Diaphragm Flashcards
Describe the embryological development of the diaphragm
It develops in the neck, mainly from the septum transversum. It picks up nerve supply from anterior rami of C3, C4 and C5. When the lungs expand during development, the diaphragm is forced inferiorly.
Name the origins of the diaphragm
1) Septum transversum
2) Pleuroperitoneal membranes,
3) Dorsal mesentery of the oesophagus
4) Ingrowth from the body wall.
Describe the origins of the muscular fibres of the diaphragm
Anteriorly from xiphoid process, then costal margin, ribs 11,12 and then posteriorly from the medial and lateral arcuate ligaments
What are the arcuate ligaments?
Thickenings in the thoracolumbar and psoas fascia
Describe the travel of the fibres of the left and right crus?
Left crus - passes vertically upwards and inserts onto central tendon.
Right crus - Pass vertically but some fibres cross over the midline of the left to form a loop around the oesophagus
Name the three openings in the diaphragm and what passes through them?
T8 - Right phrenic nerve and inferior vena cava.
T10 - Left gastric artery (up) and passing down is oesophagus, anterior and posterior vagal trunks and left gastric vein.
T12 - Thoracic duct, azygos and hemiazygos, and thoracic aorta
What is a hiatus hernia and what are the two types?
Condition where a small part of the stomach herniates through the diaphragm into the thorax. There are either sliding or rolling hernia.
Describe features of a sliding hernia
It is the most common, normally the intra-abdominal part of the gastro-oesophageal junction gets above the oesophageal hiatus. A section of the cardia is therefore above the diaphragm and allows stomach acid to secrete into the lower oesophagus.
Why is the pain of a sliding hiatus hernia worse after eating?
Compression of the oesophagus results due to the hernia presses against the wall of the feeding tube. Food can therefore get stuck in the oesophagus causing chest pain after eating. Also means the stomach acid produced irritates lower oesophagus.
What is a rolling hiatus hernia?
This is a less common hernia and occurs when part of the fundus of the stomach has herniated through the diaphragm but the gastro-oesophageal junction is still intact below the diaphragm.
How do rolling hernias present?
Dysphagia (swallowing difficulties)
What is a congenital diaphragmatic hernia?
This is a condition that occurs in new-born babies due to incomplete development of the diaphragm. A lot of the midgut structures pass into the thorax. Present with cyanosis and respiratory distress.
What occurs if there is blood or pus in the abdomen?
It can collect in the subphrenic space, especially if the patient is lying down. This can irritate the diaphragm and cause sensory stimulation.
