pain of diaphragm? Peripheral region
Pain from the periphery of the diaphragm will
travel visceral afferent fibres of
intercostal nerves and be referred to the skin
over the costal margins of anterolateral
abdominal wall.
Paralysis of diaphragm
• Crushing, sectioning or blocking phrenic nerve.
Hiccups (Synchronous Diaphragmatic Flutter)
Sudden contraction of diaphragm and closure of
glottis pulls air rapidly through larynx causing
“hic” sound.
• Reflex arc (vagal afferents; phrenic & intercostal
efferents)
Valsalva Manoeuvre
Increases intra-thoracic pressure which traps blood in great veins (impeding venous return) .when breath released Increased BF, increased HR, Increased BP => reflex bradycardia (decrease HR).
What is the blood supply to the superior surface of the diaphragm?
Musculophrenic artery and vein branch of internal thoracic from subclavian
What is the blood supply to the Inferior surface of the diaphragm?
Left and right Inferior phrenic vein and artery
Which aperture is the weakest (most susceptible to widening)?
Oesophageal hiatus as it is going through muscle not tendon
Fetal hiccups are important in strengthening and developing diaphragm, what happened without this?
Absence => pulmonary hypoplasia = death.
The oesophageal hiatus is located in what structure?
Right crus
The aortic hiatus is located in which structure?
Median arcuate ligament
Why can sectioning the phrenic nerve help with tuberculosis?
If tuberculosis is in lower lobe of lungs, sectioning phrenic with make it a little more comfortable as lower lobe is leaning on diaphragm
