Diaphragm (dave's notes) Flashcards
Define the diaphragm
A thin sheet of muscle as a derivative of the inner layer, with its purpose being for respiration.
What anchors the diaphragm to the vertebrae? Which is largest?
The left and right crura. The right is larger than the left.
What are the attachments of the right crus? What path does this follow? Where is their innervation from?
L1-3. Fibres from the right loop around to the left of the oesophagus and sling this. Innervated from the left.
What are the attachments of the left crus?
L1-2
Where is the median arcuate ligament found?
Between and behind both curs.
From what does the median arcuate ligament arise?
The median arcuate ligament is a thickening of the psoas fascia
From what does the lateral arcuate ligament arise?
The lateral arcuate ligament is a thickening of th elumbar fascia (quadratus lumborum).
The median and lateral arcuate ligaments also give off muscle fibres. From where else do diaphragmatic muscles slips arise?
From the ribs, Tansversus abdominus, and the xiphisternum
Describe the central tendon of the diaphragm
The central tendon is shaped like a three leaf clover pointing forward, with lateral leaves towards the paravertebral gutters.
Where is the vena caval opening in the diaphragm?
Between the central and right leaves of the central tendon
List the diaphragmatic openings
Aorta, azygous and thoracic duct Oesophagus, vagal trunks, oesophageal branches of the left gastric vessels Hemiazygous vein Greater and lesser splanchnic nerves Sympathetic trunk Subcostal nerve and vessels Left phrenic nerve Neurovascular bundles of T7-11 Epigastric vessels Extraperitoneal lymph vessels
What passes through the aortic opening? At what level is this?
T12.
Aorta, azygous and thoracic duct
What passes throughout the oesophageal opening? At what level is this?
T10
Oesophagus, vagal trunks, oesophageal branches of the left gastric vessels
What passes through the vena caval opening? At what level is this?
T8
The vena cava, right phrenic nerve
Where does the hemiazygous vein cross the diaphragm?
It passes through the left crus
Where do the greater and lesser splanchnic nerves cross the diaphragm?
They pierce each crus
Where does the sympathetic trunk cross the diaphragm?
Behind the medial arcuate ligament
Where does the subcostal nerve and vessel cross the diaphragm?
Behind the lateral arcuate ligament
Where does the left phrenic nerve cross the diaphragm?
It pierce the dome
What passes between digitations of the diaphragm and transversus abdominus muscle?
The neruovascualr bundles of T7-11
How do the superior epigastric vessels cross the diaphragm?
I don’t know
What passes directly through the diaphragm????
Extraperitoneal lymph vessels pass directly ???
List two diaphragmatic congenital herniae and their locations
Bochdaleck (back)
Morgagni (front)
List two acquired diaphragmatic herniae
Sliding
Gliding
Define a sliding diaphragmatic hernia
This is the commonest type. Arises from the phreno-oesophageal ligament becoming stretched and the junction rising up into the thorax
Define a gliding diaphragmatic hernia
Para-oesophageal
What is the blood supply to the diaphragm?
The right and left inferior phrenic arteries. Intercostal and subcostal arteries also supply the margin.
What is the nerve supply to the diaphragm?
The phrenic nerve to each side. These fibres radiate out in three branches (M and S ???)
During quiet respiration, what is inspiration due to the work of? What muscles are accessory?
The diaphragm, intercostal muscles adjacent to the sternum and the scalene muscles. Sternocleidomastoid and the external intercostal muscles are accessory
How does expiration occur? What muscles assist?
Largely passive, but external oblique, internal oblique, and transversus abdominus can assist.
What are the layers of the inner layer of thoracic muscles?
Subcustal, innermost intercostals, and transversus thoracis.
